# wheeled

A `wheeled` base supports mobile robotic bases with motors on both sides (differential steering). To configure a `wheeled` base as a component of your machine, first configure the [board](https://docs.viam.com/reference/components/board/) controlling the base and any [motors](https://docs.viam.com/reference/components/motor/) attached to the base.

If you want to test your base as you configure it, physically assemble the base, connect it to your machine’s computer, and turn it on.

- [JSON Template](https://docs.viam.com/reference/components/base/wheeled/#configure-a-wheeled-base-0)
- [JSON Example](https://docs.viam.com/reference/components/base/wheeled/#configure-a-wheeled-base-1)

```json
{
  "components": [
    {
      "name": "my-pi",
      "model": "pi",
      "api": "rdk:component:board",
      "attributes": {},
      "depends_on": []
    },
    {
      "name": "rightm",
      "model": "gpio",
      "api": "rdk:component:motor",
      "attributes": {
        "pins": {
          "dir": "16",
          "pwm": "15"
        },
        "board": "my-pi"
      },
      "depends_on": []
    },
    {
      "name": "leftm",
      "model": "gpio",
      "api": "rdk:component:motor",
      "attributes": {
        "pins": {
          "dir": "13",
          "pwm": "11"
        },
        "board": "my-pi"
      },
      "depends_on": []
    },
    {
      "name": "my-wheeled-base",
      "model": "wheeled",
      "api": "rdk:component:base",
      "attributes": {
        "width_mm": 195,
        "wheel_circumference_mm": 183,
        "left": ["leftm"],
        "right": ["rightm"]
      },
      "depends_on": []
    }
  ]
}
```

The following attributes are available for `wheeled` bases:

| Name | Type | Required? | Description |
| --- | --- | --- | --- |
| `left` | array | **Required** | Array with the `name` of any drive motors on the left side of the base. |
| `right` | array | **Required** | Array with the `name` of any drive motors on the right side of the base. |
| `wheel_circumference_mm` | int | **Required** | The outermost circumference of the drive wheels in millimeters. Used for odometry. Can be an approximation. |
| `width_mm` | int | **Required** | Width of the base in millimeters. In other words, the distance between the approximate centers of the right and left wheels. Can be an approximation. |
| `spin_slip_factor` | float | Optional | Can be used in steering calculations to correct for slippage between the wheels and the floor. If used, calibrated by the user. |

## Wire a `wheeled` base

An example wiring diagram for a base with one motor on each side:

Note that your base’s wiring will vary depending on your choice of board, motors, motor drivers, and power supply.