periph-servo-pca9685

periph-servo-pca9685 is a Viam modular component that uses the periph.io library to control servos connected to pca9685 channels.

API

The periph-servo-pca9685 resource provides the following methods from Viam's built-in rdk:component:servo API:

Move(angle uint32)

Position()

Stop()

Viam Component Configuration

The following attributes may be configured as periph-servo-pca9685 config attributes. For example: the following configuration set up a servo on I2C bus 0, PCA9685 channel 15:

{
  "i2c_bus" : "0",
  "channel" : 15
}

i2c_bus

string (default: "0")

The name or number of the I2C bus to which the PCA9685 is connected.

i2c_addr

string (default: "0x40")

The number of the I2C address to which the PCA9685 is connected. This can be formatted as hex (prefixed by "0x") or base 10 (unprefixed) values.

If you're not sure which address to use, see [this guide] for how to detect i2c devices. i2cdetect displays the hex formatted value.

channel

int (default: 0)

The channel (0-15) to which the servo to control is connected.

frequency_hz

int (default: 50)

The frequency in hz of the servo to control. See the datasheet for the servo to control.

min_angle_deg

int (default 0)

The minimum angle in degrees to which the servo will be allowed to move.

max_angle_deg

int (default 180)

The maximum angle to in degrees which the servo will be allowed to move.

starting_position_deg

int (default 0)

When the servo is initiated, it will move to this position (in degrees).

min_width_us

int (default 500)

The minimum duty cycle width in microseconds. See the datasheet for the servo to control.

max_width_us

int (default 2500)

The maximum duty cycle width in microseconds. See the datasheet for the servo to control.

Development

To release a new version of this module, this repo uses the Viam build-action to build the module in Viam's cloud infrastructure and deploy the new version based on a tagged release.

To kick off a deployment:

1. Tag the release commit with the new module version and push it to the repo
2. Create a release based on that tag

Within a couple of minutes, the new module version should be published to the Viam registry.

If there is an issue with the action and a manual release is required:

1. Authenticate the Viam CLI:

   viam auth login

2. Start a remote build for the new module version

   viam module build start --version <version>