Simple motor control

[Dan East]

I'm playing around with a micro-RC car, replacing the rx with a pic to make a simple bot.

I'm using your basic transistor / resistor / diode circuit to control the (tiny) motors. I'd like to add the ability to reverse the motors. Is there a clever way of using multiple transistors to reverse current flow? A circuit that would properly handle exceptions, like triggering both forward and reverse at the same time, would be nice.

This should be the same type of circuit used to drive certain types of bicolor LEDs (the two lead type). I've done quite a bit of searching both here and on google to no avail.

BTW, the Phat Boys micro RC cars are really nice for experimenting. Unlike most RC cards that have actual front steering, this car uses two drive motors, which allows the car to sit and spin in place. Perfect for little robotic tinkering.

http://tinyrc.com/lincoln/Worlds/MicroRC/PhatBoysReview/PhatBoysRC.htm

Dan East

 

[Klaus]

look up "H bridge", either on this site or on Google.
BTW, driving a motor in FWD and REV at the same time is akin to putting a dead short across the power supply (battery) - is that what you want to do??
With a H bridge you can short the motor leads only, which acts as a brake, without blowing the supply fuse.
Klaus

 

[Dan East]

Thanks. I found this:
**broken link removed**

With 6 transistors per motor, I think I'll have to go with an IC.

BTW, driving a motor in FWD and REV at the same time is akin to putting a dead short across the power supply (battery) - is that what you want to do??

That's what I meant by a circuit that would properly handle that - no smoking components.

Dan East