In the latest Make: Robot Build Newsletter, Matt Mets wrote a piece introducing motor controllers and linked to an ITP article on using an L293NE motor controller. In the Robot Build area of the MAKE Forums, Alan Kilian pointed us to this other excellent tutorial, Control Your Motors with L293D, on Let’s Make Robots. It has very clear breadboard images and shows you, among other things, how to add a few capacitors to your circuit to smooth out the current.
Control your motors with L293D
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8 thoughts on “Robot Build: Using an L293 motor controller”
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I have an interesting conundrum in which the motors that drive my gearbox (the ones that came with it) are 1.5-3V, and my MCU requires 5V. I’m going to be using a MintyBoost to drive 3V up to 5, and a separate 3V source for the motors. I’m just hoping that using a 5V signal to activate my H-bridge to run 3V to the motors doesn’t cause a problem. I can’t remember the math for transistors, but I’m pretty sure that having a higher voltage at the base than at the collector should just throw it all wide open. Guess we’ll see.
Look at the datasheet for the transistors in your H-bridge. Look for Vbe(sat) Aka Voltage, base to emitter. It will usually be 0.7v. So you will have to be at least that much higher in base voltage.
I’ve had better success with the L298N. I kept burning up L293’s.
Also, I have some PD control code for both of these drivers here:
http://subzonepen.blogspot.com/2009/06/dc-motor-closed-loop-pd-control-code.html
clicking on the link above “using an L293NE motor controller” shows lots of php internals which i presume is unintentional…