how to play sound on raspberry pi - after startup without login - node.js

Question

i need to play sound on the raspberry pi with a node.js script. Everything is fine when i'm starting the script from the commandline myself. When i run the same script after startup out of the /etc/rc.local script i see my running process when doing "ps aux" but i cant hear any sound. I also tried to start the node script after 40 seconds, because i thought that there was too less time for some initialization stuff or something, but within this time i could start the script from the command line and hear sound...
i tried both users: root and pi. They both work from the cmd (because the user that runs the script after the autostart is the root user)
i linked my programm to /usr/bin/node because if not the process wasnt able to start on startup.
i forced the raspberryPi to use the sereo jack: amixer cset numid=3 1
my node.js code is:
var fs = require("fs");
var lame = require("lame");
var Speaker = require("speaker");
var SerialPort = require("serialport").SerialPort;
var playing = false;
var stream = [];
stream[0] = "sound1.mp3";
stream[1] = "sound2.mp3";
stream[2] = "sound3.mp3";
stream[3] = "sound4.mp3";
var getCurrentStream = function(){
var i = Math.round( Math.random() * 3)
return stream[i];
}
var serialPort = new SerialPort("/dev/ttyACM0", {
baudrate: 9600
}, false);
serialPort.open(function(){
console.log("open");
serialPort.on("data", function(data){
console.log("data received"+data);
if(!playing){
try{
var currentStream = fs.createReadStream( getCurrentStream() );
var speaker = new Speaker();
speaker.on('finish', function(){
playing = false;
});
currentStream.pipe(new lame.Decoder()).pipe(speaker);
playing = true;
}
catch(e){
console.log("Error: "+e);
}
}
});
});
for the startup i tried:
as a cronjob, after crontab -e i attached:
#reboot /opt/node/bin/forever start /var/www/node/residenz/server.js
i also tried the same inside the file /etc/rc.local :
/opt/node/bin/forever start /var/www/node/residenz/server.js
thanks for any help!

Answer 1

I had the same problem, and this question (and analyzing the answer) gave me hope that it was possible, but for me it was the paths that was a problem - I was using a relative path but the working directory (and perhaps user?) being executed under cron needed the path to the file be absolute. BTW, I used cron, python, and pygame (pygame.mixer.music) and was able to make it work.
My testing program (pygame.mixer.Sound did not work but I believe that was because I was using an MP3 instead of a WAV)
import pygame
import time
import os
import sys
#soundFile = "alarm.mp3" # BAD
soundFile = "/home/pi/alarm.mp3" # GOOD
channel = None
if len(sys.argv) > 1:
pygame.mixer.init(44100, -16, 2, 4096)
if sys.argv[1] == "music":
print "Testing pygame.mixer"
pygame.mixer.music.load(soundFile)
pygame.mixer.music.set_volume(1.0)
pygame.mixer.music.play()
elif sys.argv[1] == "sound":
print "Testing pygame.sound"
pygame.mixer.init()
s = pygame.mixer.Sound(soundFile)
s.set_volume(1.0)
channel = s.play()
elif sys.argv[1] == "mpg":
print "Using mpg321 Player"
os.system("mpg321 " + soundFile)
else:
print "Using OMX Player"
os.system("omxplayer " + soundFile)
print "Execution control has returned"
while pygame.mixer.get_busy() or pygame.mixer.music.get_busy() or \
(channel is not None and channel.get_busy()):
continue
pygame.mixer.quit()
else:
print "Unknown option. Options are omx, mpg, music, or sound"
In cron, I had #reboot python /home/pi/soundtest.py music & and it played the file on boot up.

Answer 2

Just in case, that anyone else has the same Problem i want to share my final solution. I simply did the functionality with python. For the startup, i put the line which starts the python script into the file /etc/rc.local
#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# server.py
import RPi.GPIO as GPIO
import subprocess
import time
import serial
from random import randint
port = serial.Serial("/dev/ttyACM0", baudrate=9600, timeout=0)
PATH=[4]
PATH.append("/var/www/node/Boom1.mp3")
PATH.append("/var/www/node/Boom2.mp3")
PATH.append("/var/www/node/Boom3.mp3")
PATH.append("/var/www/node/Boom4.mp3")
def main():
count = 0
while True:
value=0
line = port.readlines()
if( len(line)!= 0 and count < 4 ):
try:
job=subprocess.Popen(["mpg321", returnPath()], stdin=subprocess.PIPE)
time.sleep( float(line[0])/10 )
except:
print("cant play soundfile")
def returnPath():
x = randint(1,4)
return PATH[x]
if __name__ == '__main__':
main()