Drive a Rover (like SCUTTLE or Yahboom) Using a Gamepad

By the end of this tutorial, you’ll be able to drive your rover around like an RC car.

Requirements

You will need the following hardware to complete this tutorial:

• A wheeled rover, configured with a base component on the Viam app. This tutorial uses a SCUTTLE rover as an example but you can complete this tutorial using a Yahboom 4WD Smart Robot or an entirely different rover.
  • For a tutorial on configuring your rover, see Configure a Rover.
• EasySMX ESM-9101 Wireless Controller or a similar gamepad and dongle. This is the controller that comes with the SCUTTLE rover. You can also use an 8BitDo controller with additional setup.

Set up the hardware

If your gamepad has a dongle, plug the gamepad Bluetooth dongle into a USB port on the rover’s board. Then turn on power to the rover.

Add the controller to the rover’s config

Go to your rover’s CONFIGURE tab on the Viam app.

{
  "name": "my-gamepad",
  "model": "gamepad",
  "type": "input_controller",
  "namespace": "rdk",
  "attributes": { "auto_reconnect": true },
  "depends_on": []
}

The controller config adds the gamepad controller to your machine. However, it is not functional yet. To link the controller input to the base functionality, you need to add the base remote control service.

Add the base remote control service

Services are software packages that provide robots with higher level functionality. To link the controller’s input to the base functionality, you need to configure the base remote control service:

{
  "base": "<your-base-name>",
  "input_controller": "my-gamepad"
}

  "services": [
    {
      "name": "gamepad_service",
      "type": "base_remote_control",
      "attributes": {
        "input_controller": "my-gamepad",
        "base": "<your-base-name>"
      }
    }
  ]

Click Save, then go to the CONTROL tab.

You should see the panel for the gamepad and its connection indicator:

Try moving the left joystick or pressing the D-pad to move the rover using the gamepad.

The ESM-9101 controller has different modes that allow you to use either the joystick or the D-pad. If you are in the mode that allows you to use the joystick (#7), it will change the X and Y values on the Control tab gamepad panel:

"X
0.0000
Y
0.0000"

If you are in the mode that allows you to use the D-pad (#8), it will change the Hat0X and Hat0Y values:

"Hat0X
0.0000
Hat0Y
0.0000"

Testing these attributes tells you which mode you are in.

EasySMX ESM-9101 wireless controller information

Here is a diagram of the gamepad.

To change the movement/direction control on the gamepad between the D-pad and the joystick, press and hold the Home button (#11) until it displays the lighted segment combination for the gamepad configuration you need. Each red color arrangement allows you to control the gamepad in the Viam app:

LED 1 and 3: Use the D-Pad	LED 3 and 4: Use the D-Pad
LED 1 and 2: Use the D-Pad	LED 1 and 4: Use the Joystick

Next steps

You can now drive your rover with a wireless controller. If you’d like to do more with your rover, check out one of these tutorials:

Drive with the SDK

Use a Viam SDK to program a rover to move in a square.

Detect Color

Use the vision service in the Viam app to detect a color.

Navigate with a Rover

Introduction to using a rover base with the navigation service.