Go Logitech Litra Glow Driver

This GO module implements a basic way to interact with a Logitech Litra Glow light. It uses karalabe/usb for the low level USB communications. I have only tested this on Linux.

The reverse engineered USB protocol comes from the kharyam/litra-driver Python implementation.

UDEV Config

Before you can use the light on Linux as a non-root user, you need to set up the following UDEV rule in /etc/udev/rules.d/82-litra-glow.rules:

SUBSYSTEMS=="usb", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c900", MODE:="0666", GROUP="plugdev"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c900", TAG+="uaccess"
KERNEL=="hidraw*", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="c900", TAG+="uaccess"

Then restart UDEV to refresh it rules as root:

udevadm control --reload-rules && udevadm trigger

And then (re-)plugin your light again.

Usage

Obtain the driver with:

go get derickr/go-litra-driver

Import the driver in your .go file:

import derickr/go-litra-driver

In order to use the driver to control the light, create a new instance of the LitraDevice struct:

ld, err := litra.New()

Currently, the driver only supports one light. If the driver can't open the USD device, an error will be returned.

You can then use the ld variable as a handle to issue control statements.

Task	Method	Arguments
Turn Light On	ld.TurnOn()
Turn Light Off	ld.TurnOff()
Set Brightness	ld.SetBrightness(level int)	level is brightness from 0 to 100
Set Temperature	ld.SetTemperature(temp int16)	temp is light temperature from 2700K to 6500K
Close Connection	ld.Close()

If you supply an out-of-range value to SetBrightness or SetTemperature it clamps to the supported range.