Explorer PHAT, motor one only goes forward and motor two backwards

Got an explorer PHAT connected to my PI zero and driving two of your micro motors

using the test program and one of my own to just drive the motors, motor one goes forward and motor two goes backwards.

I am using a 2A PSU for the PI zero.
Because the motors turn I am assuming my soldering is okay.

Is it possible I have damaged one of the motor chips? Lets just say I had fun and games soldering the output connector and could have put too much heat on it!

Can you think of anything I could look at to investigate further?

After I posted this I looked at the source code for explorerhat, the I2C bus is only used for the A/D and the motor driver uses GPIO pins, 19,20,21,26. So it could be my soldering on the PI connector?

I will check those pins by driving a LED.



Try reversing the power and ground wires for the motor that goes backwards!

motor changes direction, which still indicates a problem with the output chip?

The chip is working as expected. If you switch the polarity of a motor, it spins the other direction.

It’s unlikely the chip is damaged, it’s definitely one of the hardier chips on the board. Could you post the code you’re using?

The problem is with my PIZero.
I have used some 4tronix traffic light less to check the GPIO pins. I confused myself last night by reading the connector the wrong way, which does not help!

basically pins 19 and 26 are not working, these are used for M1F and M2B on the motor which I guess explains why the motors only move in one direction.

I have not used these pins before, to date I have only used (21,20,16) and (7,8,25), so I do not know whether they have ever worked or I have damaged them.

Tomorrow I will take the PI zero out of its case and check my soldering.

Before I connect the explorer hat to another PI I think I will check it out on its own, what pins does it use for power?

It could very easily be the soldering on one side or another, it doesn’t take much to make a flaky connection.

You should only need +5V power, from either of the 5v pins to run the motor driver: http://pinout.xyz/pinout/pin2_5v_power

I had forgotten that I soldered the connector on the PI zero, otherwise that would have been the first thing I checked!

I will have look over Easter and let you know.
Thanks for the response

Oops, it was my soldering of the PI zero connector that was the problem, so all ok now.

1 Like