pypowermate

This module encapsulates access to the Griffin USB PowerMate "knob" device 1. The PowerMate is an "assignable controller" in the shape of a knob. The knob can be rotated, pressed and also features a LED at its base that can be used to indicate events to the operator.

This module provides functions to read knob events (rotate/press) and to write/set the LED brightness and pulse speed (when in "pulse"-mode).

The module interfaces with the device through the powermate Linux kernel driver and will therefore only work on Linux systems.

Getting started

For python3, just use python3/pip3 instead of python/pip2 in all command.

1. Install using pip:

   $ cd pypowermate-master
   $ sudo pip2 install .
   

2. Ensure "powermate" kernel module is loaded in your system. It ships with most modern Linux distros and should insmod automatically when you plug in the PowerMate.

   $ lsmod | grep powermate
   

3. Ensure your user can read/write the powermate input device. On Ubuntu, this means adding yourself to the "input" usergroup.

   $ sudo groupadd input
   $ sudo usermod -a -G input "$USER"
   $ echo 'KERNEL=="event*", NAME="input/%k", MODE="660", GROUP="input"' | sudo tee -a /etc/udev/rules.d/99-input.rules
   

then reboot

4. Testrun the example script.

   $ python examples/pulse_and_brightness.py
   

Depending on the exact model, you will have to change MinSpeed and MaxSpeed values.

API

See the documentation in pypowermate/powermate.py for details on how to use the module from your own code.

License

This module is licensed under GNU Lesser General Public License (LGPL v3). See LICENSE.txt for details.