Configure a Rover like Yahboom or SCUTTLE

This tutorial will guide you through configuring a rover.

If you are using a SCUTTLE, a Yahboom rover, or a different rover, this tutorial covers instructions for your rover model.

Requirements

• A running an instance of viam-server. See our Installation Guide for instructions.
• A rover like the SCUTTLE robot or the Yahboom 4WD Smart Robot

Make sure your rover is assembled before starting this tutorial.

Start configuring your robot

Add a new machine in the Viam app. On the machine’s page, follow the setup instructions to install viam-server on the computer you’re using for your project. Wait until your machine has successfully connected to the Viam app.

Once connected, navigate to the machine’s CONFIGURE tab.

The configuration for each rover is different depending on which components your rover is composed of. In the following, you can see two popular examples with components that are present on most rovers:

Configure the board

The first component you will add is the board which represents the Raspberry Pi to which the other components are wired.

Click the + icon next to your machine part in the left-hand menu and select Component. Select the board type, then select the viam:raspberry-pi:rpi model. Enter local as the name and click Create. You can use a different name but will then need to adjust the name in the following steps to the name you choose.

You don’t need to add any attributes for your board.

Configuring the motors and encoders

Configure the encoders

Configure the left and right encoders as follows:

{
    "name": "lenc",
    "model": "AMS-AS5048",
    "type": "encoder",
    "namespace": "rdk",
    "attributes": {
      "connection_type": "i2c",
      "i2c_attributes": {
        "i2c_bus": "1",
        "i2c_addr": 64
      }
    }
},
{
    "name": "renc",
    "model": "AMS-AS5048",
    "type": "encoder",
    "namespace": "rdk",
    "attributes": {
      "connection_type": "i2c",
      "i2c_attributes": {
        "i2c_bus": "1",
        "i2c_addr": 65
      }
    }
}

Configure the motors

{
  "name": "right",
  "model": "gpio",
  "type": "motor",
  "namespace": "rdk",
  "attributes": {
    "pins": {
      "a": "16",
      "b": "15",
      "pwm": "",
      "dir": ""
    },
    "board": "local",
    "dir_flip": false,
    "ticks_per_rotation": 2
  },
  "depends_on": [ "local" ]
},
{
  "name": "left",
  "model": "gpio",
  "type": "motor",
  "namespace": "rdk",
  "attributes": {
    "pins": {
      "a": "12",
      "b": "11",
      "pwm": ""
    },
    "board": "local",
    "dir_flip": false,
    "ticks_per_rotation": 2
  },
  "depends_on": [ "local" ]
}

Test the motor configuration

Now that you have configured your motors, you can actuate them. Make sure your machine is turned on. Navigate to the Control tab.

You’ll see a panel for each configured component.

Click on the panel for the right motor.

Try changing the motor’s power level and click Run.

If your wheel turns in reverse when it should turn forward, add the dir_flip attribute to the motor’s configuration, by clicking Show more and setting the attribute to “true.”

There, you should see a panel for the right motor: you can use this panel to set the motor’s power level.

(Optional) Configure the camera

Optionally, add a camera to your rover.

• Config Builder
• JSON

Click the + icon next to your machine part in the left-hand menu and select Component. Select the camera type, then select the webcam model. Enter a name or use the suggested name for your camera and click Create.

If you click on the Video Path field while your robot is live, a dropdown autopopulates with identified camera paths.

{
  "name": "Webcam",
  "model": "webcam",
  "type": "camera",
  "namespace": "rdk",
  "attributes": {
    "video_path": "<PATH_TO_YOUR_WEBCAM>"
  }
}

If your rover has its camera mounted on a pair of servos, like the Yahboom rover, you can use these to control the pan and tilt of the camera.

Click the + icon next to your machine part in the left-hand menu and select Component. Select the servo type, then select the viam:raspberry-pi:pi-servo model. Enter pan as the name and click Create.

Set Depends On to local, and pin to the pin the servo is wired to (23 for the Yahboom rover).

Finally, add the tilt servo as well. Click the + icon next to your machine part in the left-hand menu and select Component. Select the servo type, then select the viam:raspberry-pi:pi-servo model. Enter tilt as the name and click Create.

Set Depends On to local, and pin to the pin the servo is wired to (21 for the Yahboom rover).

Test the camera stream

Once your camera is configured and connected, expand the TEST panel on the CONFIGURE or CONTROL tabs. If everything is configured correctly, you will see the live feed from your camera.

Configure the base

Next, configure the base component, which describes the geometry of your chassis and wheels so that the software can calculate how to steer the rover in a coordinated way. Configuring a base component also provides you with a nice UI for moving the rover around.

• Config Builder
• JSON

Click the + icon next to your machine part in the left-hand menu and select Component. Select the base type, then select the wheeled model. Enter a name or use the suggested name for your base and click Create.

• SCUTTLE
• Yahboom
• Other

1. Select the motors attached to the base in the fields as your right and left motors.
2. Enter 250 for wheel_circumference_mm.
3. Enter 400 for width_mm (measured between the midpoints of the wheels).

1. Select the motors attached to the base in the fields as your right and left motors.
2. Enter 220 for wheel_circumference_mm.
3. Enter 150 for width_mm (measured between the midpoints of the wheels).

1. Select the motors attached to the base in the fields as your right and left motors.
2. Measure the wheel circumference in mm and enter it in the field for wheel_circumference_mm.
3. Measure the width in mm between the midpoints of the wheels and enter it in the field for width_mm (measured between the midpoints of the wheels).

{
  "components": [
    {
      "attributes": {
        "board": "local",
        "pins": {
          "pwm": "",
          "a": "16",
          "b": "15"
        }
      },
      "model": "gpio",
      "name": "right",
      "type": "motor"
    },
    {
      "attributes": {
        "board": "local",
        "pins": {
          "pwm": "",
          "a": "12",
          "b": "11"
        }
      },
      "model": "gpio",
      "name": "left",
      "type": "motor"
    },
    {
      "attributes": {
        "left": ["left"],
        "right": ["right"],
        "wheel_circumference_mm": 250,
        "width_mm": 400
      },
      "model": "wheeled",
      "name": "your-wheeled-base",
      "type": "base"
    }
  ]
}

Save the config by clicking Save at the top right of the page.

Test the base

After you configure the base, open the base’s TEST panel on the CONFIGURE or CONTROL tabs to view the controls to enable keyboard or discrete control over your machine’s movement.

In the Quick move section, you can toggle the keyboard control to active. With the Keyboard toggle active, use W and S to go forward and back, and A and D to arc and spin.

Try driving your base around using the WASD keyboard controls.

You can also move straight, spin, set power or set velocity from the base panel.

If you do not see the base card in the TEST panel, check the LOGS tab for possible setup or configuration errors.

Next steps

Now that you have fully configured your SCUTTLE robot, you can drive it around and view its camera stream.

To take things to the next level, check out one of the following tutorials: