No output from High Power Motor Driver 36V9 raspberry pi?

Greetings, i got 2 pololulu High Power 36V9 motor drivers, and they both came brand new.

I’m trying to use it with this dc motor.

Driver purchased: HIGH-POWER MOTOR DRIVER 36V9 POLOLU - DC-motor driver | 40kHz; PWM; 9A; Uin mot: 5.5÷50V; Uin log: 5.5V; POLOLU-756 | TME - Electronic components

I installed everything according to the documentation online,

But both of the outputs OUTA and OUTB gives low, upon running the code below, giving - 0.30 on voltmeter… :confused:

I set the RESET pin to high, and just did the basic installation, (shown in sample code(

My power supply is a AC wall plug (12.5dc , 1.5AMP).

Here is my code: import RPi.GPIO as GPIOfrom time import sleepmotor=12direction=23reset -
Here is my setup (Orange cable is grey on raspberry): Imgur: The magic of the Internet

Would appreciate any help i could get, as these costs 50$ a pop, and its not fun when it dosent work :confused:
Best regards Daniel.


As described in our product page description (which is the source of the content in PDF you linked to), the logic connections on the 36v9 are designed to interface with 5V systems (5.5 V max). The minimum high input signal threshold is 3.5 V, so we do not recommend connecting it directly to 3.3 V controllers, like a Raspberry Pi. If you want to use this driver with a Raspberry Pi, you might consider using something like our logic level shifter.

In the meantime, if you just want to confirm that your driver is working, you could disconnect all your current logic connections and just connect the driver’s 5V output to PWM and DIR to GND. Then you can power your driver and check the voltage across the outputs with a multimeter.

By the way, when you initially test the board with a controller again, I recommend you just leave the driver’s RESET pin disconnected. The board pulls that pin up to V+ to enable the driver by default, so you should not need it for preliminary testing.

Also, in case you do not know about them already, we have a few G2 High-Power Motor Drivers that were specifically designed to interface with a Raspberry Pi. We do not have any models with the same voltage range as the 36v9, but if you do not need that full range, I would expect these to be easier to use:

- Patrick

Thanks for the quick reply Patrick!

I tried to do a test on the driver with all the logic pins removed from raspberry , and just have it connected to GND → DIR , and PWM to 5V(OUT) on the driver, then added supply,
Output still -0.30 on both OUT’s.
However, 1 thing i noticed is that the 5v pin is giving -0.30 V as well , shouldn’t it give ~5?

This is the image (P.S: Far right V+ pin is not soldered on)

Oh my god, i am so dumb, my power chord polarity was wrong.

However, even with setting it the correct way, the v5 output only gives 2V, and its setting the ff1 and ff2 pins to 2v aswell (I assume its high?) meaning that there is under voltage from V5 Output? :slight_smile:
Regrds :slight_smile:

The 36v9 does not have reverse power protection, so that might have damaged your driver. Can you disconnect everything except VIN and GND and try measuring the 5V output again?

Also, from what I can see in your picture, your solder joints look pretty bad, so you might check out the Adafruit Guide to Excellent Soldering.

- Patrick