Motor Driver: Accepting Failure; Moving On

I’ve been avoiding having to post this, but my motor driver is not functioning correctly. I have confirmed my test software is sending signals using my DrDuino test shield, but after poking around with my voltmeter, I find that the motor voltages are bouncing between 7v and 4 v when they should see something similar to 5v to 0v.


Luna trying to troubleshoot.

My motors are 5v stepper motors, so hopefully I haven’t damaged anything. I wonder if my semi-randomly selected diodes are causing the issue. My 5v converter chip that was working before now seems to put out 9v too – I can’t figure that out, not without pulling parts off and trying again. I’m not surprised, as I never got to breadboard the arrangement.

Adafruit to the rescue!

Adafruit to the rescue!

Rather than mess with this any longer, I’ve decided to go the easy route, and order up some Adafruit H-Bridge motor driver boards. I bought two for $4.95 each, making my two feeders independent of each other.

After some simple soldering, I hooked up one of the drivers and it spun my motor! Not very efficiently though, and cranking up the speed just made it jitter. So I hooked up some lights to the motor, and found it was behaving unexpectedly.

I found this odd, but thought that maybe I had used the pins out of order in my program. So I took a look at the light pattern, and rearranged my input pins to follow the correct pattern.


However, the output on the motor driver did not match this. The motor driver is working correctly, as found in the datasheet for the driver.

First, let me explain. The motor driver can drive two DC motors (motor A and motor B), or one stepper motor. When a single motor’s inputs are both HIGH, the output goes to LOW as this is how you would stop a DC motor. The intention then with a stepper motor is to use the inputs exactly how I had initially coded the inputs. The change I needed to make was to cross the stepper motor wires in the same order as my simple sketch above.

Then voila! Motor turns!

Check out this post for a quick wiring schematic and my test code!

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