I’ve got a Uno R4 Wifi and a Grove I2C Motor Controller.
No matter what I do, I can’t seem to get the motor to output anything else than roughly 11-12V DC. I can successfully reverse the polarity of the motor (ie. pass a negative speed value) and see the LED on the board indicate that change, but the output voltage remains at a constant 11-12V regardless.
My understanding was that the voltage output would drop as I passed a lower integer value to the speed parameter on the Motor.speed() call. I’ve also tried calling Motor.stop(MOTOR1) and still see a voltage across the output.
A friend suggested that there might be a compatibility problem between the Motor Controller and the Uno R4 (as opposed to an earlier Uno eg R3) but it was a bit of a stab in the dark and I don’t have any earlier hardware to test with.
I’m using the library recommended and the source code in the guide on the Seeed wiki linked to above.
