6.3. Motors

The Zumo 2040 robot is available with three different motor options:

You can also assemble the Zumo kit with different motor and gear ratio combinations to make your own custom Zumo 2040 robot. Section 1.2 discusses some things to consider when choosing motors.

Two on-board motor drivers power the Zumo 2040’s two Micro Metal Gearmotors. Four GPIO pins are used to control the drivers:

• GP10 controls the right motor direction.
• GP11 controls the left motor direction.
• GP14 controls the right motor speed with PWM (pulse width modulation) generated by the RP2040’s PWM7 A channel.
• GP15 controls the left motor speed with PWM generated by the PWM7 B channel.

The Zumo 2040 Robot Libraries and Example Code provide functions that allow you to easily control the motors, and it can optionally take care of flipping a direction signal for you if you accidentally soldered in a motor backwards or are using a gear ratio with an odd number of stages, so the output turns the opposite direction from the input.

As your batteries run out, the voltage supplied to the motor drivers (VSW) will decrease, which will make the motors slower. It is possible to account for this in your code by monitoring the battery voltage (see Section 6.8) or using the encoders and other sensors to monitor the movement of the robot.