[Kevin Sevcik]

So I've had a brainstorm that I'm both anxious and terrified to try out. Those Tetrix motors are expensive after all. All this requires is a standard 4-way light switch and a little faith. For those not in the know, a 4-way light switch takes two inputs and swaps them back and forth. Switch up and A->1, B->2, switch down and A->2, B->1. So, if you have an appropriate drive mechanism, one creatively wired 4-way switch should be all you need to reverse your robot and bring it down at a moderately controlled speed.... Now, stay with me here, cause this is a little crazy.

To get a 4-way switch to reverse your motors, you'd wire battery + and - to the input side, and motor + and - to the output side. Switch up, motor goes one way (up), switch down, motor goes the other (down). Wire both motors to the output, and they both get reversed. Rig this to reverse the motors at the top, and after your minibot's meteoric rise to the target will come a much much more meteoric plummet to the earth.

So how about this.... Wire one motor to the 4-way output normally. It gets reversed at the top. For the second motor, wire ONE lead to the correct (upwards) 4-way output. Wire the other motor lead straight to the correct battery lead. When the switch is flipped, this second motor is gets shorted to itself across the switch, causing it to regen brake, thus slowing down the minibot a rather good bit.... I think. But this circuit looks like it might have some... interesting... dynamics, as the second motor is in the return current path of the first motor, which I'm having trouble thinking out properly at the moment. So don't try this at home yet until I work out whether I'm being a little too clever here.

To the electricians in the audience, yes, you could hook the second motor up to its own 3-way switch to isolate it from the circuit, but that's a whole extra switch's worth of complication and weight. We're on a strict diet here, man!