.. _servo-motor-sample:
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
************
The servomotor must be connected via PWM. The PWM device must be configured
using the ``pwm-servo`` :ref:`devicetree <dt-guide>` alias. Usually you will
need to set this up via a :ref:`devicetree overlay <set-devicetree-overlays>`
like so:
.. code-block:: DTS
/ {
aliases {
pwm-servo = &foo;
};
};
Where ``foo`` is the node label of a PWM device in your system.
You will see this error if you try to build this sample for an unsupported
board:
.. code-block:: none
Unsupported board: pwm-servo devicetree alias is not defined
The sample uses PWM channel 0.
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 pad 0 on the edge connector.
Building and Running
********************
The sample has a devicetree overlay for the :ref:`bbc_microbit` which uses
``pwm0``.
This sample can be built for multiple boards, in this example we will build it
for the bbc_microbit board:
.. zephyr-app-commands::
:zephyr-app: samples/basic/servo_motor
:board: bbc_microbit
:goals: build flash
:compact:
e959386bd2