How to cast radios using Raspberry PI and use the phone as a remote

Raspberry Pi can be used for multiple purpose but this one of the most interesting: transform Raspberry PI to stream radio channel and use Android phone/tablet as a remote with the RS_player APP that you can download from here. 

You can understand how to use RS_player APP from this post.

I suggest to use raspberry PI zero w integrated wlan

with mini HDMI to HDMI adapter

and the HDMI to VGA adapter (with audio output)

the follow procedure is important to install in Raspberry all necessary SWs (from mac operative system):

1. install raspberryPI lite: 20xx-x-x-raspbian-stretch-lite.img. Download from this link: https://www.raspberrypi.org/downloads/raspbian/
2. flash the img in the SD card: Format before the card with Fat32 with disk utility
3. Use Etcher to flash the img in the sd card. Free download on https://www.balena.io/etcher
4. put the SD card in raspberry PI and connect with a HDMI monitor or using the VGA adapter to a regular monitor with VGA output
5. login using default user: pi and default password: raspberry
6. from terminal: sudo raspi-config
7. select "Interfacing Options" and Natigate and select SSH, choose yes
8. always in raspi-config, boot option, B1 Desktop / CLI, Console autologin
9. always in raspi-config, in network Options and after wi-fi, provide SSID and password of the home wifi
10. reboot raspberry and control if wlan is assigned using the command "ifconfig", after try to ping a webpage e.g. ping www.google.com to see if it is working
11. sudo apt-get upgrade, sudo apt-get updade
12. after try to connect with raspberry with ssh: ssh [email protected] where 192.168.X.XXX is the IP address assigned to raspberry
13. if you have the follow error "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!" write ssh-keygen -R 192.168.X.XXX
14. install FTP server with the follow istruction (from the file)
- sudo apt-get update
- sudo apt-get install vsftpd
- sudo nano /etc/vsftpd.conf and inside the file find uncomment:
     anonymous_enable=NO
     local_enable=YES
     write_enable=YES
     local_umask=022
     chroot_local_user=YES
and write at the end of the file:
     user_sub_token=$USER
     local_root=/home/$USER/ftp
save the file: CTRL-X, Y and ENTER.
- sudo service vsftpd restart
15. use filezilla to enter in raspberry and save files
16. sudo apt-get install vlc
17. sudo apt-get --purge --reinstall install pulseaudio
18. using ssh test the play with vlc:
cvlc http://dashitradio-de-hz-fal-stream06-cluster01.radiohost.de/dashitradio_128
19. sudo apt-get install python3-pip python2.7-dev
20. sudo pip install tornado
21. using FTP client (e.g.) FileZilla upload the folder "radioExec" in the folder /home/pi in raspberry. This folder is located here.
You need to unzip before
22. from ssh: add the follow line "/home/pi/radioExec/execRadio.sh &" at the end of the  .bashrc (located in the /home/pi). You can use for example nano (or vim) in ssh or update the modified file using ftp
23. reboot raspberry

Once this procedure is fulfilled, raspberry PI is ready to play radio streaming and activate server to receive commands from RS_player APP.

This is the main part of the code in raspberry pi to allow playing music and connection with android app with web-sockets commands

import tornado.httpserver
import tornado.ioloop
import tornado.options
import tornado.web
import tornado.websocket
import time
import threading
import subprocess, os
import signal


class LedHandler(tornado.websocket.WebSocketHandler):
        
    

    def check_origin(self, origin):
        return True

    def open(self):
        print("Connection opened from: {}".format(self.request.remote_ip))
        self.write_message("Connection opened")
        
    def on_close(self):
            print("Connection closed")

    def on_message(self, message):
        global run

        if run ==1:
            print("Message received {}".format(message))
            
            if str(message[:10]) != "Connection":
                if str(message[:4]) == "cvlc":
                    subprocess.Popen("/home/pi/radioExec/findkill_channel.sh", stdout=subprocess.PIPE, shell=True,preexec_fn=os.setsid)
                    time.sleep(2)
                print(str(message))
                subprocess.Popen(str(message), stdout=subprocess.PIPE, shell=True,preexec_fn=os.setsid)


def socketloop():
    global io_loop
    global server
    try:
        tornado.options.parse_command_line()
        app = tornado.web.Application(handlers=[(r"/", LedHandler)])
        server = tornado.httpserver.HTTPServer(app)
        server.listen(8000)
        io_loop = tornado.ioloop.IOLoop.instance()
        io_loop.start()
    except RuntimeError:
        print("server already on")


if __name__ == "__main__":
        global io_loop
        global server
        global run
        
        try:
            run = 0
            while True :
                if run == 0:
                    print("  Started")
                    run = 1
                    try:
                        server.stop()
                        io_loop.stop()
                    except:
                        print("Thread was already off")
                    our_thread = threading.Thread(target=socketloop)
                    our_thread.start()


        except KeyboardInterrupt:
            print("  Quit")