Add a movement sensor

Add a movement sensor to your machine’s configuration so you can track position, velocity, and orientation from the Viam app and from code.

Concepts

Unlike a generic sensor (which returns arbitrary readings), a movement sensor has a structured API with specific methods for spatial data:

• GetPosition: latitude, longitude, altitude.
• GetLinearVelocity: speed in X, Y, Z.
• GetAngularVelocity: rotation rate around each axis.
• GetCompassHeading: heading in degrees.
• GetOrientation: orientation as Euler angles or quaternion.

Not every movement sensor supports every method. A GPS provides position and compass heading but not angular velocity. An IMU provides orientation and angular velocity but not GPS position. Use GetProperties to check which methods a particular sensor supports.

Built-in models

Hardware-specific models (GPS modules, IMUs, RTK receivers) are available as modules in the Viam registry.

Steps

Option A: Wheeled odometry (no extra hardware)

If you have a wheeled base with encoders on the motors, you can get position and velocity estimates without any additional sensors.

1. Prerequisites

• A wheeled base with motors that have encoders configured.

2. Add the movement sensor

1. Click the + button.
2. Select Configuration block.
3. Search for wheeled-odometry. This is the built-in model that computes position from wheel encoder data.
4. Name it (for example, odometry) and click Create.

3. Configure attributes

{
  "base": "my-base",
  "left_motors": ["left-motor"],
  "right_motors": ["right-motor"]
}

Option B: Hardware sensor (GPS, IMU)

1. Add the component

1. Click the + button.
2. Select Configuration block.
3. Search for the model that matches your sensor hardware. Search by sensor name or chip (for example, NMEA GPS, BNO055, MPU6050).
4. Name it and click Create.
5. Configure attributes per the model’s documentation (typically I2C address or serial port).

Option C: Merged sensor

Combine data from multiple movement sensors into one.

{
  "position": "gps-sensor",
  "orientation": "imu-sensor",
  "compass_heading": "gps-sensor",
  "angular_velocity": "imu-sensor",
  "linear_velocity": "odometry"
}

Each field names the movement sensor to use for that type of data. This lets you build a complete spatial picture from multiple hardware sources.

Save and test

Click Save, then expand the Test section.

• The test panel shows all available data: position, velocity, orientation, and heading.
• Methods the sensor doesn’t support will show as unavailable.

Try it

Read position and velocity data from the movement sensor.

To get the credentials for the code below, go to your machine’s page in the Viam app, click the CONNECT tab, and select API keys. Copy the API key and API key ID. Copy the machine address from the same tab. When you run the code below, you’ll see which methods your sensor supports and the current readings for each.

pip install viam-sdk

import asyncio
from viam.robot.client import RobotClient
from viam.components.movement_sensor import MovementSensor


async def main():
    opts = RobotClient.Options.with_api_key(
        api_key="YOUR-API-KEY",
        api_key_id="YOUR-API-KEY-ID"
    )
    robot = await RobotClient.at_address("YOUR-MACHINE-ADDRESS", opts)

    sensor = MovementSensor.from_robot(robot, "odometry")

    # Check which methods this sensor supports
    properties = await sensor.get_properties()
    print(f"Supports position: {properties.position_supported}")
    print(f"Supports linear velocity: {properties.linear_velocity_supported}")
    print(f"Supports angular velocity: {properties.angular_velocity_supported}")
    print(f"Supports compass heading: {properties.compass_heading_supported}")

    if properties.position_supported:
        position = await sensor.get_position()
        print(f"Position: {position}")

    if properties.linear_velocity_supported:
        velocity = await sensor.get_linear_velocity()
        print(f"Linear velocity: {velocity}")

    await robot.close()

if __name__ == "__main__":
    asyncio.run(main())

python movement_sensor_test.py

mkdir movement-sensor-test && cd movement-sensor-test
go mod init movement-sensor-test
go get go.viam.com/rdk

package main

import (
    "context"
    "fmt"

    "go.viam.com/rdk/components/movementsensor"
    "go.viam.com/rdk/logging"
    "go.viam.com/rdk/robot/client"
    "go.viam.com/rdk/utils"
)

func main() {
    ctx := context.Background()
    logger := logging.NewLogger("movement-sensor-test")

    robot, err := client.New(ctx, "YOUR-MACHINE-ADDRESS", logger,
        client.WithCredentials(utils.Credentials{
            Type:    utils.CredentialsTypeAPIKey,
            Payload: "YOUR-API-KEY",
        }),
        client.WithAPIKeyID("YOUR-API-KEY-ID"),
    )
    if err != nil {
        logger.Fatal(err)
    }
    defer robot.Close(ctx)

    sensor, err := movementsensor.FromProvider(robot, "odometry")
    if err != nil {
        logger.Fatal(err)
    }

    // Check which methods this sensor supports
    properties, err := sensor.Properties(ctx, nil)
    if err != nil {
        logger.Fatal(err)
    }
    fmt.Printf("Supports position: %v\n", properties.PositionSupported)
    fmt.Printf("Supports linear velocity: %v\n", properties.LinearVelocitySupported)
    fmt.Printf("Supports angular velocity: %v\n", properties.AngularVelocitySupported)
    fmt.Printf("Supports compass heading: %v\n", properties.CompassHeadingSupported)

    if properties.PositionSupported {
        pos, alt, err := sensor.Position(ctx, nil)
        if err != nil {
            logger.Fatal(err)
        }
        fmt.Printf("Position: %v, altitude: %.2f\n", pos, alt)
    }

    if properties.LinearVelocitySupported {
        vel, err := sensor.LinearVelocity(ctx, nil)
        if err != nil {
            logger.Fatal(err)
        }
        fmt.Printf("Linear velocity: %v\n", vel)
    }
}

go run main.go

Troubleshooting

What’s next

• Movement sensor API reference: full method documentation.
• Add a Base: the movement sensor typically pairs with a mobile base.
• Capture and Sync Data: capture position and motion data over time.