PowerMate

A Node-Red node to read from the Griffin PowerMate

Install

Run the following command in the root directory of your Node-RED install

npm install node-red-contrib-powermate

Usage

This node outputs messages for 3 different events

• Button down
• Button up
• Wheel rotation

For the first 2 the message payload of 'up' or 'down' respectively is published to the topic + '/button'. For the wheel rotation the message payload is +ve for clockwise and -ve for anti-clockwise on the topic + '/wheel'

Permissions

Depending on OS, you may get an error that looks something like

cannot open device with path 0001:0004:00

If this happens, it is likely because your user doesn't have permissions for the PowerMate device. In Linux (specifically Raspbian), creating the file /etc/udev/rules/95-powermate.rules and entering the following text:

SUBSYSTEM=="usb", ATTRS{idVendor}=="077d", ATTRS{idProduct}=="0410", SYMLINK+="powermate", MODE="660", GROUP="input"

will assign the PowerMate device to the "input" group, which the pi user belongs to. For other OSs, change the GROUP entry to a group that your user belongs to.