This was my first ever <120lb robot I've ever built. I've never done the whole RC Airplane/Drone thing so setting up a receiver and baby motor controllers (without firmware) was a first for me. I asked a friend for help and he ended up just creating a from-scratch chaotic board with an Adafruit Teensy.
I knew my v.1 of whatever I'd make would be stupid (and I had only a week or two to will this thing into being while traveling a fair amount for work) so I set a bunch of goals to achieve:
- Must have all electronics easily accessible for tweaking and maintenance
- Must fit the dimensions of this board (roughly 51mm x 81.5mm x ???)
- 3D printed! because car bills were pricey, time is limited and I just got a Mark Two at work (including an Onyx spinner because I want to see what this carbon fibery material looks like if/when it shatters
- Underweight so revisions and additions can be made in the future
- Mad bling LEDs mounted on it so it can have character and flare
So after hours of CADing and sorting out the minimum possible McMaster order I could throw in, I ended up with a good enough CAD.
Being the A+ procrastinator I can be with personal projects, I barely had time to knock this almost fully printed robot out. I assembled everything with dowel pins, plastite screws and a few M2.5s. The motor belting I made out of o-ring cord stock and super glue (it works pretty well... especially with cure time). I decided my wheels had to be ridiculous and cute because I wanted to try out Markforged's nylon dyeing tutorial after printing the STL in nylon on the Mark Two.
If you like these wheels, you can print them by downloading the STL. I lost track of time so my dyeing endeavors ended up waaaay more concentrated than I was planning.
For someone wandering into electronics land, the board my friend built for me couldn't be more confusing to follow or grasp what in the hell is going on.
Once I attached whips to my motors, I was able to lay out all of my electronic guts before setting them into my 3D printed beast.
Next was setting the parts into the robot...
Overall, Rainbow Brite is easy to assembly and I was really lucky my two matches were against even more derpy of robots than mine so I took 0 damage.
Things I learned from this build:
- Overestimate your dowel pin lengths for wheels/spinner bars
- Markforged printers take FOREVER to print (worth it)
- Superglue is going to work on small components better than set screws in plastic
- Makerbot PLA does not make good spinner pulleys (the material started to melt)
- wheels should be mounted onto the chassis base-- I was going to do this but the increased print time for the onyx was going to make me not have a robot in time
- Always have UHMW on hand kicking around in 1/16" to add a bumper on the front for smooth driving (added day of)
- Set your motors to be opposite directions when soldering leads onto them and then LABEL them. Otherwise you'll just drive in circles.
So with that, I was able to compete in Mass Destruction 5 at Artisan's Asylum. My first insect weight (weighing in at 1.7lbs for the 3lb class... significantly less than I planned). For now I won't be revising Rainbow Brite but I'm sure I'll get around to it at some point.