1. Linux Jukebox Project Presented by: Andrew Dumitrascu Murray Saul

2. Linux Jukebox Project  Background: Faculty member purchased wall-mount jukebox 20 years ago. The wall-mount jukebox was popular in restaurants in the 50s, 60s and 70s. The device is a remote-control device to select songs to be played on a remote record player or centralized computer.

3. Linux Jukebox Project  Objective: Connect Jukebox to CPU to play MP3s or other types of audio files… There is a commercial solution in the U.S. which costs $129 (US) for the appropriate “black-box” converter and software (MS-Windows only). Linux club wanted to see if they could provide an open source solution using Linux OS without using a “black-box” (e.g. serial cable connection).

4. Linux Jukebox Project  Required: Wall-mount Jukebox (AMI W-120) CPU with soundcard running Linux OS Serial cable Power transformer for Wall-mount jukebox Wall-mount jukebox manual (obtained over the Internet) Drill to “drill-out” lock … it didn’t come with a key!

5. Linux Jukebox Project  How a Wall-mount Jukebox Works:  According to AMI W-120 manual: Wall-mount jukebox sends out a series of low- voltage direct current pulses to a receiver (e.g. central player or central computer). The number and spacing between these pulses are determined by what selections are made by user (i.e. which buttons were pressed).

6. Linux Jukebox Project  The Solution: 1. Connect portion of serial cable to send electronic pulses to CPU 2. Write a bash-shell script to: Record the timings of the pulses and store in a file. Calculate the difference in the pulses Access another file and parse song information regarding the pulse timing difference (train info) and add song’s pathname to a song file. Run an MP3 player to play MP3s that are queued in the song file. Continually check every 5 seconds to see if any songs are queued for playing

7. Linux Jukebox Project  Files: 1097186586.976415000 1097186587.049701000 1097186587.119054000 1097186587.190131000 1097186587.259130000 1097186587.332167000 1097186587.408929000 1097186587.568426000 1097186587.640651000 rawrite Contains the timing of the first and second train. Train data in this file will be used to help determine which selection was made. Actually, 2 series of pulses are sent to CPU. The differences in these times provide information for a song sequence (referred to as a train)

8. Linux Jukebox Project  Files:  1 Train1:2 Train2:1 01-Meng_Tian.mp3  2 Train1:2 Train2:2 01_-_Fatboy_Slim_-_Don't_Let_The_Man.mp3  3 Train1:2 Train2:3 01_-_Tangerine_Dream_-_Prime_Time.mp3  4 Train1:2 Train2:4 02-Summer_in_Shauxi.mp3  5 Train1:2 Train2:5 01_Engelbert_Humperdinck_-_Release_Me.mp3 songs Contains information regarding the trains, and MP3 filename to be parsed and played when train is determined Train information is associated with a particular MP3 file…

9. Linux Jukebox Project  Files:  Meng_Tian.mp3  Fatboy_Slim_-_Don't_Let_The_Man.mp3  Tangerine_Dream_-_Prime_Time.mp3  02-Summer_in_Shauxi.mp3  01_Engelbert_Humperdinck_-_Release_Me.mp3 queue Contains pathnames to songs that MP3 player has been configured to read from…

10. Linux Jukebox Project Shell Script (Part I): Setup & Declare functions stty -clocal time=$(date +%s.%N) train=0 #Start the player to look for songs in the queue /root/jukebox/playmusic & CID=$! trap "kill -9 $CID; exit 0" INT #Put the time into a temporary file to be retrieved later... capture() { echo "Starting step 1...." /root/jukebox/step1 > /tmp/rawtime & echo "End step 1....." }

11. Linux Jukebox Project Shell Script (Part II): Record Timed Pulses #Start an infinite loop while [ true ] do train=0 pulse1=1 pulse2=1 #Call the capture function to capture the incoming electrical pulses capture < /dev/ttyS0 #Sleep for 2.5 seconds to avoid accidentally capturing a final pulse #that sometimes get sent at the end. # usleep 2100000 sleep 5 #End the pulse capture program killall step1

12. Linux Jukebox Project Shell Script (Part III): Calculate the “Trains” #Start the time processing to calculate the number of pulses sent. for input in $(cat /tmp/rawtime) do diff=$(echo "$input $time" | awk '{print int(($1-$2)*1000)}') echo $diff if [ $diff -gt 100 ] then train=$((train+1)) elif [ $diff -gt 20 ] then if [ $train -eq 1 ] then pulse1=$((pulse1+1)) else pulse2=$((pulse2+1)) fi time=$input done

13. Linux Jukebox Project Shell Script (Part IV): Play MP3 Song song=$(grep "Train1:$pulse1 Train2:$pulse2 " /root/jukebox/songs | awk -F' ' '{print $4}') if [ "$song" != "" ] then echo $song >> /tmp/queue fi Done # End of while loop # End of shell script

14. Linux Jukebox Project  Questions?