Need to automatic reverse 12v dc motor.
Application is a shuttle in a saw mill model moving back and forth, driven by a lead screw :idea:

 

Simplest way is to use microswitches operating a changeover relay.

 

I've heard that an H-bridge is good for this. I put "h bridge dc motor" in Google and this site came up - http://www.robotroom.com/HBridge.html

The bridge accomplishes the same things as the relay. I can be constructed from discrete parts out of a junk box.

Alternatives to the microswitch are magnet/reed relay, photocell or similar devices.

Sounds like a fun project - good luck.

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stevez

 

I highly recommend that site mentioned above btw for any robot fans... David Cooks book I think was seriously one of the best Ive read (for a newcomer like myself) into all aspects of robotics, plus as you can see, he knows a thing or two about electronics too.

 

Use L293 Dual H-Bridge Driver Chip. Handles 1A current and is very easy to interface with logic circuit.

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"There is no way to peace, peace is the way!"

 

Aaargh, you guys think all too complicated. Get a windscreen wiper motor, it reverses all by itself

Klaus

 

Actually the windshield wiper motor spins like any other motor. It uses an arm with a ball on the end and some other linkage to move the wipers back and forth.