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Servo API

The servo API allows you to give commands to your servo components for controlling the angular position of a servo precisely or getting its current status.

The servo component supports the following methods:

Method Name	Description	`viam-micro-server` Support
`Move`	Move the servo to the desired angle in degrees.
`GetPosition`	Get the current set angle of the servo in degrees.
`IsMoving`	Returns whether the servo is actively moving (or attempting to move) under its own power.
`Stop`	Stop the servo from moving.
`Reconfigure`	Reconfigure this resource.
`DoCommand`	Execute model-specific commands that are not otherwise defined by the component API.
`GetResourceName`	Get the `ResourceName` for this servo with the given name.
`Close`	Safely shut down the resource and prevent further use.

Establish a connection

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.

API key and API key ID

By default, the sample code does not include your machine API key and API key ID. We strongly recommend that you add your API key and API key ID as an environment variable and import this variable into your development environment as needed.

To show your machine’s API key and API key ID in the sample code, toggle Include API key on the CONNECT tab’s Code sample page.

Caution

Do not share your API key or machine address publicly. Sharing this information could compromise your system security by allowing unauthorized access to your machine, or to the computer running your machine.

When executed, this sample code creates a connection to your machine as a client.

The following examples assume you have a servo called "my_servo" configured as a component of your machine. If your servo has a different name, change the name in the code.

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

Python
Go

from viam.components.servo import Servo

import (
  "go.viam.com/rdk/components/servo"
)

API

Move

Move the servo to the desired angle in degrees.

Stability Notice

Support for continuous servos with the GPIO servo model is experimental. Stability is not guaranteed. Breaking changes are likely to occur, and occur often.

If you are using a continuous rotation servo, you can use the Move command, but instead of moving to a given position, the servo will start moving at a set speed.

The speed will be related to the “angle” you pass in as a linear approximation. 90 degrees represents stop, 91 to 180 represents counter-clockwise rotation from slowest to fastest, and 89 to 1 represents clockwise from slowest to fastest. It is recommended that you test your servo to determine the desired speed.

Supported by viam-micro-server.

Parameters:

angle (int) (required): The desired angle of the servo in degrees.
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:

None.

Example:

my_servo = Servo.from_robot(robot=robot, name="my_servo")

# Move the servo from its origin to the desired angle of 10 degrees.
await my_servo.move(10)

# Move the servo from its origin to the desired angle of 90 degrees.
await my_servo.move(90)

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.
angleDeg (uint32): The desired angle of the servo in degrees.
extra (map[string]interface{}): Extra options to pass to the underlying RPC call.

Returns:

(error): An error, if one occurred.

Example:

// Move the servo from its origin to the desired angle of 30 degrees.
myServoComponent.Move(context.Background(), 30, nil)

For more information, see the Go SDK Docs.

Parameters:

angle int (required)
extra Map<String, dynamic>? (optional)

Returns:

Future<void>

Example:

// Move the servo from its origin to the desired angle of 30 degrees.
await myServo.move(30);

For more information, see the Flutter SDK Docs.

GetPosition

Get the current set angle of the servo in degrees. Supported by viam-micro-server.

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:

(int): The current angle of the servo in degrees.

Example:

my_servo = Servo.from_robot(robot=robot, name="my_servo")

# Move the servo from its origin to the desired angle of 10 degrees.
await my_servo.move(10)

# Get the current set angle of the servo.
pos1 = await my_servo.get_position()

# Move the servo from its origin to the desired angle of 20 degrees.
await my_servo.move(20)

# Get the current set angle of the servo.
pos2 = await my_servo.get_position()

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:

(uint32): The current set angle of the servo in degrees.
(error): An error, if one occurred.

Example:

// Get the current set angle of the servo.
pos1, err := myServoComponent.Position(context.Background(), nil)

// Move the servo from its origin to the desired angle of 20 degrees.
myServoComponent.Move(context.Background(), 20, nil)

// Get the current set angle of the servo.
pos2, err := myServoComponent.Position(context.Background(), nil)

logger.Info("Position 1: ", pos1)
logger.Info("Position 2: ", pos2)

For more information, see the Go SDK Docs.

Parameters:

extra Map<String, dynamic>? (optional)

Returns:

Future<int>

Example:

var angle = await myServo.position();

For more information, see the Flutter SDK Docs.

IsMoving

Returns whether the servo is actively moving (or attempting to move) under its own power.

Parameters:

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:

(bool): Whether the servo is moving.

Example:

my_servo = Servo.from_robot(robot=robot, name="my_servo")

print(await my_servo.is_moving())

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:

(bool): Whether this resource is moving (true) or not (false).
(error): An error, if one occurred.

Example:

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

// Stop all motion of the arm. It is assumed that the arm stops immediately.
myArm.Stop(context.Background(), nil)

// Log if the arm is currently moving.
is_moving, err := myArm.IsMoving(context.Background())
logger.Info(is_moving)

For more information, see the Go SDK Docs.

Parameters:

None.

Returns:

Future<bool>

Example:

var isItMoving = await myServo.isMoving();

For more information, see the Flutter SDK Docs.

Stop

Stop the servo from moving. Supported by viam-micro-server.

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:

None.

Example:

my_servo = Servo.from_robot(robot=robot, name="my_servo")

# Move the servo from its origin to the desired angle of 10 degrees.
await my_servo.move(10)

# Stop the servo. It is assumed that the servo stops moving immediately.
await my_servo.stop()

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:

(error): An error, if one occurred.

Example:

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

// Stop all motion of the arm. It is assumed that the arm stops immediately.
err = myArm.Stop(context.Background(), nil)

For more information, see the Go SDK Docs.

Parameters:

extra Map<String, dynamic>? (optional)

Returns:

Future<void>

Example:

await myServo.stop();

For more information, see the Flutter 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 servo and add features that have no built-in API method, you can access them with DoCommand.

Flutter

Parameters:

command Map<String, dynamic> (required)

Returns:

Future<Map<String, dynamic>>

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.

GetResourceName

Get the ResourceName for this servo with the given name.

Python
Flutter

Parameters:

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

Returns:

(viam.proto.common.ResourceName): The ResourceName of this Resource.

Example:

my_servo_name = Servo.get_resource_name("my_servo")

For more information, see the Python SDK Docs.

Parameters:

name String (required)

Returns:

ResourceName

Example:

// Example:
var name = Servo.getResourceName('myServo');

For more information, see the Flutter SDK Docs.

Close

Safely shut down the resource and prevent further use.

Python
Go

Parameters:

None.

Returns:

None.

Example:

await my_servo.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:

myServo, err := servo.FromRobot(machine, "my_servo")

err = myServo.Close(context.Background())

For more information, see the Go SDK Docs.

Have questions, or want to meet other people working on robots? Join our Community Discord.

If you notice any issues with the documentation, feel free to file an issue or edit this file.

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