Configure a GPIO-Controlled Servo

Configure a gpio servo to integrate a hobby servo controlled by general-purpose input/output (GPIO) pins on a non-viam:raspberry-pi:rpi model board into your machine. Physically connect your servo to your board and power both on. Then, configure the servo:

• Config Builder
• JSON Template
• JSON Example

Navigate to the CONFIGURE tab of your machine’s page in the Viam app. Click the + icon next to your machine part in the left-hand menu and select Component. Select the servo type, then select the gpio model. Enter a name or use the suggested name for your servo and click Create.

Fill in the attributes as applicable to your servo, according to the table below.

{
  "components": [
    {
      "name": "<your-servo-name>",
      "model": "gpio",
      "type": "servo",
      "namespace": "rdk",
      "attributes": {
        "pin": "<your-pin-number>",
        "board": "<your-board-name>",
        "min_angle_deg": <float>,
        "max_angle_deg": <float>,
        "starting_position_deg": <float>,
        "frequency_hz": <int>,
        "pwm_resolution": <int>,
        "min_width_us": <int>,
        "max_width_us": <int>
      }
    }
  }

{
  "components": [
    {
      "name": "local",
      "model": "jetson",
      "type": "board",
      "namespace": "rdk"
    },
    {
      "name": "my_servo",
      "model": "gpio",
      "type": "servo",
      "namespace": "rdk",
      "attributes": {
        "pin": "16",
        "board": "local"
      }
    }
  ]
}

The following attributes are available for gpio servos:

Test the servo

After you establish the connection to your servo motor, open the servo’s TEST panel on the CONFIGURE or CONTROL tabs. Use the buttons to move the servo motor to the desired angle.

Troubleshooting

If your servo is not working as expected, follow these steps:

1. Check your machine logs on the LOGS tab to check for errors.
2. Review this servo model’s documentation to ensure you have configured all required attributes.
3. Check that all wires are securely attached to the correct pins on the board.
4. Click on the TEST panel on the CONFIGURE or CONTROL tab and test if you can use the servo there.

If none of these steps work, reach out to us on the Community Discord and we will be happy to help.

Next steps

For general configuration and development info, see: