| .. _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 sample requires a servomotor whose signal pin is connected to a pin driven |
| by PWM. The servo must be defined in Devicetree using the ``pwm-servo`` |
| compatible (part of the sample) and setting its node label to ``servo``. You |
| will need to do something like this: |
| |
| .. code-block:: devicetree |
| |
| / { |
| servo: servo { |
| compatible = "pwm-servo"; |
| pwms = <&pwm0 1 PWM_MSEC(20) PWM_POLARITY_NORMAL>; |
| min-pulse = <PWM_USEC(700)>; |
| max-pulse = <PWM_USEC(2500)>; |
| }; |
| }; |
| |
| Note that a commonly used period value is 20 ms. See |
| :zephyr_file:`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 P19 on the edge connector. |
| |
| Building and Running |
| ******************** |
| |
| The sample has a devicetree overlay for the :ref:`bbc_microbit`. |
| |
| 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: |
