UNO for Bipolar Stepper Motor control

I was thinking that putting the pwm and standby HIGH, that it looks like they will work.

this driver calls out for an application sheet !

1 and 3 are black and 2 and 4 are red ?
but you show 1 and 2 connected as a pair
and 3 and 4 as the other pair.

your photo shows 1/3 yellow and 2/4 brown.

try a test.

connect the two yellows and try to spin the motor. see if it gets stiff.
since it is a small motor, the difference my feel more like a slight cogging,
it should be harder to turn when 1/3 are held together.

when both wires on a coil of a stepper are connected, it acts sorta like a brake.

I tried switching the polarities for the coils to see if they were wrong and the four combinations didn't work. The motor wasn't hard to turn, vibrating, or stepping. No voltages were measured at the outputs from the driver/inputs of the motor.

dave-in-nj: 1 and 3 are black and 2 and 4 are red ? but you show 1 and 2 connected as a pair and 3 and 4 as the other pair.

your photo shows 1/3 yellow and 2/4 brown.

try a test.

connect the two yellows and try to spin the motor. see if it gets stiff. since it is a small motor, the difference my feel more like a slight cogging, it should be harder to turn when 1/3 are held together.

when both wires on a coil of a stepper are connected, it acts sorta like a brake.

Yes, touching the yellow leads together made it harder to turn. Likewise, touching the brown leads together made it harder to turn.

I'm still stuck. :(

edit: Removing the motor leads from the breadboard, the output pins of the driver aren't measuring anything anyways! So there's no way the motor could receive any voltage. So AO1, AO2, BO1, and BO2 are always zero, all the time. All the other pins are measuring the proper voltages though...

Hi,
Have you got those pins soldered to the PCB, it looks like you have just pushed the header pins in without soldering them.

Tom… :slight_smile:

TomGeorge, I haven't, but I have also been measuring the voltages by touching the holes directly as well as the breadboard rows. The other holes on the TB6612FNG board themselves have had their expected values, but that may well be it! I'll solder all of the pins and check! Haha, well that would be a rookie mistake...

:smiley:

It works! Thank you, TomGeorge! Agh, that was such a basic mistake… This was the first time I used male header strips since the pins are soldered on the ICs we use. I wish you could feel how relieved I feel right now. I could not tell you how many simple mistakes I’ve made before in electronic prototyping, forgetting to power the circuit or not bridging the power/ground gaps on breadboards. This one is up there in the rankings.

I also want to extend my thanks to dave-in-nj, jremington, and Robin2. Thank you guys for your assistance. This was my first topic and these were my first posts in the Arduino forum, and your help made it worth it.

Hi, Good to hear, although they may feel secure and in contact, there only needs to be one connection not complete to tip the applecart.

Tom..... :)

cosined: I'll solder all of the pins and check!

You are very lucky that the unsoldered pins did not result in destroying your driver board by briefly disconnecting the power between the board and the motor.

In another Thread some months ago the OP destroyed his board because the pins were only pushed in place and not soldered.

...R

Yikes! I agree then; I'm glad the driver didn't fry. I've had ICs do that before and I didn't have a fun time. I've gained some experience from this imbroglio. Next time I use male header strips I won't make the same mistake.

For those wondering, the code I wrote in the first post worked perfectly fine to drive the bipolar stepper.

Actually, I have one more question for everyone. Why does Arduino provide a stepper library if you can't drive a stepper directly from the microcontroller (because of current draw, voltage spiking, and the voltage required by larger steppers to run)? One solution is to use Schottky diodes to accomplish this as howiam did, but that's not entirely obvious from the stepper library information pages. It seems like it would be confusing for casual experimenters or Arduino newcomers. I guarantee that I would have done the same mistake if not for the electronics classes I've taken.