Just saw the arduino debate. There's absolutely nothing wrong with using an arduino in a robot, they are fantastic pieces of kit. It's fairly well known by the tech checkers that my axe is arduino controlled and I've never had issue.

As Max pointed out I control the axe in my robot with an arduino nano. The arduino let me input time restrictions, double failsafes and stall prevention (With an option of limit switches on top). Frankly my bot would be more dangerous without it (And even more fire prone :P ). All my arduino is doing is acting as an interface between the receiver and the TZ85 watching the throttle and gear channels turning that into a throttle signal to a (home hacked) TZ85. I intend on doing the same as PINSKI is here with an arduino turning a lifter into a big overpowered servo. I could use tiny ATMEL or PIC chips (and infact have a small tube of ATTINY84's on my desk right now) but I find it easier to just shove a nano in, and the reprogramming on the fly is easier. Plus afterall the chip in an arduino is the same as a TZ85 and after hacking what's really the difference?

Sorry for the hijack. The robot is looking excellent and I look forward to seeing it done, 4 bars are a favourite of mine!

To echo Kane, a switch to turn everything off is a great idea, it's easy enough to have the system look at the gear channel as a can/can't move signal.