I have an Uno controlling a 4 channel Dagu motor controller with encoder support. Got this a month ago. (It's the red PCB version).
Although it works, I have read that I shall not power the motors before powering the control logic.
But does that really mean that if the controller voltage dies out in the field, and there's still juice in the motor batteries, the Dagu controller will burn ?
I saw OddBot said this might be the case, at least if you powered it up in the wrong order.
[original story: Let's Make Robots]