Python 3 relay toggle for Moode Audio

Instructions

Change the relay pin to the GPIO pin for your relay.
Save the contents of relaytoggle.py script to /home/pi/relaytoggle.py
Save the contents of relaytoggle.service script to /lib/systemd/system/relaytoggle.service
Run the following commands
    sudo systemctl enable relaytoggle
    sudo service relaytoggle start

relaytoggle.py

#!/usr/bin/env python3

import RPi.GPIO as GPIO
import os
import time

defaultDelay = 5 #seconds 
relayPin = 2 # GPIO pin in BCM
currentState = False # the current state

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(relayPin, GPIO.OUT)

def isRunning():
    return "RUNNING" in os.popen('cat /proc/asound/card*/pcm*/sub*/status | grep RUNNING').read().split()

while True:
    if isRunning() and not currentState:         
        GPIO.output(relayPin, 1)
        currentState = True
        print("Relay Activated")
        time.sleep(defaultDelay)
        
    elif not isRunning() and currentState:   
        # delay again on playback stops to account for track changes
        time.sleep(defaultDelay)
                
        if isRunning():
            # if it's running don't deactivate the realay   
            print("Playback resumed, cancelling deactivation")
            continue
        else:
            # deactivate the relay
            GPIO.output(relayPin, 0)
            currentState = False
            print("Relay Deactivated")                                     
            
        time.sleep(defaultDelay)
    else:
        print("No State Change...")
        time.sleep(defaultDelay)        

relaytoggle.service

[Unit]
Description=MoOde Relay Toggle Daemon

[Service]
Restart=on-failure
WorkingDirectory=/home/pi
ExecStart=python relaytoggle.py
ExecReload=/bin/kill -HUP $MAINPID
KillSignal=SIGINT

[Install]
WantedBy=multi-user.target

I have some problems with this script. When I start playing music, nothing happens. Only when I stop playing music the state of the relay changes after 5 seconds.

I think it may be because your relay is wired for normally closed, or is a normally closed relay, so it opens in the high state.

If it's wired for normally closed and you have the option, wire it for normally open.

If that's not an option, invert the GPIO.output(replayPin, 0) with GPIO.output(replayPin, 1) and vice versa.

Hi

Thanks for uploading this. It works like a dream.

I tweaked the Python script a little bit, to use a simple state machine. This way I can set the the pinout is set to one (turbine the amplifier on) after e very short time (in this case - 1 second), And the Amplifier stays on for a longer duration (60 seconds in this case) after playback stops. This means that the amplifier wont turn off, even if I pause the music for a short while (for instance if my wife asks me a question)

I'm new to Github, so I'm not sure if I should create a fork or how else the share my scripts. Suggestions are welcome

Hi

Thanks for uploading this. It works like a dream.

I tweaked the Python script a little bit, to use a simple state machine. This way I can set the the pinout is set to one (turbine the amplifier on) after e very short time (in this case - 1 second), And the Amplifier stays on for a longer duration (60 seconds in this case) after playback stops. This means that the amplifier wont turn off, even if I pause the music for a short while (for instance if my wife asks me a question)

I'm new to Github, so I'm not sure if I should create a fork or how else the share my scripts. Suggestions are welcome

Hey!
I want to see your version if possible - seems like it's doing the thing that I'm searching right now.
You can fork this Gist, and edit it, in this way you will make a new revision. If you want, you can modify the Instructions to give a credit to the original creator :)