Configure a Fake Input Controller for Testing

Configuring a fake input controller allows you to test an input controller communicating with your machine, without any physical hardware.

This controller can have Controls defined in attributes, as seen in the “JSON Template” tab below. However, these Controls only ever return a single PositionChangeAbs event on the X axis, with the Event.value stuck at 0.7.

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 input_controller type, then select the fake model. Enter a name or use the suggested name for your input controller and click Create.

An example configuration for a fake input controller component in the Viam App config builder.

Edit the attributes as applicable.

  "components": [
      "name": "<your-fake-input-controller>",
      "model": "fake",
      "type": "input_controller",
      "namespace": "rdk",
      "attributes": {
        "controls": [
        "event_value": <float>,
        "callback_delay_sec": <float>

The following attributes are available for fake input controllers:

callback_delay_secfloatRequiredThe number of seconds between callbacks getting triggered. Random between 1 and 2 if not specified. 0 is not valid and will be overwritten by a random delay.
event_valuefloatOptionalSet the value of events returned. Random between -1 and 1 if not specified.
controlsarrayOptionalSet the Controls that are present on the controller.

Test the input controller

After you configure your input controller, navigate to the Control tab and select the dropdown panel dedicated to the input controller. View the current value of each input on your controller.

The input controller component in the control tab of the Viam app.


You can find additional assistance in the Troubleshooting section.

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