Team Oh, It Broke build logs

As I wrote in the Botfest 7 event report, I currently have two new robots ready to fight at Botfest 8.

These two - Honey, I Shrunk the Scrooge and Scrooge McChonk, continue the long and noble line that started with Scrooge McDerp (it lost everything it entered, but in fairness it was a tiny RC stunt car from Smyths with aluminium bolted on as a truly horrific wedge that was lop-sided and didn’t touch the ground) and continued with The Revenge of Scrooge McDerp (an equally terrible cluster of 2 similar but different Smyths stunt cars armed with thin aluminium wedges that accidentally beat a vert while being utterly useless) before The Second Coming of The Revenge of Scrooge McDerp… Again came along - check out the Botfest 7 review for that story!

Honey… is a serious robot for serious competition. I need to do a little work to get the flipper to fully retract after its first firing, which I’m unsure how to fix right now, but otherwise it’s a solid robot. I had a friend design/build it and I can’t remember for sure what it’s printed from now, but I think it’s nylon. Either that or it’s some variant on PLA and I will be making many sad noises when it gets obliterated. Time will tell.

Scrooge McChonk was a silly idea I had to rip the motors from a third different Smyths tiny RC stunt car, put 2 wheels from the original Scrooge McDerp on them (they’re lighter than the wheels it comes with, with the same motor attachments) and build a wedge out of a chunk of foamboard I have yet to fully use. The result was an underpowered, close to the weight limit mess. But it’s FUN. I’m mainly using it to see how the armour handles spinners - if it goes well, I’ll use smaller pieces in strategic areas on future builds. I’m assuming it will not go well.

This does leave me with the option for a third robot. I have nothing that is worth entering, so either I leave it at 2 and have less arena time, or I come up with a third design. I’ve been mulling over a Killertron tribute bot, built entirely around the BBB drive system and the metal servo (plus extender), but with the Ranglebox M10s. I’ve designed bespoke hubs for these, using various tyres so different designs can have different hub sizes. These range from 30mm down to 20mm, the smallest based on the smaller front tyres of the most recent aforementioned tiny Smyths stunt cars.

Quick aside, feel free to ignore from this point on, there’s nothing really present/future relevant after this point: this model in particular has become a bit of a tradition at Botfest, first being used at the Milton Keynes AWS in 2020 as The Beatle… Waits, which wouldn’t drive straight and were shamed into the pit in both their fights. One was entered into Botfest 4, modified into the utterly atrocious When Unicorns Go Rogue (which got my first ever win, because I got stuck and my opponent freed me, then got stuck and we learned I didn’t have the torque to return the favour. Not proud of that one!). There’s also another covered in bits of an old boiler cover called Rust-Bucket, which is very top heavy, has a 3mm aluminium front wedge that is FAR too steep, and ended absolutely every visit to an arena (not just fights, it’s done this on its own when testing too) lying on its face.

They returned as The Sacrificial Lambs when I was an entry short for Botfest 5, and somehow survived absolutely everything that hit them. They lost every fight, but they wouldn’t die. They were meant to. They were stupid. But they’ve got a real love for life. So they were added to the spinner rumble at the end of the day and everyone was given clear instructions to kill them. The buggers all survived, except the one driven by Team Bunny’s Sakara, who successfully got hers killed. She still has it as a trophy. The others came back for 6 and 7, and while still not winning, WILL NOT DIE. So now they get used for parts for equally useless but slightly less silly designs.

When Unicorns Go Rogue is… somewhere, but I can’t find it right now to get a photo and frankly, I never want to see it again anyway. So here’s a couple of photos of the far more impressive Rust-Bucket!


You can see the bare bones of the stunt cars that the Lambs were made from, they were far less modified than this one was.

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So, because I am an idiot and it’s funny, I’m throwing together my first beetle. It is as yet unnamed, and will be a literal box on wheels. I’m doing this on the cheap, so the only thing I’ve bought for this (ages ago) is the safety gear. The 4WD system is bodged together out of two drivetrains from old RC cars, and the ESC/battery are the same as I’ve been using in my ants. I don’t expect any success, but it’ll be fun to play with something bigger for a change.

The drivetrain:

I also have my third ant for BotFest 8 on order from Ranglebox, so hopefully that arrives soon!

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So… the beetle project went both brilliantly and disastrously. I’ll cover that first because it’s the first time I’ve had an entire crowd behind me, and I’m proud of that!

So for those who don’t know, BotFest 8 trialled a sportsman beetle tournament. I, technically, entered a beetle named Y. Which on many levels was a valid question. The drivetrain mentioned above did not see action, largely because I managed to break one of the motors (but also because I ran out of time to cut the chassis, having forgotten to leave space for the motor housing as well as the wheels to protrude, so… yeah, go me). Instead I ran 4 N10s, which helpfully were mismatched. The rears were faster than the fronts, but everything was underpowered. It was an ant internally, with the link and LED wired in. Except the LED was dead weight because on the day it wasn’t working - seemingly having blown during testing. Might need a higher rated light for next time!

Y testing the night before:

Y looking extremely professional from underneath:

Y from above - note this is after the tournament, and the damage is barely visible. Probably not at all in the photo. Death Grip BW barely scratched the aluminium!

So as mentioned, I went into the QF battle (there were only 8 of us, so that sounds like an achievement it isn’t!) against Death Grip BW. It lasted the full time, and the clear crowd favourite was robbed by a proper beetle that was twice the weight of Y, had an actual weapon, and drove faster than a tortoise in a coma. All clearly unfair advantages that should have resulted in a DQ, of course. Y was robbed! But it was a fun couple of minutes watching this badly assembled box amble around the arena, including a few head on attacks on Death Grip (which shockingly caused no damage, clearly the sharp corners weren’t sharp enough) which is where the scratches came from as Death Grip failed to make a meaningful impression.

Y was later flipped by an antweight.

Now, onto the serious robots.

The first robot to fall was Scrooge McChonk. Testing before the tournament, largely for my partner’s benefit before her first ever event, one of the scavenged motors died. I assumed it was my bad wiring, so I went over every connection, detaching and reattaching it. Now both motors were dead. Hmm. Last minute withdrawal it is then! In a way that was a blessing, as it meant a full ant-worth of spares, allowing the Rx to be stolen later for my partner’s robot after hers got dismantled in a fight against Rob Weston. None of us know how exactly the Rx took damage, it was never directly hit, but something wasn’t happy.

Of the two robots that actually did fight, Honey, I Shrunk the Scrooge was the one I had the most faith in. A slightly shrunk version of the flipper that made the final 8 last year, this time made of PLA-CF rather than regular PLA, what could possibly go wrong?

Yeah… lots, actually. First fight? Iceberg. One flip in, and the flipper got wedged half open. Still not sure why, it behaved perfectly well after the fight, just not in the arena. But I took some big hits. No serious harm done, but even so, a bad start that ended with me stuck on my back on the arena wall.

After that I’m unsure of the order of my fights. I took on Ikari, who managed to flip me and demonstrate that I could no longer self right. No idea why. Again, this wasn’t a problem before, so… yay, my robot just likes being a pain. I then fought Thermidor Lol, with James avenging the Little Sytes I dispatched so well last year with The Second Coming of The Revenge of Scrooge McDerp… Again. A quick pitting wasn’t what I wanted to see! At least those two fights gave me no damage.

So you may be noticing a theme here, Honey comes in as a theoretically strong robot, and lets itself down in every conceivable way - if my driving doesn’t get there first. Coming into the final fight of the heat, knowing this was purely for pride, I faced Ember. I knew I was doomed. That spinner scared me more than any other on the day - and that’s in a field that included Dissector! More on that later…

So, with no ability to self right, still bearing damage from the last vert, I absolutely dominated against Ember. No, really. Stop laughing at the back, I can see you. The spinner wasn’t working, so I just had to flip it and that’s the end of it. Redemption? Nah, the upgrade clearly didn’t work. This is a one time entry, and next time I think I’ll revert to what I had last time.

The damage:

Nothing terminal, but looking closer at the chassis I’m wondering if the crack is enough to reduce the flipper power to the point where the srimech didn’t do its thing. Luckily it still worked aggressively, but… yeah. Don’t do crack, guys.

Now, I teased a third robot before, which I was still waiting to receive from Ranglebox at the time. I present to you, Scrooge McKillertron!

One of my aesthetically best builds, but everything else was a disaster. The base was only 1mm thick, so extremely flexible, and the whole robot weighed in at 170g. Which, it turns out, is actually too heavy even for the more relaxed BotFest weight limit. Oops. Time for some Razer holes. Which did not do as effective a job as I hoped, so it ended up looking like Razer itself gave me them:

My poor butchered baby! To add insult to injury, the switch broke and I had to leave it turned on after tech checks until the first fight. Which thankfully was against a nice, easy opponent, which you may have heard of. Dissector. The switch broke again before any contact, so I let Dissector get a couple of bites before tapping out. A new switch was kindly donated, leading to a more functional robot for the rest of the day.

OH! I forgot to mention. I set it up upside down to show off the axe’s self righting capabilities. The axe promptly sheared. Before tech checks. Another axe, from Kit 3, was donated to the cause.

Fight two? Another spinner. Great. This time, Lucy’s Lafiel. Which utterly failed to do its thing, and I pitted it pretty easily. This wasn’t a deserved win, but it’s the best I got all day so I’m taking it.

I feel like there’s a fight missing from the videos I have, so no idea what happened against Shego. I lost, that’s definite. But finally I faced Courtesy Bar, loaned to Theo, who claimed he went easy on me. He either lied or has no idea how much damage a vert can do. The lid was bisected, a chunk was removed from the base, and the axe arm came off the servo (although that happened almost every fight, I had to remove the bolt from the servo for weight purposes…)

Next time I’ll bring this back, but I’m switching the axe for a flipper. And I’ve redesigned the lid, so hopefully I won’t have to go crazy with a drill.

The damage (and replacement axe):

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Bonus pics: I bought a new hacksaw purely for Y, because the frame of the standard one limited what I could cut.

Before:

A really nice tool, if a little flimsy.

After:

It literally got beaten by a flat-packed box. Not sure what the next tool will be. Might have to use a power saw.