Boom Zoom - A Lifter Love Affair

[ForkliftCertified (Rob Weston)]

Hi all, I figured it was about time I finally sat down and wrote a proper build diary. For those of you that don’t know, this is Boom Zoom, my 4 wheel drive lifter beetleweight robot:

But it didn’t always look like this. Below I’ll be documenting the design, build and iteration process for this little guy, from my very first combat robot put together with a hacksaw, drill and very little clue to the current version, made using lots of 3D printing, CNC machining and lasercutting. I’ve learned a lot in my time developing this robot, and I hope some of that helps you in your own designs

[Jack (Jack Franklin)]

[ForkliftCertified (Rob Weston)]

It’s finally here! Sorry about the wait, been a busy few weeks.

Boom Zoom MK1

Back in late 2021, I was bored out of my mind. The pandemic was still in full swing, and in my desperation for something to do I stuck the reboot series of Robot Wars on. I quickly became hooked, and after consuming all Robot Wars content I could find, moving onto Battlebots and after exhausting all avenues there, I found the BBB Beetleweight event videos. Building one of these machines looked achievable even to someone like myself with no marketable engineering skills or background, and after doing some further research (Read: Watching Craig’s excellent breakdown of Snappy, and listening to Spinnerproof as they went from fans to builders) I felt ready to build my first robot! But what to build…

While watching Battlebots I’d slowly but surely fallen in love with Whiplash. The way it bullied opponents around, grappling and lifting them with ease really appealed to me. It seemed able to match even the scariest robots of its time without having the same level of offensive weaponry as a lot of them, instead relying on driving skill and tenacity. This was right after season 5 aired, and the version they ran without a spinner during the fights with Valkyrie was fresh in my mind. Scaling something like this down to 1.5kg seemed very doable, so I opened up Sketchup and after a few nights of effing and jeffing, had something vaguely resembling a robot! But what should I call it? As some of you may know, I grew up on a dairy farm, and I wanted to pay homage to this by incorporating it into my robot. I ended up going with the name Boom Zoom, which is a shorthand name for a telehandler. What’s a telehandler? Well they look like this. I hope the reason for the name is pretty obvious.

I set myself a few challenges when designing it: It had to be fast, durable, and invertible. I wanted something that would put on an entertaining fight, even if that meant taking a beating. To that end I went with a 650mah 4S LiPo battery, 4x BBB 22mm brushed gearmotors and mounts (one for each wheel), 2x BBB Brushed ESCs (V1), an FS2A receiver, BBB 3A BEC, and a generic 30KG/CM servo off Ebay for the weapon. The link was an XT60 mounted with the BBB link mount kit, with some 30A fuse wire in the link itself. I used M4 woodscrews for the majority of the construction, with M4 bolts holding the lid on using nutstrip. The wheels were 3 inch Fingertech foamies held on with aluminium twist hubs, and the titanium forks and aluminium servo mount were also from Fingertech. For the weapon, I used a brass cabinet hinge for the pivot point on the lifter, and for the weapon mechanism I used the same loose linkage as Snappy, with a piece of HDPE mounted to the servo horn pushing against the lifter without being rigidly attached to it, and some elastic as a return mechanism. This was simple to engineer and would protect the servo a lot better than a more rigid mounting system. I used a mix of black 5mm and green 10mm HDPE for the construction of the chassis.

To be blunt, it was a mess. I’d not put the slightest thought into how the robot would fasten together, and I hadn’t added a single fastener or hole for one anywhere on the model. The side rails were 5mm HDPE, and the entire thing was ginormous for a beetle. That being said, it was my first go at this whole robot thing, mistakes were gonna be made. Anyway, time to build it!

I started with a cardboard mockup of the chassis to get a feel for the dimensions, then marked out the dimensions of the panels on my HDPE stock with a sharpie, set square and ruler. I cut the pieces with a hacksaw, and cleaned them up using a file, sandpaper and a wood plane. As with most things cut with hand tools, nothing quite lined up, so plenty of extra fettling was needed to get it all to go together. For the holes I marked out the center points with a sharpie, then center punched them and drilled them with a cordless drill. For the motor holes I used a 22mm Forstner bit. With basic hand tools it was hard work, but the bulk of the chassis was cut and assembled in a couple of weeks!

Once the chassis was together, the electronics needed soldering up. I hadn’t soldered anything since secondary school, but the BBB wiring guide and a little help from some other builders online made it a cinch. I did end up cutting the wires much too long, but the chassis was big enough to make this not really a problem. I also put the motors on XT30 connectors, to make swapping them out easier in the event of them getting mulched.

For any robot to pass a tech check it needs a few things, so I fashioned some sharp edge protection out of whiskey corks, drilled a locking bar hole for the lifter into which slid a steel rod, and made a cradle out of an old Playstation 1 game, Sabrina the Teenage Witch: A Twitch In Time! This would be my cradle for around 2 years, and had the game in the case the entire time.

I ended up adding a few details I’d never bothered to CAD, such as some struts to mount the front armour and some extra armour/bracing panels on the lifter, then finished it off with some snazzy decals! I also took the time to loctite every screw, secure the connectors with cable ties and apply some liquid latex to the wheels. Overall, I was pretty happy with the result! In testing it was fast, invertible, could overturn another beetleweight, self-right, and push quite well.

With the robot all finished, there wasn’t anything left to do but enter it into a competition! I ended up choosing BBB’s 2022 Beetle Brawl, and was lucky enough to snag a spot. Flash forward to the day of the event, after a very nervy morning I made it through safety without any issues.

BBB Beetle Brawl 2022 - Full Competition - Bristol Bot Builders Beetleweight Combat Robots

Here’s the fight video for the event, if you want to see them my fights are at 16:27, 43:04 and 1:05:07.

I’ll spare you the nitty gritty of each fight and focus on my takeaways from them. In my first fight I found myself dominated by Enigma, with its much better ground game making frontal attacks a non-starter. Enigma was also extremely well driven, meanwhile between my big wheels and very sensitive steering I found it hard to stay squared up and I ended up oversteering quite a lot. I was happy to get some half-lifts in during the fight, plus a self-right and a wiggle free from a very precarious situation near the OOTA zone. Ultimately though my inexperience showed, and ended up down the pit thanks to Enigma forcing a driving error from me. Still, my robot was in one piece, and I had a redemption fight ahead of me!

In my second fight I was able to get under Disorder from the sides pretty well, and my beefier drive setup let me out-push, overturn and pin it pretty nicely. I was going for the OOTA but didn’t quite have the angle or the leverage to pull it off, so I settled for immobilizing it instead. Not a lot more to say about this one, I was buzzing to get my first win on the board and again not take any damage, anything else was a bonus at this point!

My third fight was quite an eye-opener. This is the first time I’d fought a spinner, and while there are plenty more powerful weapons out there than Gertrude’s it was more than enough to basically write off this version of Boom Zoom. For starters, it ripped off a piece of front armour which wasn’t great. 3 M4 wood screws clearly isn’t enough to withstand a horizontal spinner, and the threads were pulled out on all 3 mounting holes. My wheels were also chewed to hell, and 2 of my motors separated from their gearboxes from the force of the hits. The hits to the lifter also managed to snap the elastic, disabling the weapon return, and shear the screws holding some of the arm together. The hits to the side where the front was torn off managed to hit the exposed front edge of the 5mm frame rail, buckling it as well. Clearly the robot wasn’t cut out to fight spinners, especially horizontals like Gertrude. I was very happy however to be able to take the fight to a judge’s decision, it showed I’d built something at least sturdy enough to put on a good show, which is a moral victory if nothing else!

Much to my surprise, at the end of the day Boom Zoom ended up winning Best Newcomer! I was over the moon at this, and it’s safe to say I was absolutely hooked on fighting robots. I met a lot of lovely people that day who would go on to be great friends too. On the train home I was already writing a list of ways to improve the robot, but I’ll go into that when I write about Boom Zoom MK2, hopefully this next post won’t take as long!

[Strang_H (Henry Strang)]

You’re telling me this guy Booms and Zooms???

Great writeup bud. Really interesting to see how we both came to Beetles in the same way - Snappy breakdown and a bit too much Spinnerproof for any sane individual.

The space inside BZ V1 is insane, I reckon you could fit a decent antweight comp in there

[Kraken4me (Alex Revell)]

Didn’t Boom Zoom go to robot rebellion (or some event of a similar name)? I may have seen a video of it there.

[ForkliftCertified (Rob Weston)]

Yep! Boom Zoom has been to Robot Rebellion 2022, 2023 and 2024. If you saw it in a video that was probably the 2023 version, I’ll be getting to that one in a later post

[T_Y (Thomas Yau)]

It’s cool seeing the original Boom Zoom, I’m much more familiar with your more recent iterations

[hhills (Harry Hills)]

Hah, Craig’s video and spinnerproof to get me though night shifts (ironically occasionally operating a telehandler) brought me back to beetles. Love that’s a shared experience.

Just want to say as much as we all want to see content, please do take your time. Boom Zoom and its evolution (and the success that has come along with it) is a poster child for How To Do Robots Good with the deliberate ramp up in technology and skill version to version. I can see it as an excellent case study to wave at new builders.

[ForkliftCertified (Rob Weston)]

Howdy all, finally had a free weekend so getting this next part written up wasn’t too bad! Thanks for all the kind words so far, wild how many of us took such similar roads to get here Without further ado:

Boom Zoom MK2

So following on from Boom Zoom’s first event, I decided to shelve MK1. It had taken an absolute beating, and I had quite a few changes I wanted to make. Rather than retrofitting these onto an already knackered chassis, the easiest course of action would be to start fresh. My list of changes included:

1. Modular front attachments including forks and a wedge

2. Better ground game

3. Sturdier front armour

4. Make the whole robot easier to work on

5. Thicker frame rails

I also went about designing and building this version in a completely different way to the last one. I hated using Sketchup, and it ran terribly on my machine. On the advice of a few other builders I made the jump to Fusion 360 as my CAD software of choice. Like Sketchup it was free, but it seemed a lot more powerful and was much more widely used by roboteers. I was recommended the excellent series of tutorial videos by David Small, where he shows how Fusion’s tool suite can be applied to combat robot designs.

How to Use Fusion 360 to Design a Combat Robot (Foxic CAD-A-Long: Part 1)

By following this tutorial, then adapting these techniques to my own design, I was able to CAD the new version of Boom Zoom in a little under a week! I found working with Fusion difficult to get my head around at first, with the sketch and extrude method of design being a big departure from how Sketchup generates shapes. That being said, by the end of this design I was a lot more comfortable with the program, and for anyone looking to get into CAD I’d highly recommend skipping Sketchup and jumping right into Fusion with David’s tutorial. Anyway, here’s what I ended up with:

First things first, I opted to change the colour scheme to match the farming theme of the robot! My family have always gone with John Deere machines, from tractors to lawnmowers and everything in between, and no other robots were rocking this combination of colors at the time. This would go on to become my default colour scheme for all future robots. It’s nice to have a brand I guess.

Getting back to the design itself, this was already a big improvement over my first stab at CAD, as I actually had holes for fasteners this time around! In terms of design changes, I upped the side rails to 8mm HDPE, and dropped the back down to 8mm to match. I also added a full 8mm mount plate behind the front armour, the intent being that the hole pattern on this plate would support multiple front armour packages. For the default front armour I chose 2mm Grade 5 titanium, as this offered great strength for its weight and can be worked with basic power tools. For the wedge configuration I went with a 25mm piece of HDPE cut diagonally to form the angle of the wedge. For making this version I invested in a couple of power tools to make the process easier, namely an angle grinder and circular saw for cutting the titanium and HDPE respectively.

To make life a little easier, I printed 2D profiles of each panel I was cutting onto a sheet of A4, then cut these out, stuck them to the HDPE and used them as templates to cut/drill around. Between this and using the circular saw, this chassis came together much more quickly. Only once it was all together did I realize I had an issue - I’d messed up one of the motor holes, and now only 3 wheels were on the ground at any one time. This was because I’d drilled the holes with a hand drill, and one hole was at a slight angle. To fix this going forward I invested in another tool, a drill press to ensure straight holes, and recut this panel. Using the drill press to make the holes worked a lot better, and soon I had a fully together chassis with all 4 wheels on the ground.

The next step was to cut the titanium! I used the same method of printing 2D profiles straight from the CAD model and gluing them to the ti, then cutting them out using my angle grinder with a cutoff disc. I then used a flap disc to clean up the pieces, and a center punch and tungsten carbide drill bits to bore out the mounting holes.I mounted these to the chassis with M4 bolts and nylock nuts, with a few rubber washers between the armour and chassis to provide some shock absorption.

For the forks, I sent a dxf of the 2d profile I wanted cutting over to Sion, who was kind enough to hook me up as part of a group order with KCut. The forks were waterjet cut out of 4mm Hardox, and with a little dremelling ended up fitting very nicely. The mounts are designed to be easy to make, disposable and ablative, as well as having downward travel limits built in to prevent the forks folding under the robot and immobilizing it.

I then cut the wedge, once again with the circular saw. I wasn’t entirely happy with how these came out though, as the wedge was way off the ground and I thought it’d leave the robot vulnerable to undercutters or horizontals with ground game of their own. I got around this by designing an alternate wedge config out of 6mm HDPE, with a hinged element that rested on the floor.

At this point, the chassis was about done but looking a little drab. I took it apart and began spray-painting, first doing a coat of gray primer, then green and yellow over the relevant parts. I gave the twist hubs for the wheels a coat of yellow as well for good measure. Overall I was pretty happy with the effect, but found the paint flaked off the HDPE very easily, even during gentle handling of the robot. I finished the cosmetics by adding a big John Deere logo vinyl sticker and the name of the robot along the lifting arm, both cut by my partner.

For the electronics, I cut out the core of my previous wiring and replaced it with a BBB breakout cable, with every single part of the robot on some kind of connector to make swapping them out easier. I also swapped out the battery for a smaller 4S 450mah pack, saving a few grams over the old one.

With all this done and the robot together, it was time to snap a few beauty shots:

I already had an event in mind for Boom Zoom MK2: Rapture Gaming Festival. This is seen as one of the biggest events of the beetleweight calendar, and usually attracts a very high standard of robot. Given the fact my last robot had been written off by the very first spinner it faced I was a bag of nerves going into this one.

Rapture Gaming Festival 2022 Robot Rebellion - All Fights - Beetleweight Robot Combat

Anyway, here’s how it went. My fights are at 1:18, 23:57, 50:49, 1:55:29, 2:38:03, and 2:55:15. The new forks worked well against Brug, This Is Not A Drill and Rust In Pieces, allowing me to manoeuvre them around and overturn them successfully. My fight with TINAD in particular was a fantastic driving match and a tense JD, with my drive starting to lock up towards the end of the fight. I later found out this was due to the twist hub working its way down the motor shaft, causing the wheel to rub against the chassis. This was easily fixed by moving the hub back down the shaft and re-tightening the set screw. My fight against Let The Good Times Stroll worried me, it had an insanely powerful weapon that could knock out a robot in one hit if it got a good connection. I got very lucky in Stroll not being able to move forward properly, allowing me to pin it against the wall and overturn it, bending the weapon assembly and causing a massive ESC fire which won me the fight! I was surprised my 30KG servo could handle overturning a 2KG robot like Stroll, and elated to have won my heat without taking any damage!

My round of 16 fight was against Night Fury, and here is where I encountered the first problem with my modular fronts: they took FOREVER to swap. Removing and redoing 6 nylock bolts per side took an absolute age on my own, thankfully Andy offered a hand with his electric screwdriver which sped up the process immensely and meant I was ready in time for my fight. Fat lot of good it did me! Night Fury’s sharp, thin blade cut through my HDPE wedge like butter, got around to my side and took out an entire drive side, exploding the motors with direct hits to the wheel hubs. Getting beached on my own shredded wheel and counted out was a mercy really, and once again a horizontal spinner had completely outclassed Boom Zoom.

This time though the bot was not written off! I was able to swap out the ruined wedge, wheels and motors and get the robot back together in time for a 10 robot rumble to close out the day. This was a weird one, for starters the lifter elastic came undone almost immediately, then a short way into the fight my robot seemed to kind of die when gently pushed into a corner. It’d continue to twitch and briefly respond to input at points, but it was effectively immobilised. The robot worked fine after unplugging the link and plugging it back in, and I’ve never had this issue again with any of my robots. Things went from bad to worse when BFM landed on top of Boom Zoom, snapping the lifter arm in 2 places and knocking the servo loose from its mounting bracket. This damage was catastrophic for this version of the robot, and would require an entirely new lifting arm as well as replacing several other damaged components from the rumble.

For this reason I decided to once again go back to the drawing board and redesign the robot, but this time I’d been chatting with loads of builders at the event, getting pictures of the insides of their bots and making notes of ideas I’d like to try in my own build. I was very happy with how MK2 had performed, all the changes I’d made since MK1 had played a part in making it a better robot (except maybe the wedge) but I had a clear vision of the direction I wanted to go with the robot and felt ready to take the next step in its development. Tune in next time for what I consider the single biggest step up in this robot’s development cycle: Boom Zoom MK3!

[ForkliftCertified (Rob Weston)]

Hey All! The build log for these next versions will be considerably longer as each version competed in several events, with numerous smaller changes taking place between these.

Boom Zoom MK3

Once again a new version of Boom Zoom had basically been written off after its first event, which was getting pretty tiring. I really wanted to take whatever came next to a level where it could survive multiple events without needing a rebuild. I’d been chatting with loads of builders at Robot Rebellion 2022, and decided to steal a load of the best ideas they’d had (and add a few of my own) for Boom Zoom MK3. The biggest changes were:

1. A much smaller, CNC machined chassis.

2. 3D printed TPU front armour and wheelguards.

3. Ditch the foamies for cast polyurethane wheels.

I went with a CNC’d chassis to ensure it would go together first time, with none of the errors that come with a hand cut chassis. It also makes fabricating spares much easier, and makes the whole build process much less labor-intensive. This was also the reason I wanted to try 3D printed armour, as well as being able to iterate on these much more easily than any other manufacturing method.

Only one problem: I didn’t know how to actually make any of this! Still, first things first, time to design the thing. I jumped back into Fusion 360 and before long had something I was pretty happy with.

As you can see, this new version was absolutely tidgey compared to the old one, making it pretty normal sized by average beetle standards. The Ti front panels are gone and the new TPU fronts are secured via a single M5 nut and bolt through 2x10mm bulkheads, which makes swapping out front armour packages incredibly easy. TPU has also been used for the top panel in the lifter, with a 4mm RAEX 400 steel panel on the front to eat the hits from those mean spinners. This version is also much more forky, featuring a grand total of 6 (count em, 6!) forks also made from 4mm RAEX 400. I decided against painting this version (except the RAEX bits) and instead of HDPE went with RG1000 for the green plastic and PE500 for the yellow plastic.

Not having a CNC router of my own at this point, the chassis was cut by the lovely Mr. Strang and even came with sweeties!

A few last bits were hand-cut by myself such as an 8mm back panel and a couple of spacers between the front bulkheads, but even with these it went together like a dream! I was really happy with how this came together, it looked so much cleaner than my hand builds but still had some of that element of high-functioning jank they’d so proudly displayed.

For the TPU I did decide to take the plunge and buy a 3D printer of my own. I went with a Sovol SV01 Pro, which is effectively an Ender 3 with some upgrades like a bigger bed, auto leveling system direct drive extruder. After some dialing in and messing with the slicer settings, it was pooping out pieces without a care in the world!. Alongside the other bits you can see on the robot I also got some wedge designs printed, though these never saw combat.

For the wheels I basically followed Just Cuz Robotics’ excellent guide on cast wheels:

How to Make Custom Wheels for Your Robot - Molding/Casting Polyurethane

I designed a 3D printed core with lots of keying features for the cast polyurethane to wrap around and grip, along with a mould for the wheel core to sit in during casting. I then printed a set of prototypes out of PLA-ST, greased up the moulds with vaseline and cast the wheels using Vytaflex 40 Polyurethane and a small amount (1% of the total mixture) of black dye. I mounted these wheels on Pololu universal mounting hubs.

I found demoulding the wheels to be a total pain and ended up having to cut the wheels out of their moulds with a hacksaw, so I decided on swapping to TPU moulds and wheel cores for future attempts.

For the lifter retraction I wanted something a little more stable than a length of elastic, so I popped into Claire’s and picked up a pack of hairbands. I secured these with zip ties, reasoning that a closed loop of material would be less likely to pull through its mounting hole or snap like the old elastic was prone to.

Very little in the electronics was changed from MK2, the only change of note being swapping from an XT60 to an XT30 for the link. I also added magnets to the base of the robot to improve traction, along with the new grippy wheels I was hoping this would absolutely bully other robots around on a steel floor.

I finished off by adding the customary John Deere decal and printing some optional top armour, and just like that, the robot was done! I took it for a spin at Robonerd Pinball 2022 with some 3D printed standins while I waited for the metal order to arrive and was very happy with how it did, even if I did drive it into the pit!

RoboNerd Pinball - Boom Zoom

After Robonerd I replaced the wheelguards with some bulkier ones with bumpers to prevent getting stuck on its side, and fitted the metal parts once they arrived. With that it was time for Boom Zoom MK3 to see combat, which it would first do at BBB Champs 2022!

BBB CHAMPS 2022

BBB Beetle Champs 2022 - Full Competition - Bristol Bot Builders Beetleweight Combat Robots

BBB Beetle Champs 2022 - Whiteboard Fights & Awards - Bristol Bot Builders Beetleweight Robots

My fights are at 0:00 and 36:50 in the first video, and 6:55 in the second video.

For my first fight I was drawn against Toxin and Keith the Teeth. Not knowing what Keith was but scared it was some kind of crusher, I slapped my top armour on as a precaution. The fight itself went about as well as it possibly could have, with Boom Zoom knocking out both opponents within a minute.The TPU armour stood up well to the hit it took from Toxin, and the robot was good to go again with basically no repairs! Next up was End Boss, which was pretty much the worst draw possible for me. End Boss spent most of the match outreaching Boom Zoom’s forks and bouncing it off the roof, with a particularly nasty shot bending the baseplate and knocking the servo free from its mounting brackets. The weapon still partially worked even with the servo dislodged, well enough to act as a self-righter anyway. I did at points take the fight to End Boss and managed a pin and lift onto my own lid, but thanks to the dislodged servo I couldn’t convert this lift to a grab, End Boss wiggled free and I ended up pitting myself. Crud.

The damage from this fight was pretty gnarly, aside from the baseplate and servo damage the front armour was looking majorly worse for wear, and half a wheelguard had been completely ripped off. The forks were also varying degrees of bent and chipped, but honestly this was all fixable! I replaced the front armour and forks with spares, bent the servo bracket and baseplate back into shape with some pliers and reseated the servo, and just like that I was ready for a whiteboard!

Some very scary spinners in this one, but once again Boom Zoom held up well against them, getting some more good lifts and what was probably my proudest moment of the day, pushing 3.5 kilos of robot from one side of the arena to the other! Winning this one was a nice way to end the day. I felt had the draw been a little kinder I could’ve gone further in the main competition, but was still happy with the robot’s overall performance, and happier still it had actually survived without too much damage! The cherry on the cake was the “Most Improved” award that Boom Zoom walked away with, I’d really gone for it with this version of the robot and it meant the world to see that recognised.

Overall the changes held up great! The printed armour and mounting was a big success, both in terms of maintainability and durability. The new forks did their job, the lifting arm and elastic took several shots from verts without failing, and the tyres and magnets gave it a heck of a lot of push. For once I wasn’t staring down the barrel of a total rebuild after the event, which was a huge relief, but I still had some changes I wanted to make.

First up, I wanted a setup to fight drums and egg beaters with. In that last whiteboard, Bakugo had bent up a couple of forks pretty badly, so I wanted something a little more suited to fighting that kind of wide weapon. I went with this wide “claw” design, the idea being that the radius of the fork’s curve was bigger than that of a standard Fingertech Beater Bar, so all a weapon that size could do is grind against this surface without biting properly. Sadly I didn’t have time to get these cut out of metal, so some hastily printed TPU substitutes would have to suffice. I also thickened up the wheelguards so they wouldn’t be torn off as easily.

Battle In The ‘Burgh 2

Before I knew it, it was time to fight again! This time I made the long trek up to Scotland to compete in Battle in the ‘Burgh 2. This was my first time taking largely the same robot to its second event, and boy was it nice not having to rebuild this thing in the month between BBB and Burgh. It was also a good opportunity to learn a bit more about this design, 3 fights, none of which went 2 minutes isn’t a good sample size and this being a 2-day event had the promise of a lot of arena time.

BITB2 - Fight Night Round 1

BITB2 - Fight Night Round 2

BITB2 - Fight Night Round 3

BITB2 - Top 16

My first 4 fights are timestamped, skip to 27:50 of the third video for my play-in rumble.

BITB2 - Saw Loser Bounty

My Bounty Hunter fights are at 0:00, 1:53 and 4:20.

In my first fight against Uplift, a couple of fatal flaws in the robot were revealed. First off, the new anti-drum attachments were ripped apart. I’d put these on as the claw shape would allow me to control the high front end of Uplift’s chassis easier, but instead they were just shredded by the spinner. To make matters worse, I found that if Boom Zoom was knocked upside down with the lifter open it would become stuck in that position. The hairband didn’t have enough strength to retract the lifter from this position, and I was quickly counted out. Nuts.

I swapped out the mangled front for the default forks when I fought Panthor, and was very happy with how I performed. The magnets seemed to really like the floor in Shane’s arena, and the robot moved like it was on rails. I was able to bully Panthor around for the most part, but it did land a couple of solid shots before its weapon gave up the ghost. Despite this I was able to stack the robot awkwardly and narrowly get it counted out.

For 7th Circle it was much of the same, however I found myself losing the ground game more often than not once again, and getting popped into the air for my troubles. Once again that retraction problem reared its head, and I was left stuck upside down and counted out. The damage from this one was pretty tasty, another drive motor had come away from the gearbox, 7th Circle exploded a couple of my magnets which created some pretty sparks, and completely “fishhooked” a fork, bending it beyond the point of recognition. The repair job was majorly rushed for this, as Boom Zoom still had a shot at the top 16 by entering a rumble!

After scraping through the rumble without too many issues I once again was drawn against Uplift in the round of 16. I was a lot more cautious in this fight, attempting to go around Uplift’s side and bait it into making a mistake. This backfired when I left Boom Zoom’s backside exposed for a second too long. Uplift managed to catch my exposed link, breaking the wire and removing it from the robot.

All was not lost though! I could still enter the Bounty Hunter tournament for a shot at fighting Saw Loser. With basically no repairs to do except dig the spare link out of my toolbox I jumped right in, and after frauding my way through 2 fights made it to the final against Speeny. Ironically all of my anti-drum forks had already been mangled at this point, and my longer forks were also all trashed. I had no choice but to use my short forks, which Speeny got under every time. Eventually Speeny got me upside down, grinded against my lid for a while, then once again pulled out my exposed link.

4 cheap losses from 2 very obvious problems there, that was painful. There was a lot I wanted to do to the robot before I was happy competing with it again, which I’ll be diving into when I write up the next iteration of this robot: Boom Zoom MK3.5! See you then

[James_Draper]

Really great watching the gradual progression! You did well taking so many pictures.
I love how you have retained the look and feel of the robot despite completely redesigning almost anything.

[James_Draper]

looking forward to the next installment

[ForkliftCertified (Rob Weston)]

Back at you again with that Boomy content, hot and fresh

Boom Zoom MK 3.5

With 2 events under the belt of Boom Zoom MK3, I was feeling a little down on the robot. I felt the robot was 90% of the way towards being pretty good, but that 10% was really starting to show, especially at Burgh. At least I had some clear areas to focus on when looking at improving it! These were:

1. Find a way to self-right when upside down with the lifter open
2. Find a way to stop getting link sniped
3. Rework the fork setup to be more durable and able to get under opponents better
4. Find a way to stop the 22mm motors from separating from their gearboxes
5. Make the weapon more powerful

The solution to my first problem turned out to be pretty simple, all I needed to do was add some more hairbands into the retraction mechanism and hey presto, it can self right! I wish I’d tried this at the event, but hindsight is 20/20. It’s worth noting that the longer the forks Boom Zoom runs, the more hairbands are needed to self-right it. I found 3 hairbands twisted around a couple of times to add tension was more than enough for MK3.5 anyway.

For the second issue, a little more work was needed. All previous versions of Boom Zoom had the link hanging out the back of the robot, but it was clear after having it sniped twice in a day this was way too exposed. I instead mounted it to one of the side bulkheads, and cut a hole in the lid to access it. I replaced the link mount itself with a new XT30, which I drilled an M2 hole between the 2 terminals on and mounted with an M2 bolt. This is by far the most compact and lightweight mounting method I’ve found for links, and has been absolutely bombproof since I started using it. I 3D printed a small door for the link from PLA+ and mounted it with another M2 bolt. I mounted the XT30 at a height where it would slightly poke out of the lid, so that the lid itself would press down into the link and prevent it from going anywhere. Props to Sam Price for walking me through his own link setup on Sweg and Shrekt, it heavily inspired what I ended up doing on my own robot <3

For the third issue, it was back to Fusion to get some new forks designed. The old ones were bending up far too easily on vertical hits, so I dropped from a 4mm to 3mm thickness and added a lot more material in the vertical plane to prevent this happening. I also made them a lot longer to give me the reach advantage, and added a small barb to the lifter forks to help me catch opponents and lift them more easily. Another KCut order later and they had arrived and were ready to mount, but this time they were name-brand Hardox 400 instead of generic wear plate or RAEX. I also modified the front TPU armour packages, and printed them out of a darker TPU (Overture 95A for those wondering) which didn’t quite print as nicely but was much closer to matching the colour of the RG1000 the rest of the chassis was made out of.

For the fourth issue, Sam Price once again came in clutch. He advised using hot glue-lined heat shrink to encase the motor, giving it more support to hopefully prevent the motor backing off the gearbox. I’d been loctiting the screws to prevent this since my first build, but had still lost 5 motors in my first year competing to this flaw. I bored out the mounting holes for the motors to around 24mm and applied the heat shrink, then shrank it into place with a heat gun. I was pretty happy with the result, and it had the added bonus of the hot glue at the end of the motor working to support the wire tabs, which can often break off on these motors if not handled carefully.

For the fifth issue, I wanted something more powerful than the basic 30KG servo I’d been running in Boom Zoom up until this point. I came across these very swish DMOND DBS65168V servos, capable of 65KG of torque when run directly off 4S. My servo up until this point had been running directly off the receiver so was stepped down to 5V by the BEC, so I was very excited to be able to get a full 16 volts into the weapon and get it lifting much faster and with more power than before. Sadly these servos are no longer produced, but they’ve been absolutely bombproof in my setup as of the time of writing. Your own mileage may vary, as the servo in my robot is very protected by the indirect lifter linkage compared to a lot of other applications people use servos for. It was only about 20g heavier than the old servo, and fit the exact same mounting bracket and servo horn, yippee!

I also decided to stop running magnets on Boom Zoom. It was driving very differently in the arena to how it was on my kitchen floor at home, and I didn’t have room for a giant steel sheet to practice on in my flat. Between that, the extra work they were to replace if broken, and the weight they took up, I decided a move away from them would be for the best.

With all these changes in place I was certain I had finally created an unbeatable robot (not really) and all I needed was somewhere to run it! It was at this point I went to my first RoboDojo event. RoboDojo is much closer to me than pretty much any other event (less than an hour’s drive!) and you’re guaranteed at least 4 fights per robot you bring. You’re also able to bring up to 3 antweights and 3 beetleweights per event, making it hands down the best value of any event I’ve ever done. They also run an ant/beetle event every 2 months, making it a great place to really quickly dial in any new robots or improve on existing designs. I brought 3 of my ants and Boom Zoom along to the February 2023 event, hoping the upgrades worked as expected!

RoboDojo February 2023

Boom Zoom vs ???

Boom Zoom vs ???

Boom Zoom vs ???

Boom Zoom vs ???

My first and last fights were against Colin’s big wheeled pushers, Screaming Banshee and Little Grey Fergie. I was able to get under, push and lift these very well, but Colin’s big wheels allowed his robots to free themselves from nearly every situation. I did eventually manage to pit Screaming Banshee, but Little Grey Fergie took the fight to the judges who awarded me the win!

My other fights were against the compact black vert Disaster Area, who nibbled on my forks for a while and scored some decent hits before I was able to overturn and pit him, and Nightcall, who landed some monster hits to my front before I lifted his spinner directly into my lifter, nearly cutting all the way through to my internals. The lid was still usable after this, but the front armour was absolutely mulched by the giant vert of Nightcall. It had done its job of protecting the rest of the robot though, and I quickly switched it out for a spare set between fights.

This left me on 4 wins out of 4, but Judge’s Decisions are only worth 3 points instead of 4, so I had to settle for 4th place out of 26 behind the 3 robots who’d each scored 4 knockouts. I was still over the moon to reach my first top 4 finish, and every change I’d made between Burgh and this event seemed to make the robot better! The lifter had a lot more yeet to it, the motors survived some giant impacts, the link wasn’t sniped, and I got under all my opponents! The importance of practicing driving the same robot also can’t be ignored. If you scroll up a bit and watch my pinball run, then my Dojo fights, you’ll see how much more used to driving this robot I am, which can only help!

After this event there wasn’t a huge amount I wanted to change. I finally had a chance to get a proper wedge and anti-drum setup done, and here’s what I ended up with:

I dubbed this my “Jungle Man’’ setup after its resemblance to the ant of the same name. This 2-piece TPU wedge setup doesn’t actually scrape the ground but sits with 1-2mm clearance to prevent it getting caught on any floor seams. I used eSun green 95A TPU for this, as it seemed to print stronger than the Overture filament I had which is paramount for a horizontal wedge.

For this I went back to the drawing board on my original attempt at anti-drum forks, but kept the same principle of making the radius of the fork bigger than that of the typical drum/beater they were designed to face. I got rid of the upper hook as I felt it would be easy for drums to catch that rather than grinding against the front face of the fork. I once again got these from KCut, but this time they were 8mm Hardox 500, making them even harder than my regular forks. For both this and the wedge setup I opted to replace the lifter forks with a small TPU shovel to protect the lifter from hard impacts.

I also don’t think I’ve ever shown a picture of the internals all wired up and in place, so here’s what that looks like:

With that it was time for another Dojo, here’s how it went:

RoboDojo April 2023

Robodojo Beetleweight Round 6

Fights are at 12:56, 20:28, 29:58, 36:34 and 44:32

My draw this time was a lot tougher than my last Dojo outing: Kreigmesser, Zephyrus, Gaelic Gladiator and Nightcall once again. I did still manage 4 out of 4 wins, this time all by knockout! The drum forks worked great against the Fingertech Beater Bar of Gaelic Gladiator, and the rest of the changes held up well against all my opponents really. The forks were taking damage but were always easy to bend back into shape or file back into sharp points. I got stuck under the free-standing wall in the 1st place playoff to come 3rd overall, which was still my highest ever placing at a beetle event at the time

With Robot Rebellion 2023 on the horizon, there weren’t a huge amount of changes I wanted to make to the robot. All I really did was cook up some new top armour, and some low-profile front armour packages for fighting top attack robots and non-spinners respectively. The idea with the low profile fronts is to keep the wheels exposed and leave as few catch points for the opponent to pin me as possible.

A fresh coat of paint later and we were ready to go again. Thanks to winning its heat last year, Boom Zoom got an automatic invite back as the #12 seed!

Robot Rebellion 2023

Boom Zoom - All Fights From Robot Rebellion 2023

For this event we actually knew our heat opponents ahead of time: Dolos, Data Breach and Digestive, the 3 Ds. With this in mind I was pretty happy to have cooked up a hammersaw and control bot setup ahead of time as this covered 2 of my 3 opponents in this heat.

Against Dolos, the hammersaw setup held up well. Dolos was unable to get through the top armour, and I was able to wiggle free of most of the pins he landed, but he landed a solid shot on the underside of the lifting arm, snapping one of the struts at the elbow. One of my wheels did eventually come off on its own, the set screw had managed to work loose over time and was too rounded out for me to tighten. Going down to 3 wheels barely affected the robot’s mobility however and I was able to eke out a judge’s decision for the win! I swapped out the arm for a spare I had, and replaced the rounded out wheel hub ahead of my next fight. The control bot setup also worked well against Data Breach, he had no catch points to pin me with and eventually got stuck in the arena wall and counted out. With Digestive it was basically the same strat as every other vert I’ve fought, stick the forked spinner armour on and flip it over till it stops moving, which worked a treat!

With that I’d won the heat and moved on to fight Wheely Big Lad, a Starchild-inspired kinetic thwacker. I set up by adding the top armour and low profile fronts, without any forks except the lifter forks. My strategy was to keep to the side of the lad, keep my lifter raised in the air and spear the forks through the wheel spokes. This worked well until the lad got a solid hit on the wheelguard, exploding it and wrapping it around its weapon. At this point an unstick was called and the wheelguard remains were removed from the weapon of the lad. The fight resumed, and in my haste to get the fight over and done with I pushed the lad over the pit, but its big wheels saved it and I ended up in the pit first. Oops.

Now I was out of the competition it was time to whiteboard! I replaced the exploded wheelguard and was ready to go again, and in I went with Bby Shrekt. Again it was time for the standard vert setup, but Shrekt is no standard vert. It’s one of the best of an already very effective type of robot, and is rightly feared across the scene. My approach was to avoid the forks and try to attack the parts of Shrekt’s front that aren’t protected by forks or its own weapon. I had mixed results pulling this off, Shrekt managed to catch a fork early on and completely pull both the fork and the bottom part of the lifter strut off, but I bounced back and landed a good pin in return. Eventually Shrekt’s weapon died of its own accord, but I couldn’t capitalize with a lift due to the half-eaten lifter. The rest of the fight was a pretty even pushing match, but the judges ended up giving me the win!

In the aftermath of this event I decided it was time to retire this chassis of Boom Zoom. Both of the lifters had been broken, the chassis as a whole was looking pretty sad, and I was ready to try CNCing my own with a few tweaks. I was really happy with how MK3 had done, and in my opinion this version of the robot is what took it from “just here for a good time” to “I could actually win something with this” which is something I aspired to but never really expected from this robot. This would mark the end of MK3’s service life, join me next time for another wall of text about MK4!

[ForkliftCertified (Rob Weston)]

Boom Zoom MK 4 Build Diary

Boom Zoom MK3.5 had come and gone, and at this stage I was at a crossroads of whether to go for another total redesign, or create a more refined version of basically the same robot. Not satisfied I’d learned all I could from MK3.5 I chose the latter, and began work tweaking the existing design to address some of the small flaws I’d noticed. These were:

1. With them being rigidly mounted, only 1 lifter fork would be on the ground at any one time.

2. The rear wheels didn’t entirely clear the baseplate, meaning if an opponent wedged under they could take all of the robot’s wheels off the ground.

3. During awkward lifts the robot would tip forward, taking the wheels off the ground.

4. The wheelguards had very weak layer adhesion and impact resistance thanks to using an unsuitable filament.

5. The M3 set screws in the wheel hubs were rounding out and getting stuck/falling off the shafts with use.

With this all in mind I jumped into CAD and began work! I won’t bother with pictures here as it’s visually nearly identical to MK3.5, instead I’ll jump right into how I tackled each problem:

The first issue was pretty simple to fix, the forks were secured to the lifter via 2 bolts. By removing the top bolt the fork would pivot on the bottom bolt, but was still limited in how far it could rotate by the fork’s geometry. On the CAD I just removed the top bolt hole entirely so it wasn’t reducing the overall strength of the lifter. Now both forks could rotate a little and keep in constant contact with the floor! If only all the fixes were that easy…

Fixing the second issue involved moving the wheels back a little. 3mm backwards was enough to fully clear the baseplate, but this then made the drive motors clip into the back panel. I got around this by designing some pockets into the back panel for the motor to sit in. That wasn’t so bad either!

The third issue was solved by limiting the upward travel of the non-lifter forks, tweaking the design of the front armour to stop them rotating upward past a certain point. This allowed them to act as outriggers, giving me much more leverage when lifting and stopping the robot falling onto its face. In some test lifts the front wheels stayed on the ground the entire time YIPPEE!

The fourth issue was solved by swapping yellow filaments from E-DA 97A to Polymaker 95A, which is a fair bit softer and much more impact-resistant. My hope was that this new material would flex much more, hold together better and NOT wrap itself around any more spinners!!!

The fifth issue was still straightforward to fix but involved my least favourite job in all of combat robots: tapping. Following Jack Franklin’s advice, I drilled out the Pololu hubs from M3 to M4, then tapped the new hole and added an M4 set screw. These are much less likely to round out, get stuck or fall off and were a nice if time-consuming quality of life upgrade. Here’s a before and after example of this process:

This was also my first opportunity to CNC my own frame for Boom Zoom after picking up a used 3018 desktop router from Andy Davies. After watching some tutorials and generating some gcode using Fusion 360’s CAM suite I set the machine going and was left with a lovely pile of vaguely beetle-shaped plastic. I was able to add a little pocketing on the back panel to save some weight and make room for the motors, which went swimmingly. I 3D printed some jigs for drilling the fastener holes to make sure even the manual parts of the manufacturing process were idiot-proof.

For the fasteners themselves I swapped all stainless steel fasteners to 10.9 ones for better tensile strength, and went with torx heads on fasteners wherever possible, as these are less likely to round out than hex heads and easier to remove when bent.

Robonerd Football 2023

With all this said and done, the robot was ready to go! Once again the first outing for a new chassis would be Robonerd, this time for the football! My printer quickly squirted out a custom setup for mine and Sion’s team, Crystal Meth Palace FC!

FULL Beetleweight Football Unedited footage | RoboNerd 2023

Our matches are at 6:00 and 1:59:08.

The robot put in a performance not unlike that of Prime Vinnie Jones, and together we finished 2nd overall, denied joint first by a dodgy VAR call. Game’s gone.

RoboDojo October 2023

With the testing complete, Boom Zoom was ready for a foray into full combat, just in time for October’s Robodojo meet.

Robodojo Beetleweight Fights 14th October 2023

My fights are at 2:40, 5:32, 14:48 and 24:38.

Not a huge amount to say about this one, 4 knockouts all by getting my opponents stuck in various compromising positions was pretty sweet! The changes worked perfectly, and helped by some favorable draws and no other robot scoring 4 knockouts, Boom Zoom fought its way to its first event win! I asked around and to my knowledge this was the first time a non-spinner had won a beetle event since the pandemic! I was really chuffed, even more so at the robot taking no damage.

That being said, this event really wasn’t a good test of the changes made since MK3.5. Most of the robots I fought were either very favorable matchups, having issues of their own that made it an easier fight, or some mix of the two. I was anxious to get the robot back into the arena and see if this was just a fluke, or if this robot really was a contender now. Cut to 6 weeks later…

Battle In The ‘Burgh 3

It was once again time to make the trip up to Edinburgh, this time with basically no changes made between events which was a nice change of pace.

BITB3 - Fight Night Round 1

Apologies for the choppy video, the later fights are better. Vortex was an awkward opponent, the wide gap between its forks fit my front end perfectly, and I found it was able to win frontal exchanges every time. To make matters worse, Boom Zoom was catching the floor seams much worse than usual, particularly around the pit panel. This made driving around to the sides and capitalizing on Vortex’s gyro when turning pretty difficult, but I eventually managed the push down the pit I’d been looking for. The robot had been knocked around a fair bit but it was all cosmetic damage, and before long I was ready for fight 2!

BITB3 - Fight Night Round 2

This was a rematch from earlier in the year, and since then Mark had fitted a link door to Kriegsmesser, meaning I probably wouldn’t be winning this one the same way as last time. Frontal engagements were kind of a stalemate in this fight, but I took advantage of the vert’s gyro, got to the side, flipped it onto its weapon and got it to roof itself. The shock from this knocked the weapon motor and caused it to burn itself out against its own guard. I mistook this for a more serious fire and put down my transmitter, but quickly picked it back up when it became clear the fight was continuing! With Kriegmesser’s weapon down there wasn’t a huge amount he could do except push me, so I took my foot off the gas a bit and settled for a pushing match for the rest of the fight, which despite some near misses with the pit ended in a JD Boom Zoom win!

My third qualifying fight sadly didn’t happen, as Downward Spiral was left irreparable after an earlier fight, which meant with a 3:0 record I automatically qualified for the top 16!

BITB3 - Top16

My top 16 fights are at 8:50, 15:11, 20:00 and 23:50.

Another rematch, this time from ‘Burgh the previous year in 7th Circle. I felt a lot better about my chances this time around having fought lots of very similar robots in the year since our last fight. This started well, with Boom Zoom getting under 7th Circle most of the time, but a good counter from 7th got Boom Zoom upside down. By following up with another hit to the lifter while self-righting, 7th backdrove the lifter and stripped the servo horn, killing Boom Zoom’s weapon for the first time since its first event and leaving it upside down. Finally, insisting on making it invertible actually pays off! Driving into 7th’s spinner provided a nice self-right, then I was able to control the rest of the fight with some good pushes, and despite 7th throwing its entire weapon stack at me I was able to eke out a narrow win via the judges! The stripped servo horn meant the servo itself was mercifully spared, and a new horn had the lifter working again in no time. This marked another milestone for Boom Zoom, it was the first time it had ever won a fight in a tournament bracket!

My quarter final fight was against Baby Dead Bod, my first horizontal spinner opponent since MK2 and the defending ‘Burgh champion. I slapped the Jungle Man setup on, and got my box rush in well. After knocking BDB around the arena a while, one of its drive motors dislodged and was caught in its own spinner, forcing a tap out. The wedge held up great in this fight, better than I could have expected, and came out with a few chunks missing but largely intact. A hit to the wheelguard bent the mounting through-bolts, not quite enough to lock up a wheel but still a cause for concern. After swapping these out I was ready for my semi-final against Bby Shrekt…

With Shrekt the strategy was largely the same as last time: attack the parts of his front not covered by forks. This fight started badly, with Boomy getting caught on the same floor seam it had trouble with against Vortex and being forced into a head to head engagement with Shrekt. This snapped off one of the lifter fork mounts just like at Rapture, and broke the zip tie securing the lifter elastic meaning I had no means of retracting it. I backed into the wall to try and manually retract the lifter, but Shrekt was on me and roofed Boomy with a shot that killed a drive motor. Shrekt kept the shots coming, damaging a wheelguard and killing another drive motor. Eventually Shrekt landed another shot to the damaged wheelguard and completely ripped it off, ingesting it into the weapon and completely killing itself. I managed to keep my robot moving while Shrekt was counted out, getting me into my first major beetle tournament final. I didn’t feel good about this win, and was on the verge of tapping out while Shrekt was being counted out. It was only blind luck and a bad bit of print geometry that saved me, and I resolved to make sure that could not happen with the next version of the robot. The print had torn away around the mounting bolt holes where I’d really skimped on support material. This was a totally different filament and failure mode to what happened at Rapture, where the layer lines had separated instead. With all that said and done, I had one of the bigger repair jobs I’d ever done at an event on my hands and set to work replacing the dead drive motors and ruined lifting arm, along with fixing a number of other bent bits and backed out screws.

For the final against Grab Crab I swapped out to my control bot setup, ditching the wheelguards and going with the low profile front, intent on giving him as little on me to catch and throw as possible. I also put on fresh wheels for this, as I didn’t know when I’d next be in a final and could use every advantage I could get! Things got off to a rocky start, with Grab Crab getting under me and getting me most of the way to the roof with an incredible yeet. It kept up the pressure and kept me off balance with a series of smaller flips before I was able to turn the tide with a pin and grab, pushing him towards the pit before the Crab reversed by lifting me, and after quite a struggle dumping me down the pit. I wasn’t unhappy with this result, Grab Crab was clearly the better robot and deserved the win, I was just buzzing we’d made it an all non-spinner final, and that I’d managed my first podium place at a big tournament!

Satisfied that the changes from MK3 had made a difference and that the robot was on the right path, I still had a few changes I was considering. For now though I had a robot very much still in fighting condition, and one last event to round out the year: December Dojo!

RoboDojo December 2023

Robodojo Beetleweight fights 9th December 2023

My fights are at 0:00, 8:00, 17:26, 22:43 and 23:54

My fight against Screaming Banshee was a nice one to start the day, no damage, a good pushing match, a gentle pitting, voila. Next up was Icebreaker, and the warmup was well and truly over. Front to front Icebreaker was winning every engagement, and getting around to the sides proved impossible with how well driven a machine it is. Our forks were locking together and protecting me from harm for the most part, but my lifter was getting slowly eaten every time I tried a lift or to wiggle free. Eventually, he took out yet another 22mm drive motor, making getting to the side much more difficult. A couple of flips were a nice consolation, and I was able to hang in there for a Judge’s Decision but deservedly it went to Icebreaker. After this I had a good scrap with Hooligan, where the drum forks were once again put to the test and held up fairly well, allowing me to push it out of the arena, and my control bot setup allowed me to do the same with Toucan in my next fight. This put me in a playoff for third place, with Chucky and Baby Dead Bod. For this fight I opted for a “sword and shield” approach, with forks on one half of the bot to handle Chucky, and a Jungle Man wedge on the other for Baby Dead Bod. Despite what you can hear me say in the video, I didn’t forget to put the mounting bolt in, Baby Dead Bod managed to pull the bolt through its mount with the force of its first hit, ruining the frame rail on that side. With my wedge gone, I got a little trigger happy on the sticks and when an opportunity to pit BDB came along I went full send, pitting both myself and the spinner, snagging 4th overall.

With the frame rail ruined, I once again had a choice: cut and fit a new one, or take the opportunity to redesign the robot like I’d been tempted to after Rapture. I decided this would be a good place to leave MK4, join me next time for the most extensive redesign so far, Boom Zoom MK5! This next one might take a little longer as MK5 is still active, and I’d like to wait until the version retired before I write about it. Until then

[Hoppin (Siôn Williamson)]

Boom Zoom saved my marriage.

[ForkliftCertified (Rob Weston)]

Boom Zoom MK5 Build Diary

Long time, no post! Boom Zoom MK5 has been retired for a while now, but life has gotten in the way whenever I’ve sat down to write about it. This version was a big departure from MK3 and MK4, as the core design was starting to really show its age. The main improvements I wanted to make were:

1. Add more drive power, and make the drive solution more durable.

2. Make the lifting arm more durable and easier to manufacture.

3. Increase the reach/leverage of the lifter.

4. Find a solution to the front armour mount points breaking.

5. Make the chassis easier to manufacture.

A few days in CAD later and I had this!

I’d been inspired by the construction methods I’d seen on other robots at events. I’d helped Scott work on Attitude Adjuster during his deep run at Robot Rebellion 2023, and seeing the way that was built was nothing short of game-changing to me. A TPU unibody with HDPE top and bottom panels, with aluminium hex inserts press fit vertically into the chassis. These provide rigidity for the TPU as well as a fastening point for the top and bottom panels. All this means a chassis which is much quicker and easier to make as it can be 3D printed as a single piece with no extra assembly required (aside from screwing on the lid and baseplate) rather than spending ages cutting multiple panels, making and using 3D printed jigs for the holes that the CNC can’t make, countersinking everything and putting it all together. It’s also much easier to make spare unibodies and iterate on the design going forward, so smiles all around!

For the front mounting, I opted to simply thread 3 M4 bolts all the way through the chassis with a nylock nut on top. With the TPU chassis it should be a lot less likely to pull through than it was on MK4, and even if it does, the chassis is so easy to reproduce it’s much less of a problem.

For adding more drive power, I decided to ditch the 22mm brushed motors. They’d served me well up until this point, but cramming 4 of them into the robot took up a lot of weight and space, and they were breaking with alarming regularity even when they weren’t being directly hit. I instead went for the Repeat Max motors, a much more expensive solution, but I figured I was losing my current motors at such a rate I’d soon make that cost back in replacements I’d be saved from having to buy.

I paired these with some Repeat AM32 35A brushless ESCs as these seemed like a natural fit. These motors are a lot more powerful than their brushed predecessors, so I dropped to 2 drive motors instead of 4 in an effort to save weight and space. For transmission between the two pairs of wheels, I opted for gear drive as I hold a deep mistrust for all things belt-driven. Normally when gear driving a 4 wheel drive robot, builders will put the driven gear between the two wheels as this protects it much better, and offers a small reduction making for more torque/pushing power. This wasn’t an option for me thanks to where I put the servo powering the lifter, so I instead decided to directly drive the front wheel, and use an unpowered idler gear to transmit power between the front and rear wheel. I also 3D printed some guards for the brushless motors to prevent them from eating any wires, and used the Ranglebox Mars hubs to secure the wheels to the motor shafts.

For the gears themselves I “borrowed” the settings from another builder smarter than I, Jack Franklin. The gears were generated by Fusion 360’s GF Gear Generator and are double helical (so they transmit torque more smoothly and self-align) with a 45 degree helix angle and an MOD of 2mm. I used 6mm shoulder bolts for the axles threaded into square nuts press fit into the chassis and oilite flange bushings either side of the wheels/gears to make sure everything rotated smoothly.

With the drive and chassis reworked I moved on to the weapon. The HDPE lifters were being eaten by verts way too often for my liking, and like the chassis they were a pain to remake. I instead went for a single piece TPU lifter, with the top part of the arm braced by a 2mm Grade 5 Titanium plate to add a bit more rigidity.

Finally, I set to work on the front end of the robot. Longer forks were a necessity, as I was being outforked by nearly every opponent towards the end of MK4’s run. I also incorporated wheelguards into the front armour to protect the vulnerable rear wheels, and beefed these up so they wouldn’t be ingested by any spinners like on the previous version. I also fired out a number of alternate setups like a wedge, thick drum forks, lower profile fronts and top armour to complete the usual array of setups.

With Boom Zoom MK5 finished, all that was left to do was take it out for a spin!

RoboDojo February 2024

Robodojo Beetleweight Fights 10th Feb 2024

My fights are at 3:31, 4:57, 11:59, 14:36 and 21:31

My first fight with Chucky was a good test of the waters, I got some great lifts in, won the ground game and managed to fully pick Chucky off the ground and balance it on the lifter for max style points! You may notice I was oversteering at a few points in this fight, this was me struggling with the newly found drive power of the brushless motors, which I would turn down a little for later fights.

My next fight was against Nightcall, which I was able to win simply by flipping the big vert on its back. Sorry Lucas, no way I was letting that thing get back up when I know how destructive it can be.

My third fight was against Synthblade, a really cool crusher also by Lucas. Sadly it wasn’t in a good way by the time I got to it, and a couple of flips were enough to take it out of the fight. I’d put my top armour on just in case, but it wasn’t needed in the end.

My fourth opponent was Baby Dead Bod, in a rematch from Burgh and the previous Dojo, a great opportunity to see how well the changes would hold up. I stuck my TPU wedge on, but found Baby Dead Bod was able to chew through it remarkably quickly and get to my front wheels, where a couple of hits dislodged the wheel hubs from the motor shafts and left the whole robot immobile. Rats.

After some quick repairs I was back in for a playoff for I believe 5th place? Can’t remember. Anyway my opponents were Baby Dead Bod (Again!!) and Ice Breaker, and as the least dangerous robot in the melee I let the other two largely target each other. Baby Dead Bod took a wheel off Ice Breaker who returned the favour by knocking BDB’s link out, letting me focus on the limping Ice Breaker and eventually push both it and the corpse of Baby Dead Bod off the edge.

Overall it was an encouraging first showing for the new version but I was a little disappointed not to get more stick time out of the event, my average fight must have lasted 45 seconds tops. Despite this serious problems with the wedge were revealed. Baby Dead Bod chewed through it like it was barely there, and when it did get through the lack of a groove on the motor shaft for the hub’s grub screw to sit in meant it only had to land a couple of hits before the grub screw backed out enough to kill the drive.

My fix for this for now was to dremel a groove in the motor shaft for the grub screw to sit in, and reprint the wedge with more walls/infill (basically just chuck more TPU at the problem) but while I was confident in the motor shaft fix I still wasn’t sure if the wedge would hold. Moving swiftly on to…

RoboDojo April 2024

Robodojo Beetleweight 2023/2024 Round 6

My fights are at 0:00, 5:00, 12:22, 16:45 and 18:47

My first fight was against Shrekt Force, a scary opponent at the best of times. After some jostling we both ended up with one drive side off the edge of the arena and required an unstick. Once unstuck I was able to flip Shrekt Force over, and from there keep the pressure on until I could shepherd it into the pit. A win with barely a scratch, honestly didn’t expect that!

Next was another fight against Baby Dead body, oh joy. Really though this was a good opportunity to see whether the changes I’d made since last time would help. It ended up not mattering though, after a handful of hits I got stuck under the wall, and in freeing myself oversteered and drove myself out of the arena. From the few hits it did take, the wedge held up a little better but still took far too much damage for my liking, clearly a different solution was needed.

Fight 3 was against Nightcall, and there isn’t a lot to say here, one push and Nightcall was out. It did bend one of my forks in the process though, womp womp.

My fourth fight versus Percussive Maintenance XL was another quiet one really, PMXL’s weapon wasn’t working and it’s an awkward shape for me to flip, so it was basically a pushing match till I was able to pit it. Not a lot learned from this one.

Finally I had a playoff for second place, once again against Chucky and BDB. I didn’t run the wedge in this one as it had already been compromised, and I wanted to keep my forks to stand a better chance against Chucky’s ground game. This worked to my advantage initially as BDB’s weapon went down early and I was able to pit Chucky. After pushing BDB around for a while I got a little too eager, and overcooked one of my shoves which allowed BDB to get behind me and pit me. Oops. That got me third at the event and third in the Dojo league overall, not bad especially as Boomy had only done 4 of the 6 events where points were up for grabs!

Something else good came out of this event too, Sam had decided to retire Shrekt Force, and after discovering its 2mm bent hardox wedge fit Boomy almost perfectly he very kindly donated it! There was no time to get it on the robot though because 1 week later…

Minibeasts In The East

https://www.youtube.com/live/MY8o3BTYVvk?si=qLhuypW5GsPlLyTi

My fights are at 56:25, 3:25:48, 4:50:29, 6:06:31, 6:37:34 and 7:21:05

My first fight was meant to be against another robot that had to pull out, so David graciously lent Grabber Wobba to my opponent for what was basically a whiteboard fight as it was agreed I’d get maximum points for this no matter the outcome. This was my first time in Dave’s arena since moving to brushless drive and I was very happy with how much pace Boomy was putting out, and found I was able to chuck Wobba wherever I wanted for the majority of the fight. Keen to get some stick time in, I took the fight the whole 2 minutes and had a lot of fun in doing so!

My second fight was versus Sniper, Dylan’s very nasty horizontal and reigning Dojo league champion at the time of writing. I slapped the old TPU wedge on as I hadn’t had time to mount the new hardox one and chucked it into the arena. Turns out it didn’t matter! On my initial box rush I the impact broke Sniper’s weapon brace, totally disabling the weapon almost immediately. From there I was free to invert Sniper, grab it with the lifting arm, and pit it at my leisure. Phew!

Next up was a melee with Antithesis and Flick. Two fantastic designs I felt very lucky to share the arena with, Antithesis was able to get a good crush on Flick, and I was able to turn them both over, then drive into them to separate their cuddle. This dislodged Flick’s link, leaving just Antithesis to worry about. I was able to pen Antithesis in around the pit, and after several close shaves from both of us down it went!

Next up was the quarter finals, and a rematch with Percussive Maintenance XL. This time PMXL’s weapon was working so I swapped to my additional top armour just in case. I was very proud of my driving in this fight, managing to avoid every single blow PMXL tried to land and eventually get my first ever flip out of the arena! I think this W left me a bit too confident though, you’ll see why.

Another rematch here, this time against Chucky. Chucky’s forks had grown since last time and Dylan was winning the ground game every time we locked fronts. I was desperately searching for an angle on the side for most of this fight, and in doing so hit the accelerator a little too hard and ended up with one drive side over the pit. A bit of wiggling to try and get free wasn’t enough, and soon it was all over.

There was still the matter of the third place playoff though, against EVA-02. This was another fight where I quickly found myself on the back foot, with EVA having the longer forks meaning it won most of the engagements. It wasn’t able to do any significant damage with the hammer saw, but again I had my top armour on just in case. Sadly though, I done did the same thing again and drove down the pit trying to back into EVA to score a KO.

This was still enough to secure a 4th place finish and a magnificent trophy, easily one of my favourites so far. Not a bad showing but I felt my driving and fight management let me down here. As soon as I was on the back foot in those last 2 fights I started to panic internally, and got a little too desperate to try and reverse the situation which led to me pitting myself twice in very avoidable ways.

On the build side of things, I noticed the lifter was bending quite a bit at the elbow when attempting awkward lifts, which isn’t the end of the world when that protects the servo but also means I’m not getting the most out of the lifting arm. Work to be done there for sure. No immediate changes were really warranted after this but I did cobble together a proper mount for the Shrek Force wedge, which I’d cut down to size and attached to 2 static TPU mounting pods. This meant it was once again ready for the trip down to Chatham for…

Robot Rebellion 2024

Before we get into the fights, a confession. In packing for this event, I’d completely forgotten one of my bags. This was full of all my spare lids, baseplates, lifting arms, and worst of all, alternate setups including all my forked front ends. All I had with me was the new wedge setup bolted onto the robot. This would have spelled the end of any hopes I had of making it past the heat stage, however I had a saviour in Ari, who offered to print some emergency replacements. After talking my partner through sending me the gcode files from my home PC, Ari was able to reverse engineer these into a 3D model then re-slice for their own printer, which had a different nozzle size to my own. A couple of cheeky overnight prints later I had a set of emergency front and top armour! I’d luckily remembered my forks so I was able to slot these in as well, there was a small problem, the replacement parts were bright pink! Due to being unsliced and resliced some detail was also lost, so I had to melt them a little with a soldering iron to get them to fit properly.

Robot Rebellion 2024 - Heat K

My heat fights can be found at 3:31, 15:48 and 25:49

My first fight was against the grand fromage itself, Monterey Jack. This is a glorious build, combining a miniature chainsaw and grabber mechanism to force opponents down onto the teeth. With only one set of front armour made of soft TPU and a long day of fights ahead of me, I was pretty worried about having this fight first.

Monterey Jack got stuck pretty early on in the fight, but in the interest of putting on a better show I freed it from under the wall and kept the fight going. I was able to flip the cheese not long after that, and it didn’t seem to be capable of self-righting so I kept it in that position for a while. I was eventually able to shepherd it down the pit for the win, with mercifully little shredding done to my TPU.

Next up was Bop!, an adorable hammer with some of the best theming you’ll see. Craig had been keeping Bop hidden from prying eyes under a bag in the buildup to this one, and I soon understood why. In an effort to say heck the ground game, Craig had swapped the wheels out to giant foam monster truck tyres, and Tweedy had swapped into a Bop shirt and brought out his 150g cam lifter to act as a minibot. I loved the gamesmanship of this, and it gave an extra layer of spice to our fight, as Bop would now be able to drive off my forks, and the minibot could cause problems trying to high centre me in return.

In this one Bop was monster trucking over my entire robot on more than one occasion, and while I can’t say it was too effective as a tactic it was certainly unique! Tweedy’s minibot tried to go in for some pins but most of the time my drive was enough to sweep it out of the way, though it did get a decent pin on me at one point. I in turn had a lot of fun chucking all 150g of the minibot around, I think I nearly hit the roof with it at one point! Towards the end of the fight my drive began to lock up on one side, but Bop was having drive issues of its own. I later found out from Craig he’d totally lost left/right steering, so all he could do was go forwards and backwards and hope that the robot would go somewhere vaguely productive. This did not turn out to be the case, and before long it had gone down the pit of its own accord, I can’t really take credit for that one! After the fight I quickly fixed the drive side locking up, a shoulder bolt had over tightened and was causing the wheel to bind so I just loosened it off a bit, easy squeezy.

My final fight of the heat stage was against Snek, a very innovative robot using a 6-bar mechanism to act as both a grabber and self-righter. Thanks to the way other results in the heat had gone, I’d already guaranteed my place in the knockout rounds at this point, which meant I could relax a little going into this one.

I had a fair tussle with Snek at first, but the Irish robot was having trouble keeping its front end towards me. I got around to the sides and chucked it around a bit, nearly getting stuck on the pit in the process, before maneuvering it over to the OOTA zone. From there I couldn’t resist going for the big yeet and got it over the wall to end the day 3:0 with 3 knockouts and no significant damage!

Robot Rebellion 2024 - Semi Final B

Into the knockouts we go! My round of 16 opponent was a familiar foe, Digestive. We’d fought at the previous Robot Rebellion, but this iteration of Digestive was a lot more dialled in, fixing the wedge being too low and adding some ground scraping forks to make it a lot more mobile and deadly. Normally I’d fit the anti-vert front armour which has wheelguards and forks, but today due to forgetting those I’d have to settle for no wheelguards.

I found out early in this fight I had the reach advantage over Digestive’s forks, and tried to capitalise on this by staying squared up to him. I was able to get several good flips which left Digestive break-dancing in the corner. It soon righted though and from there I pushed it back into the OOTA wall, where a lift was enough to cause the vert to engage with the wall, sending it up and over for back to back OOTAs for the first time in my roboteering career!

Robot Rebellion 2024 - The Grand Final

My later fights can be found at 15:38, 27:03 and 31:39

My quarter final and a matchup with Grab Crab awaited. Another rematch, this time of the ‘Burgh 2023 final. I was really looking forward to seeing how the improvements would hold up against the crab, especially as Joe hadn’t changed much since our last meeting so this would give a really good idea of how far Boomy had come.

This was a really cagey fight, lots of jockeying for position, flips, grabs, pushes, pins and everything in between. We both had moments where we looked on top, and there was kind of an unspoken understanding between Joe and I that neither of us wanted the pit in this fight. The only damage to speak of from either robot after this was a drive belt of Grab Crab’s that I’d prized off using one of my forks during a particularly forceful shove, and I think that might have been what swayed a split judge’s decision in my favour! This has to be my favourite (at the time of writing) robot fight I’ve ever been a part of, such a great contest from start to finish, Joe really brought it and I’d totally have understood if the decision had gone his way. Grab Crab was a big inspiration for this version of Boom Zoom, this fight felt like a sort of benchmark to compare how the robot was progressing on from MK4 and our fight at Burgh.

I’d already made it much further than I expected, but now would come the toughest test so far: Stratus. I slapped the extra top armour on, partially for the protection it’d offer but also to look more pink and therefore less of a threat.

This fight actually started better than expected! I was able to box rush Stratus and keep it off balance initially, using its significant gyro and high centre of pass to leave it dancing on one wheel the majority of the time while I pushed it around. For about the first 30 seconds or so this was pretty successful, Stratus couldn’t land many serious hits. I even managed to grab hold of one of the stabilisers, which led to some very weird gymnastics when it hit me and launched us both end over end. Around the 30 second mark Stratus got a glancing hit that knocked me upside down, then followed up as I was trying to self right and delivered a meaty hit to the baseplate. This was enough to tear a huge gash in it and peel up the edges to the point where they took my wheels off the ground, and that was all she wrote. All I could do was wiggle the lifter frantically as I was counted out. Womp Womp.

All was not lost though, I still had to gear up for one last fight for third place. My opponent was Ari with Frenzy, the very same Ari who’d printed the emergency parts that had no doubt gotten me this far. No good deed goes unpunished! Going into this fight Boomy was still very much in a bad way. The lifter hinge had been buckled by Stratus and the baseplate was still badly bent, a couple of hits to my rear could have easily high centred me again. My strategy with this fight was to force Frenzy to do a lot of turning, and hope its considerable gyro would flip it upside down. Once upside down I knew its weapon would start hitting the floor, and at that point it could end up in the pit or the OOTA zone quite easily. I had mixed success with this, but Frenzy was still able to score hits and managed to post my robot into a gap in the arena door in one of the best trickshots I’ve ever seen. Some frantic waggling was enough to free myself, and I was able to take the fight to Frenzy. The lifter wasn’t fully opening/retracting consistently thanks to the damaged hinge, but I was still able to get a few good lifts and grabs in. Eventually I was able to open the pit and invert Frenzy, and after some frenzied (hehe) bouncing on its weapon it ended up pitting itself!

I was over the moon to come away with third, especially given my disastrous start to the weekend forgetting to pack those parts. This also made me rethink just how many spares and setups I need to bring to events, I may have been overdoing it in the past bringing at least 2 sets of most setups. I also came away from this event with a concrete improvement to make: REMEMBER ALL YOUR STUFF!!! No serious changes to make off the back of this one, but that’s skewed a little by the peculiar circumstances I was in at this event.

RoboDojo July 2024

Robodojo 2024/2025 Beetleweights Round 1

My fights are at 0:23, 8:08, 15:19, 17:49 and 21:17.

First up (for what feels like the millionth time) was Baby Dead Bod, which meant I finally had the chance to test out my new wedge setup. This was a really fun one, lots of acrobatics from both of us, and plenty of meaty hits. BDB did a number on Boomy, tearing off a rear wheel and chewing up the TPU mounts for the wedge pretty badly, but the hardox held firm and I was eventually able to bounce BDB out of the arena! The damage from this one was pretty rough. I realised I’d made a mistake when designing the wedge, as it fed horizontals right up into the nuts keeping the front armour on. This meant they got a bunch of direct hits and were very hard to remove when the time came to swap setups.

Next up was Delta V, and this was a very cagey one. Our forks were locking together perfectly for basically the entire match, with the slight advantage going to Delta V most of the time. The barbs on Delta V’s forks meant we were getting stuck together a lot, even needing an unstick at one point, and when I did get free I wasn’t able to get around to the sides of Delta V and capitalize with a lift. Props to Jake’s driving on this one, he did a great job of staying squared up, and eventually time ran out for an inevitable JD loss.

Third in line was a rematch against Sniper (most of my Dojo fights are rematches at this point) again a good opportunity to put the hardox wedge through its paces. After a solid few hits the weapon on Sniper went down, and I was able to capitalise with the pitting. My mobility in this fight was hampered by the wedge catching the ground a fair bit, this would need fixing in future for sure. For now though, we move.

Fight four was against Nightcall, in what again seems to be as certain as death and taxes when I come to Dojo. I was once again able to flip it upside down, and this time after a few pushes Nightcall drove into the wall of its own accord and punted itself out of the arena!

This just left a playoff for 2nd place with, you guessed it, Sniper. When it rains it absolutely pours. The wedge did its job again, and I was able to get Sniper out of the arena pretty quickly this time to secure silver!

Overall it was great for the wedge to get as thorough a test as it did. I was satisfied with how it held up, and I hoped a few minor changes to the mounting would be all that was required to help with mobility and serviceability. The result was pretty nice too

The wedge mounts were knackered after 3 scary horizontal fights, so I reprinted them and tried a different mounting method. 6 M5 woodscrews per side, screwing into undersized holes in the TPU. I hoped these would be harder for horizontals to catch if they rode up the wedge, and also easier to remove if they were hit. Let’s see how that went…

RoboDojo September 2024

Robodojo 2024/2025 Beetleweights Round 2

My fights are at 4:44, 9:01, 16:03 and 20:53.

The first fight was against the lovely Heratoss, a flipper based partly on Bigger Brother, partly on the pokemon Heracross, name a more iconic duo, I’ll wait. I wasn’t able to get any flips in, but plenty of pushes, and after a few of those Heratoss went down. Sorry David!

Next up was a rematch against David, this time with Grabber Wobba, and this was a much better fight than our first of the day. David pulled off an insane pit escape at one point, and we had a good pushing match before I managed the KO. Sorry David! (x2)

Fight number three was against Jay and Turbulent Juice! Juice was freshly returned from the US and looked very mean indeed. Things started to look bad very quickly, when Juice hit the underside of my lifter and snapped the zip tie keeping the lifter elastic on, meaning if I got knocked upside down with the lifter open it was game over. I was able to keep the fight alive a while longer, retracting the lifter by backing into the wall but was on the back foot throughout. Juice had me over several times before scoring the killing blow and leaving me immobilised. Props to Jay, I never really felt like I had a foothold in this fight.

Finally I’d get one last chance to test out the new wedge mounting against, you guessed it, Baby Dead Bod. This started very oddly, with the pit tyre being chopped off and left in the middle of the arena by BDB as a nice arena hazard for us to fight around. Neither of us were bothered about it being there so the fight carried on, but I soon wished it hadn’t as BDB scored a big hit to the wedge which completely tore it off at the new mount points. I tried to carry on, but before long Thomas had scored a few more hits and torn off a wheel, leaving me only partially mobile. Rather than risk further damage I took this opportunity to tap out.

This last fight was pretty devastating, the new mounting had completely failed and where BDB had hit the wedgeless side again it had ruined the mounting points, making the chassis basically a writeoff. At this point I’d run the robot for the best part of a year, and was ready to make some more fundamental improvements to the design. MK6 would be next, and perhaps something else alongside it…