Vermes
Advanced Member level 4
Design Assumptions:
- minimum (preferably zero) cost
- rear-wheel drive
- steer front axle
- 3-speed gearbox, sequential (3 speeds forward and three reverse) without having to change gears at each change of direction
- large wheels, low center of gravity
And the rest of the construction.
This modes hasn't got any chassis, all of the construction is based on a thermoplastic adhesive.
1. batteries and the motor (from a dryer)
2. wheels made of a plastic tube covered with rubber from the inner tubes
3. differential
4. turn mechanism
5. and a simple box to cover all the mechanics and electrics
About electronics:
The remote control module is from a mini-car. There is a forward-reverse relay added to it, the turn motor is connected directly with the board module. There was a small problem: there are only 4 canals, but 6 are needed. Therefore if the left and right turn are used in the same time, the gearbox is turned into a lower gear, and if forward and reverse are used in the same time, the gearbox is turned to a higher gear. The module from the mini-car had a blockade for using left and right, and forward and reverse in the same time – it was bypassed using a 100 micro F capacitor with a parallel “unloading” resistor.
The motor of the gearbox changer is identical to the drive motor – it's turned on by loading the capacitor (ahead of each gear) and stopped by a relay, that switches the capacitor to unload.
Link to original thread with films - Zdalnie sterowany samochodzik z 3 biegową skrzynią biegów