This bot starts its life as another of my bots’ ends - MITE ants IV…
I had 3 entries into this competition:
A shuffling hammersaw - irrelevant to the story, so will not be discussed, just know it sucked
A 4WD grabber named Farrago, which is pictured below - My first bot where I had tried gears, featuring the use of idler gears to drive front wheels without 4 motors and an electronics layout I quite liked. At the event, I discovered my newly reprinted pinion gear had a flaw, with poor wall generation in the slicer leading to it failing under any amount of force, which led to my amazing idea to just cut off the entire grabber assembly and run it as a pusher. This led to me realising I had a super effective drive base with 35g of spare weight to modify, although I wasn’t sure what I would build. Eventually, Farrago was knocked out due to a combination of my poor driving and my opponent simply having better ground game.
And finally, my first somewhat functional spinner, Uppies, also pictured below. It ran 1000rpm drive, PLA+ and steel forks and a TPU unibody frame, with the 24g mild steel (emphasis on the mild) disc and 1806 motor both mounted to the PLA+ top plate, with a thin channel on the back to route wires and connect the top plate, which somehow was never hit, along with the exposed weapon wires in this area. Uppies managed to advance to the quarterfinals before losing to Ripper remix, once again due to my poor driving and my opponents superior build quality. Even with the positive W/L ratio, I had been unhappy with both the drive and ground game of Uppies for a while by this point, so it was scrapped, with another bot to replace it. I had found a use for Farrago’s drivebase - A gear based 4WD vert
And thus the first CAD for Caustic was born, a branch of farrago, with thinner wheelguards, 4 TPU forks, which would be sprung to the floor by their own flexibility, and the same weapon setup as Uppies, a mount attached to the PLA+ top plate
I had also added a flared front wedge, which didn’t really do much other than look cool and give it a more distinct form factor than the normal square 4WD vert. The electronics layout from farrago was kept, with the brushless ESC to be stacked above the malenki nano.
After printing all components of this design out, only 2 changes were made before competing in January GROCS:
The forks: Following printing, I realised being so thin, they would not mount properly without splitting, so I beefed them up to twice the thickness and removed the barbs, which I realised would only get in the way. To make weight for this change, I removed half of them, but kept their bolt holes, allowing for different positions to match my opponent
The drive: I discovered that due to the flex in the frame, the wheels had a upward camber, which meant the wheels did not contact the ground, due to the gears getting in the way. I solved this by switching to a belt setup of the same wheel size from another bot. This change is not reflected in the CAD, as this was done last minute using pre-existing spares
This is where this build log ends for now, just before the debut event, as I am out of writing time, but I will likely finish this later tonight. Until then, thanks for reading!