how can I control 2 cordless drills with 1 potentiometer

I would like to use 1 potentiometer to control 2 cordless drills. I don't have a potentiometer yet but I do have the 2 drills and a arduino uno. The drills are 2x Einhell BT-CD 10,8/1 Li these are not great but they are cheap. So my question: how can I power the 2 drills at the same time/at the same speed?

Thanks

Hello,

I could not find what type of drills they are but i'm assuming they are dc (battery powered). To control them you need to know how many amps the will use up. I would assume less the two amps. If that is the case I would recommend a motor driver like the one posted in the links below. To power them Just take the batteries out of the drill attach them to the motor driver and your good to go. The coding to control them with a potentiometer should be easy but you should ask for help for that under "programing."

http://www.robotshop.com/productinfo.aspx?pc=RB-Dfr-19&lang=en-US

Well, you won't get EXACTLY the same speed but you can connect two transistors or logic-level MOSFETs to a single PWM output pin.

Alternatively, you can connect the transistors to two different PWM pins and use software to set them to the same power level. This would allow you to fine-tune the speeds to get a more exact match.