Qwiic Motor Driver not completely turning off power to motor

Robotics
1

Hi,

Please can I get some help with using the Qwiic Motor Driver.

I’m struggling with getting the Motor Driver to complete stop supplying power to the motor.

I have connected the driver with a 6V power source to a brushless pump motor.

The motor starts with the call setDrive( 0, 0, 255), and the full 6V is supplied to the motor.

The motor stops with the call setDrive( 0, 0, 0) – however, power of 0.8V is still supplied to the motor and there is an audible electronic noise from the motor.

If I remove the motor (i.e. no load) then the power drops to 0.02V after the call setDrive( 0, 0, 0).

I have tried different drivers and different motors with the same outcome.

I realise I am not using the full functionality of the driver and just want to use it as a relay to power the pump on/off.

What do I need to do to completely turn off the power or is it not possible with this driver?

This issue may be related to the recent post - QWIIC MOTOR DRIVER IDLE CURRENT DRAW

viewtopic.php?f=107&t=55887

Motor Spec (D250BLZ) - https://micropumps.co.uk/DATA/pdf/DS06% … 0small.pdf

Relevant Arduino Code

//Initialise Motor Driver 1-2

scMotorDriver12.settings.commInterface = I2C_MODE;

scMotorDriver12.settings.I2CAddress = 0x5D;

while ( scMotorDriver12.begin() != 0xA9 ) //Wait until a valid ID word is returned

{

Serial.println( “ID mismatch, trying again” );

delay(500);

}

Serial.println( “ID matches 0xA9” );

// Check to make sure the driver is done looking for slaves before beginning

Serial.print(“Waiting for enumeration…”);

while ( scMotorDriver12.ready() == false );

//Enables the output driver hardware

while ( scMotorDriver12.busy() );

scMotorDriver12.enable();

Serial.println(“Done.”);

Serial.println();

//Stop motor 1

scMotorDriver12.setDrive( 0, 0, 0);

//Set motor 1 to full

scMotorDriver12.setDrive( 0, 0, 255);

2

I was going through the datasheet’s function list and it looks like this might help? Try adding it in and see if the behavior changes

void disable( void ); //Call to remove drive from the H-bridges. All outputs will go low

And report back?

3

Thanks TS-Russell, that does the trick.

Using disable does completely stop the power.

It does mean that in my circumstance I can only power one motor with this driver (probably a wrong use case and I should be using a relay).

It might be worth adding a note on this to the driver’s details page as if a user is unaware it could overheat / damage components and/or use unnecessary power.

There are a couple of forum posts that are linked to this, so I think a common issue.

Thanks for your help.