# wheeled-odometry

Configure a `wheeled-odometry` movement sensor to implement _wheeled odometry_ on your machine.

_Wheeled odometry_ is the estimation of the rate of change of position, orientation, linear velocity, and angular velocity using the dimensions of a base, calculated by measuring the movement of the motors through encoders. Because of this method of estimation, you don’t have to have a specific piece of movement sensor hardware to implement `wheeled-odometry` on your machine. This model uses [encoders](https://docs.viam.com/reference/components/encoder/) from [position reporting motors](https://docs.viam.com/reference/components/motor/) to get an odometry estimate of a wheeled base as it moves.

With a configured `wheeled-odometry` movement sensor, your machine calculates an estimation of the position, orientation, linear velocity, and angular velocity of the wheeled base each time `time_interval_msec` elapses during a [session](https://docs.viam.com/reference/apis/sessions/). You can access these readings through the [movement sensor API](https://docs.viam.com/reference/apis/components/movement-sensor/#api). For the best accuracy with odometry calculations, it is recommended you configure a time interval of less than `1000` milliseconds.

## Set-up requirements

To prepare your machine, attach [encoders](https://docs.viam.com/reference/components/encoder/) to each of the position-reporting motors on your base to measure their rotation.

- Select and configure motors that can report their own position, like [`gpio` motors](https://docs.viam.com/reference/components/motor/gpio/) with [encoders](https://docs.viam.com/reference/components/encoder/), or the [`odrive` module](https://github.com/viam-modules/odrive). You can access this property of a configured motor through the [motor API’s `GetProperties()`](https://docs.viam.com/reference/apis/components/motor/#getproperties).
- Configure your rover as a [wheeled base component](https://docs.viam.com/reference/components/base/wheeled/). Make sure to configure the base width and circumference, as these measurements as a property of the base are vital for accurate odometry estimations by your movement sensor. This movement sensor accesses these values through the base’s `GetProperties()` API method.
- Then, proceed to [configure](https://docs.viam.com/reference/components/movement-sensor/wheeled-odometry/#configuration) a `wheeled-odometry` movement sensor with the name of each of the motor components.

## Configuration

- [JSON Template](https://docs.viam.com/reference/components/movement-sensor/wheeled-odometry/#tabset-referencecomponentsmovement-sensorwheeled-odometry-1-0)
- [JSON Example](https://docs.viam.com/reference/components/movement-sensor/wheeled-odometry/#tabset-referencecomponentsmovement-sensorwheeled-odometry-1-1)

```json

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```json

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## Attributes

The following attributes are available for `wheeled-odometry` movement sensors:

| Name | Type | Required? | Description |
| --- | --- | --- | --- |
| `base` | string | **Required** | The `name` of the [base](https://docs.viam.com/reference/components/base/) to which the encoders making up this movement sensor are wired. |
| `left_motors` | object | **Required** | A list containing the name of each of the bases’ left [position-reporting motors](https://docs.viam.com/reference/components/motor/gpio/). |
| `right_motors` | object | **Required** | A list containing the name of each of the bases’ right [position-reporting motors](https://docs.viam.com/reference/components/motor/gpio/). |
| `time_interval_msec` | float | Optional | The time in milliseconds between each wheeled odometry calculation.<br>Default: `500.0` |