midi-shutdown-server

midi_shutdown_server.py

A python script to create a midi device, and listen for control change messages to trigger shutdown.

import time
import mido
import os
import re

Also requires 'amidithru'

The script creates a virtual midi device (MidiShutdownServer), and listens to it for incoming midi control change messages.

Configurably, if it receives control change 64, with a value of 127, runs the shutdown command (sudo init 0).

There is logic built-in to check /proc/uptime and make sure the system has been up for at least 120 seconds (adjustable) before it will run the shutdown command.

This was done to hopefully prevent issues where, just after boot, something immediately sends the thing a signal and shuts your stuff down.

I use this as a listener to power down a Raspberry Pi running MODEP.

Generally, add an entry to your crontab to call the script on startup: (Make sure you set your path properly)

@reboot /usr/bin/sudo /path/to/midi_shutdown_server.py &

Note about sudo

This script requires root to run, so you need to call it with sudo, without password, or you can save the line in the root crontab, without the need for sudo.

To have this work on boot with sudo, you must not have sudo require a password to work.

You can achieve this by adding a new file and rule to your sudoers config. with visudo (username modep in examples):

sudo visudo -f /etc/sudoers.d/modep

Once in visudo, write the sudoers rule to allow your user to run sudo without a password:

modep ALL = (ALL:ALL) NOPASSWD: ALL

After that, you can log out and back in or reboot, and then be able to run sudo things without a password.