Cordless Drill Mod

Hey guys,

I was wanting to know if anyone had any ideas for a project I was thinking about doing with a spare cordless drill I have laying around.

My idea for the project is to use the drill as either a motor drive, or a steering wheel drive for automatic steering on a vehicle (small childs plastic atv thing possibly).

For either of these projects, I believe I would need to hack into the motor and be able to control the drill speed and/or torque.

I assume that the battery terminals go straight to the motor terminals ( I haven't opened it up yet, as I am still trying to see if this is even possible).

My idea is giving a 12V supply to a motor bridge, then use an arduino to give the motor bridge a PWM signal to modulate the drill's speed, and have the output go into the batter terminals.

If that all seems do-able, then I'd add some sort of encoder to the motor for feedback reference.

Does this seem like a do-able project, and am I missing anything, or does anyone have a better idea of how to do this?

I assume that the battery terminals go straight to the motor terminals

Almost certainly not: there's at least going to be a switch in one side the path. If it's variable speed and reversing (which nearly all are these days), the battery will be connected only to the speed-control circuit.

The biggest surprise waiting for you will probably be how many Amps that motor will suck up: plan on using something like an RC car motor speed controller, instead of a typical motor shield. Or look into modifying the drill's own speed control circuit.


Ya, I found some time to open it up and found the speed control circuit. I'm thinking that modifying that circuit is the way to go. Thanks for the help.