yeah, i forgot to mention a V-thing to guide it onto the charge points, its an easy obstacle to overcome so it slipped my mind. i wouldnt do speedbumps because as soon as it goes up then a wheel dips into the slots, it will be left with the wheels off the ground and the chassis dragging ont he top of the bump. the LED bulb would be simple, wire it so that the LED and the charge leads are both on the same power source(be it 4AA or AC charger...) much like when you do the direct charge mod to a zipzap controller it will turn off the LED and that means it is charging. the timer could be a 90second limiting thing(sorry, forgot the name) kind of like the one you replace in a controller as suggested on
www.questformadness.com as soon as the led turns back on i think that would be the cue to go