Little Stomper

thingiverse

This is a robot platform with forward-rotate control using a common yellow dc gear motor for each control. The non-circular rollers will make the robot stand alternately on the rollers or on the rotator ring, which enables pure forward or pure rotating motion at a time. With rotary encoder on each motor (not implemented yet) the motion could be controlled more precisely, for example every forward move always end with the rollers in 'up' position. There is space for 2x 18650 battery holder in a tight fit. For the controller, I have not designed a PCB holder since I found cutting and gluing cardboard is much faster and cheaper than designing and printing it. Here I use Arduino Nano with custom carrier PCB and Bluetooth remote control. Arduino Uno holder and top frame with ultrasonic sensor holder are not tested. Gear ratio: rollers: 8 : 15 rotator: 8 : 65 Video: https://youtu.be/Z3O_GmBhaHg Screws needed are all m3 size, with length: 30mm (+ nut) x4, for the motors 10mm x 9, for attaching ring gear to the ring, middle gear axle, and attaching anything to the top frame. 20mm x4, for roller axles Screw holes: motor holder: no thread, 3 mm diameter roller holder and gear holder: thread cut with m3 size hand tap middle gear and roller: no thread, 3 mm ring gear: thread cut m3 ring: no thread, 3 mm top frame: thread cut m3 The curved part of the rollers are covered with rubber sheet (bicycle inner tyre) for better traction. (Do not mind the two color roller, it was filament change mid-print because I was out of filaments)