# L293d h-bridge and a 12v 350mA bi-polar stepper motor. How do I hook these up?

So first I’d like to admit my knowledge of Arduino and electronics in general is very little-- turns out that the Sparkfun Uno Beginner kit didn’t turn me into an expert.

From research, and what I can gather, I should be able to control this stepper motor:

with one of these l293d h-bridges:

From what I understand from this diagram:

Pins 1, 9, and 16 connect to 5v, which I can get from the Arduino

I can then hook up the inputs, let’s say I do pin 2 from the L293d to Arduino pin 12, pin 7 to Arduino pin 11, pin 10 to arduino pin 10, and pin 15 to arduino pin 9, right?

And with that, that means I would hook up the red wire - coil1+ to pin 3, the yellow wire - coil1- to pin 6, the green wire - coil2+ to pin 11, and the gray wire - coil2- to pin 14. Am I right here?

Pins 4, 5, 12, and 13 get grounded

Pin 8, gets 12v at 350mA. From my understanding of current, that means I need 34.28ohms (which I can round up to 35ohms) worth of resistors in order to not fry out, but I don’t understand where to get the power from? AA batteries are 1.5volts, can I hook up 8 of them in a series with 2x10ohm and 1x15ohm resistors and then run that as the power? would that work?

Would this work? And how do I know the gear ratio? This thing is rated to do steps of 1.8deg or 200 steps per revolution, but it doesn’t say if it’s a 1:1 ratio, and from what I understand I have to declare the number of steps in a revolution to the Arduino in order to calibrate the motor, right?

I’m totally lost, I think I know what I’m doing, but really I have no idea, could someone please help?!

Just made a diagram on Fritzing for ease:

I'd experiment but I'm afraid of frying my chip or my motor.

How about a schematic? That would make it a lot clearer. With the fritzting picture, there is no info as to what the chip pins are, so one has to look up the datasheet just to start.

So long as each of the two windings goes to a separate H-bridge (same enable pin), then you're good. With 0.35A your chip won't get too hot as well (it will get hot, just not too hot).

MarkT: So long as each of the two windings goes to a separate H-bridge (same enable pin), then you're good. With 0.35A your chip won't get too hot as well (it will get hot, just not too hot).

Hey Mark,

Will hooking up the 8 batteries together and running it through 35ohms of resistors (like i diagrammed above) work like I diagrammed above??

Why don't you just read this:

I have driven this motor with an L293 without any current limiting resistors with a 12V motor supply and the motor runs slightly warm. You motor is only 1 ohm less per winding so it should be fine. There is a wealth of tutorials and schematics (and code) for driving this kind of motor easily found using Google.

Hello, I have a 5V stepper bipolar with L283D and connected to all 4 pins =5V - my motor is heating up a bit - why ? any suggestions?

Unless you post a schematic of your wiring or a point to point wiring list it is not possible to answer your question. You have not posted a datasheet for your motor or a link to one. We don't know how you wired the L293 power pins. We don't know what you are using for a power supply. In fact, it would be accurate to say we know nothing about your circuit other than it involves a motor (specs unknown) and a L293 (wiring unknown).

Is it any surprise my answer is: "I have no idea "