Just a PipeDream

It all started when I was super ill over December incidentally watching loads of old seasons of Battlebots and realised i’f not seen any big wheeled ant’s. The 4" cube rule was still a thing back then , but some quick sketches sugested it would be possible to make a 4" cubed vert spinner. Having never built anything more complex than a front flipper before, my deseised mind set to work .

The hard part was surprisingly hard, figuring out how to transfer power and signals from one side of the bot to another, as well as making a frame stong enough to absorb hits without gnerally letting the side down. (This last part was only a partial success, more on that in part 2).

Fast forward a month and i’d figured out the answer: Needle bearings and a hollow metal pipe, attached to the chassis in a couple of points. Then offset the drive motor and use various cogs to directly power the weapon. Easy right ? Well. another month of iteration and i’d got a working mockup, based around this sort of design - with a lot of help answering stupid questions from OOTA, Joe, Hop, Rob and many many more. Did i mention this the first foray into brushles motors too? well. hello :wink:

Outer shim washers stop the PLA melting, 12/16mm needle bearing holds the weapon and weapon cog, sandwiched together with horizontal grub screws, driven by a 1404 3kv brushless motor with a reversible BBB Drive motor, so the weapon can spin both ways. All this sits on a steel, then later Aluminum pipe.

Herein lies another issue. Making the pipe fit was impossible in my shed, so over to the East Essex Hackspace we go and enlisted the help of John, the local Old fella who can use the lathe and digital mill, who knocked one up in a jiffy after a few sarcastic comments about my 0.25mm tolerances being a bit sloppy :slight_smile:

Spot the difference:

The rest of the chassis is a simple box with battery on one side and Mk2 malenki on the other. Simple enough. it took a few iterations of ebay ordering to get some decent 180mah 1s batteries to solder up for the power side and a few similar motor iterations to settle on 100rpm N10’s. power flows through the middle to the malenki and drive comes back to the N10. A JST allows for the battery to be removed for ‘safety’ though due to space I have to un-solder at least one motor to get the weapon assembly appart.

The next challenge was wheels - first tests with 3 part TPU/PLA/Stud wheels were wildly unsucessful and impossible to control, so more grip’s needed - eventually I settled on casting silicone mixed with paint and cornflour directly onto the PLA-ST hubs, giving nice grippy, and hopefully tough wheel, which is unfortunately a massive target for anything that gets close (more of this in part 2 as well!!)

Finally, the weapon was provided via Hopmeister’s Hardox Services inc. with a 18g light bar, 24g heavy bar and 30g disk making it off Fusion in time. though earlya ssemblies shows i only ahd enough weight was the steel middle for the lighter bar, i figured it’s better to have hardox and not use it imemdiately and work towards it :slight_smile:

So here we are - it goes together - it makes weight. I’ve got a test box… how does it do ?

Apart from one small problem of newtonian physics kicking in on spin-up and it tipping forward - solvable by adding some weight to the back (bolts on the support legs) - it actually, finally, improbably works. Up to this point it was a perfect 100mm cube, but as the BBB team just ditched the cube rule, i could stick these support weights a bit further back to try to offset a fast spinup. The whoel weapon should get to top theoretical tip speed of ~150mph in under 2 seconds at this point.

There were points in this stupid 3 months journey it nealy went in the bin, but bots like this are a sickness.

Then SCAR finally comes around, and it’s off to the beautiful north to have a scrap. How does it do? Well, i’ll tell you. Tomorrow.


Well, now this forum is on a watchlist for sure with that thread title.

Robot is excellent, love the amount of smart problem solving in a small package. Hope the gears hold up!

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Awesome as always Martin! (Btw, I have your locking bar, you left it at SCAR!)

Well, now this forum is on a watchlist for sure with that thread title.

Inretrospect that is not a great idea :smiley: I’m working on a new one.
and thanks
and Thanks Sion. see you in a few weeks bud.

Sooo I promised you a bit of a recap from SCAR and in 4 words it went:

“The Wheels Fell Off”.


But really, it did OK. First off the bat i got drawn against Sam Price and All Star. A termendous first fight for a brand new bot. The fight was fun though. Early on i manged to top the side of his weapon mount off and nearly dislodge the whole thing, but couldn’t capitalise, and eventually he manged to shred & remove my wheels leaving little bits of stringy PLA wrapped around the central spindle and generally in a sorry state:

Still, scored one moral victory point for breaking a frame. Sorry Sam! What this doesn’t show is the internal bulkhead where the weapon mounts shattered as well. A bit of Superglue patched it up for the rest of the day but some forces came in at some angle and need to be dealt with.

Fight 2 against Stewie just couldn’t drive the thing and went into the pit. twice. Once without countact and a second time after one solitary hit on the side of Stewie. Consolation prize was the damage that one hit did. a few more would have caused trouble.

Fight 3 against the other Sam (not this sam) which was at least short, one hit punted out of the arena. where a wheel fell off.

This itertion’s Final Appearance was in the Gladiator rumble, where the wheels fell off after about 10 seconds.


So for a brand new bot 3 ok fights was fine. nothing fatal is wrong with the design. Except the wheels keep falling off. Post event teardown shows I only had the weapon set to half power eg about 75mph tip too which isn’t brilliant.

Rob (Boom Zoom)'s lumberjack gave me an idea to use super-light packing foam with TPU hubs instead of the heavy fragile PLA/Silicone ones which will hopefully be ready for ORCS on saturday (June 3rd). And with the weight saved on them (about 20g seriously) i’m able to upgrade from the 18g bar to 30g disk to give it a bit more cowbell and still ahve spare weight for counterbalancing.

I’ve a bit of a dream list for the future, but ran out of time for this weekend:

  • Repalce the gears with Pulleys and O-Rings
  • Upgrade to a 1806 motor
  • Cut the battery to a 150, or even a 3S 120 if I can ever find cells.
  • RePrint the Chassis into something fancy :wink:

Fingers crossed eh ?

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Hello my loveleys - it’s been a while since I’ve posted anything ant related. Partly 'cos I ended up building a beetle over spring/summer and that’s taken a while, with some success. Partly because this particular silly bot never worked, got blown apart again and sort of tilted. But everyone here is lovely and deserve pics of bots before they get trashed on Sunday.

I’ve Re-Cad’d and upgraded MouseTrap, my 4wd Front Hinge flipper to be a bit of a mid-life crisis bot, I absolutely adore this one. PLA+ Chassis, TPU90 front, 4wd N10’s, Malenki & KST215 servo should be in fine yeeting form for the PLANTS 2v2.

Then forgive me fathers, for I have sinned and built a Vert. Definitely only to test PolyMaker CoPA Nylon filament, not for the sneer joy of hitting bots with massive spinning weapons. I’ve heard it’s fun. Can anyone confirm? The working name of this is “Just a Tribute”. But a tribute to whom? It’ a little shy boy, so photos are hard to come by.

The internals are an absolute nightmare…

This should be in the main comp on Sunday. See you then !


Ants are looking great Martin. Looking forward to seeing them in action at the weekend!

aww thanks buddy it will be good to hang out and maybe fight.

Won’t be able to fight - I’ve got a family thing that afternoon, but will probably pop by to show my face and see what’s up for the first hour or so

Awesome dude looking forward to hanging out with the (robot) family :slight_smile:

I’ve been through a full iteration step with each of these again after the BBB Pub. The Undercutter/Control but now undercuts more and wastes less weight on the wej (down from 35g to 15g). The vert doesn’t waste weight on the metal scoop and instead uses a replacable front end, allowing for my chassis strength after it got eviscerated. The flipper is mostly the same, but may have a spicy rear end to liven things up.

Here are the kids, vibing for haloween: