Lego power functions

I remembered a long time ago my parents got me the Lego Robotics Invention System. Then years later I traded the computer for something. But I still have all the gears and wheels and everything. I thought it would be simple to integrate the motors to arduino. But I went back home and found that the motors are gone too, I must've traded them as well. But I still have all the gears and wheels. The motors cost an arm and a leg on ebay but there are new ones that are about $8 new. They appear to be compatible with my gears and wheels but they use a 4 wire system and I don't want to invest in them until I know I can use them with arduino. The only info I could find about them is here. It says there is constant power to the motor as well as support for the past systems. I guess that means with some experimenting I could at the very least get them running like the old ones. But I would first like to get some advice as I have never dealt with motors. And if anyone has more info on these motors I would appreciate it. Should I have any trouble getting these things running?


This might help

They also have these

So it looks to me that you simply provide the motor with 9v, then use a 9v signal on either c1 or c2 to power it forward or backward. This seems to also mean that I would not require a motor driver to drive these things, just something to switch 9v.

Does that sound correct or am I missing something?

Yes that seems right. They also have servos that i linked to

Excellent... Unfortunately I can't seem to find the servo sold on it's own. But these motors will add a lot of value to the old box of legos I have laying around. Thanks.

No problem. I found them here but theyre expensive

Yeah I eventually happened upon those but I may wait to drop that much cash. I'm getting 2 motors so I'm ok on steering at least for now.

Yea. I messed with NXT before i found arduino. I have like 8 of them.

Ok update, this was not correct before. I believe that the motors are driven through the two center pins just like any other motor and still need a driver. The other two pins are only for passing 9v through to other devices.

I know this is an old topic... but I have created an simple arduino shield to interface with power functions, so if anyone still sees this thread you can get one here: