Sensor Component

A sensor is a device that can measure information about the outside world. Add a sensor component to your machine to send the information the sensor measures to the computer controlling the machine.

Most machines with a sensor need at least the following hardware:

  • A board
  • Depending on your sensor’s output type (analog or digital), an analog-to-digital converter (ADC) may be necessary to allow the sensor to communicate with the board

Supported models

To use your motor component, check whether one of the following models supports it.

For configuration information, click on the model name:

Model
Description
ModelDescription
ultrasonicHC-SR04 ultrasonic sensors

Control your sensor with Viam’s client SDK libraries

To get started using Viam’s SDKs to connect to and control your machine, go to your machine’s page on the Viam app, navigate to the CONNECT tab’s Code sample page, select your preferred programming language, and copy the sample code generated.

When executed, this sample code will create a connection to your machine as a client. Then control your machine programmatically by adding API method calls as shown in the following examples.

These examples assume you have a sensor called "my_sensor" configured as a component of your machine. If your sensor has a different name, change the name in the code.

Be sure to import the sensor package for the SDK you are using:

from viam.components.sensor import Sensor
import (
  "go.viam.com/rdk/components/sensor"
)

API

The sensor component supports the following methods:

Method NameDescriptionmicro-RDK Support
GetReadingsGet the measurements or readings that this sensor provides.

GetGeometriesGet all the geometries associated with the sensor in its current configuration, in the frame of the sensor.

ReconfigureReconfigure this resource.

DoCommandExecute model-specific commands that are not otherwise defined by the component API.

FromRobotGet the resource from the provided robot with the given name.

GetResourceNameGet the ResourceName for this sensor with the given name.

CloseSafely shut down the resource and prevent further use.

GetReadings

Get the measurements or readings that this sensor provides. Supported by the micro-RDK.

Parameters:

  • extra (Mapping[str, Any]) (optional): Extra options to pass to the underlying RPC call.
  • timeout (float) (optional): An option to set how long to wait (in seconds) before calling a time-out and closing the underlying RPC call.

Returns:

  • (Mapping[str, viam.utils.SensorReading]): The measurements. Can be of any type.

Example:

my_sensor = Sensor.from_robot(robot=robot, name='my_sensor')

# Get the readings provided by the sensor.
readings = await my_sensor.get_readings()

For more information, see the Python SDK Docs.

Parameters:

  • ctx (Context): A Context carries a deadline, a cancellation signal, and other values across API boundaries.
  • extra (map[string]interface{}): Extra options to pass to the underlying RPC call.

Returns:

  • (map[string]interface{}): A map containing the measurements from the sensor. Contents depend on sensor model and can be of any type.
  • (error): An error, if one occurred.

Example:

// Get the readings provided by the sensor.
readings, err := mySensor.Readings(context.Background(), nil)

For more information, see the Go SDK Docs.

Parameters:

Returns:

Example:

var readings = await mySensor.readings();

For more information, see the Flutter SDK Docs.

GetGeometries

Get all the geometries associated with the sensor in its current configuration, in the frame of the sensor. The motion and navigation services use the relative position of inherent geometries to configured geometries representing obstacles for collision detection and obstacle avoidance while motion planning.

Parameters:

  • extra (Mapping[str, Any]) (optional): Extra options to pass to the underlying RPC call.
  • timeout (float) (optional): An option to set how long to wait (in seconds) before calling a time-out and closing the underlying RPC call.

Returns:

Example:

geometries = await component.get_geometries()

if geometries:
    # Get the center of the first geometry
    print(f"Pose of the first geometry's centerpoint: {geometries[0].center}")

For more information, see the Python SDK Docs.

Reconfigure

Reconfigure this resource. Reconfigure must reconfigure the resource atomically and in place.

Parameters:

  • ctx (Context): A Context carries a deadline, a cancellation signal, and other values across API boundaries.
  • deps (Dependencies): The resource dependencies.
  • conf (Config): The resource configuration.

Returns:

  • (error): An error, if one occurred.

For more information, see the Go SDK Docs.

DoCommand

Execute model-specific commands that are not otherwise defined by the component API. For built-in models, model-specific commands are covered with each model’s documentation. If you are implementing your own sensor and add features that have no built-in API method, you can access them with DoCommand. Supported by the micro-RDK.

Parameters:

  • command (Mapping[str, ValueTypes]) (required): The command to execute.
  • timeout (float) (optional): An option to set how long to wait (in seconds) before calling a time-out and closing the underlying RPC call.

Returns:

  • (Mapping[str, viam.utils.ValueTypes]): Result of the executed command.

Raises:

  • (NotImplementedError): Raised if the Resource does not support arbitrary commands.

Example:

command = {"cmd": "test", "data1": 500}
result = component.do(command)

For more information, see the Python SDK Docs.

Parameters:

Returns:

Example:

// This example shows using DoCommand with an arm component.
myArm, err := arm.FromRobot(machine, "my_arm")

command := map[string]interface{}{"cmd": "test", "data1": 500}
result, err := myArm.DoCommand(context.Background(), command)

For more information, see the Go SDK Docs.

Parameters:

Returns:

Example:

// Example using doCommand with an arm component
const command = {'cmd': 'test', 'data1': 500};
var result = myArm.doCommand(command);

For more information, see the Flutter SDK Docs.

FromRobot

Get the resource from the provided robot with the given name.

Parameters:

Returns:

For more information, see the Flutter SDK Docs.

GetResourceName

Get the ResourceName for this sensor with the given name.

Parameters:

  • name (str) (required): The name of the Resource.

Returns:

Example:

# Can be used with any resource, using an arm as an example
my_arm_name = my_arm.get_resource_name("my_arm")

For more information, see the Python SDK Docs.

Parameters:

Returns:

For more information, see the Flutter SDK Docs.

Close

Safely shut down the resource and prevent further use.

Parameters:

  • None.

Returns:

  • None.

Example:

await component.close()

For more information, see the Python SDK Docs.

Parameters:

  • ctx (Context): A Context carries a deadline, a cancellation signal, and other values across API boundaries.

Returns:

  • (error): An error, if one occurred.

Example:

// This example shows using Close with an arm component.
myArm, err := arm.FromRobot(machine, "my_arm")

err = myArm.Close(ctx)

For more information, see the Go SDK Docs.

Troubleshooting

You can find additional assistance in the Troubleshooting section.

You can also ask questions in the Community Discord and we will be happy to help.

Next steps