Valen
Experienced Roboteer
Joined: 07 Jul 2004
Posts: 4436
Location: Sydney
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switches are your best bet for getting it done in time. They will work and are reliable (if your not pulling assloads of current). making a reliable wiper based switch wont be easy, you would probably need to use carbon brushes to try and avoid welding contacts and the like.
Yes it is possible to build a h-bridge with 4 transistors, I don't think its possible for you in your time frame. If your motors are *really* small you might think about using the boards out of the servos to directly drive the motors.
take a look at this
http://www.seattlerobotics.org/guide/servohack.html
don't do it for a motor much bigger than your thumb, take a look at whats in the servo you have and you can probably get away with doubling that size. Provided you never ever stall the motor. For extra points put a fan pointing at the PCB lol (if it gets hot, drive it around and feel it to see if it gets too hot to hold your finger on for a few seconds. Consider mounting a heatsink on it, you can get them from jaycar with fans for about $10 or so) _________________ Mechanical engineers build weapons, civil engineers build targets
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