Let's Make Robots!

Motor controller

I am looking for a basic bi-diretional dual motor controller with a very low price. It must be compadable with a standard breadboard and an arduino. I am looking at controlling a tamiya twin motor (1.5-3v, stall voltage in 2000 mA). By the way,  I am looking making an h-bridge but I have no idea how to make one :(

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Its a popular combination, here is my take, there are lots of others that might be closer to what you want.

Part 1

http://rcarduino.blogspot.com/2012/05/rc-arduino-robot.html

Part 2

http://rcarduino.blogspot.com/2012/05/interfacing-rc-channels-to-l293d-motor.html

Duane B

rcarduino.blogspot.com

L293D is the chip you need. Hit ebay, you can get it from Shenzhen for $2, free shipping.

he may need the SN754410 instead. My question is, how do you power a 3v motor with a motor driver that requires at least 4.5v for the motor voltage?

As mentioned on the SB yesterday, the SN754410 has a voltage drop. Not quite as bad as I guessed, but still a fair share at 5V.

Between the output terminals i put a 470ohm dummy load. I fed 4.8v on both supplies. Set enable high and one input high and the other low. Across the load I measured 3.46 volts, telling us that the SN754410 "wasted" 1.34 volts.

Expect this drop to increase as current goes up.

Actually there is another solution. You can swap out the motors for a better one that draws significantly lower current and run heaps smoother.
http://www.pololu.com/catalog/product/1117
While a more expensive solution. I found it was worth it.

I remember some snippets going by about the Tamya gearboxes sucking a lot of current (more than the L293D can handle) and thus, people were using the SN754410 instead. It sounds like this is the gearbox you have. --For future reference, I think there is a different model of tamaya that uses a higher voltage but sucks less amps. 

Someone please correct me on this if need be.