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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 hobby servo precisely or getting its current status.

Industrial servos should use the motor API which provides more features than the servo API.

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.
`GetGeometries`	Get all the geometries associated with the servo in its current configuration, in the frame of the servo.
`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.
`Close`	Safely shut down the resource and prevent further use.

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=machine, 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:

angleDeg (number) (required)
extra (None) (optional)
callOptions (CallOptions) (optional)

Returns:

(Promise)

Example:

const servo = new VIAM.ServoClient(machine, 'my_servo');

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

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

For more information, see the TypeScript SDK Docs.

Parameters:

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

Returns:

Future

Example:

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=machine, 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 (None) (optional)
callOptions (CallOptions) (optional)

Returns:

(Promise)

Example:

const servo = new VIAM.ServoClient(machine, 'my_servo');

// Get the current set angle of the servo
const pos = await servo.getPosition();

For more information, see the TypeScript 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=machine, 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.FromProvider(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:

callOptions (CallOptions) (optional)

Returns:

(Promise)

Example:

const servo = new VIAM.ServoClient(machine, 'my_servo');

const moving = await servo.isMoving();
console.log('Moving:', moving);

For more information, see the TypeScript 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=machine, 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.FromProvider(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 (None) (optional)
callOptions (CallOptions) (optional)

Returns:

(Promise)

Example:

const servo = new VIAM.ServoClient(machine, 'my_servo');

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

// Stop the servo. It is assumed that the servo stops moving immediately
await servo.stop();

For more information, see the TypeScript SDK Docs.

Parameters:

extra Map<String, dynamic>? (optional)

Returns:

Future

Example:

await myServo.stop();

For more information, see the Flutter SDK Docs.

GetGeometries

Get all the geometries associated with the servo in its current configuration, in the frame of the servo. 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.

Python

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:

(List[viam.proto.common.Geometry]): : The geometries associated with the Component.

Example:

my_servo = Servo.from_robot(robot=machine, name="my_servo")
geometries = await my_servo.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. Most models do not implement DoCommand. Any available model-specific commands should be covered in the model’s documentation. If you are implementing your own servo and want to add features that have no corresponding built-in API method, you can implement them with DoCommand.

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:

my_servo = Servo.from_robot(robot=machine, name="my_servo")
command = {"cmd": "test", "data1": 500}
result = await my_servo.do_command(command)

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.
cmd (map[string]interface{}): The command to execute.

Returns:

(map[string]interface{}): The command response.
(error): An error, if one occurred.

Example:

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

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

For more information, see the Go SDK Docs.

Parameters:

command (Struct) (required): The command to execute. Accepts either a Struct or a plain object, which will be converted automatically.
callOptions (CallOptions) (optional)

Returns:

(Promise<JsonValue>)

Example:

// Plain object (recommended)
const result = await resource.doCommand({
  myCommand: { key: 'value' },
});

// Struct (still supported)
import { Struct } from '@viamrobotics/sdk';

const result = await resource.doCommand(
  Struct.fromJson({ myCommand: { key: 'value' } })
);

For more information, see the TypeScript SDK Docs.

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.

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:

None.

Returns:

(Name)

Example:

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

err = myServo.Name()

For more information, see the Go SDK Docs.

Parameters:

None.

Returns:

(string): The name of the resource.

Example:

servo.name

For more information, see the TypeScript SDK Docs.

Parameters:

name String (required)

Returns:

ResourceName

Example:

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

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:

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

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

For more information, see the Go SDK Docs.

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