This is the documentation for the latest (master) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

Servomotor

Overview

This is a sample app which drives a servomotor using PWM.

The sample rotates a servomotor back and forth in the 180 degree range with a PWM control signal.

This app is targeted for servomotor ROB-09065. The corresponding PWM pulse widths for a 0 to 180 degree range are 700 to 2300 microseconds, respectively. Different servomotors may require different PWM pulse widths, and you may need to modify the source code if you are using a different servomotor.

Requirements

You will see this error if you try to build this sample for an unsupported board:

Unsupported board: pwm-servo devicetree alias is not defined

The sample requires a servomotor whose signal pin is connected to a PWM device’s channel 0. The PWM device must be configured using the pwm-servo devicetree alias. Usually you will need to set this up via a devicetree overlay like so:

/ {
     aliases {
             pwm-servo = &some_pwm_node;
     };
};

Where some_pwm_node is the node label of a PWM device in your system.

See samples/basic/servo_motor/boards/bbc_microbit.overlay for an example.

Wiring

BBC micro:bit

You will need to connect the motor’s red wire to external 5V, the black wire to ground and the white wire to the SCL pin, i.e. pin 21 on the edge connector.

Building and Running

The sample has a devicetree overlay for the BBC MicroBit.

This sample can be built for multiple boards, in this example we will build it for the bbc_microbit board:

west build -b bbc_microbit samples/basic/servo_motor
west flash