MP3 Jukebox

In case you are unfamiliar with the CAJUN, it's a Car Audio Jukebox running under UNix. Why name the project CAJUN, you ask? My guess is that CAJLI just sounded dumb. :) The basic idea of the project is to create an mp3 jukebox, using Linux as the OS (you don't your jukebox BSOD'ing, do you?), that you can put in your car.

I started on mine after reading Paul Bournival's page (which I believe was a slashdot link). I got the idea in my head that I could use one of those crazy things. So here i am, almost two years after completing mine and I'm very happy with it. Especially since the release of 3.0.6 which supported playlists.

The directions off the CAJUN page and Matrix Orbital pages are relatively simple to follow, but leave it to me to screw them up. I fried my frist LCD display by accidently wiring power to pin 1 instead of pin 9 – D'Oh! I fixed that up right straight, but the new one still wouldn't work! It turns out that the display wouldn't power up without ground and Vcc being on the same bus. Probably due to the fact that the potential differences between the IDE power and serial port ground (pin 5) wasn't quite 5V. So, I just hacked up a 4 pin power cable for Vcc and ground. Viola! It powered up just fine. The CAJUN software was a snap to install and get running too. All I had to do was make sure that xaudio was installed and to tell it where to look for the .mp3s.

So now I have all my CDs encoded onto the CAJUN, with a couple of playlists going. Now all I need is a car with a trunk that doesn't leak, then I'll be in business!

As soon as I can borrow a digital camera, I'll snap some pictures of the CAJUN with it's Welfare ™ wiring.

My mini CAJUN HOW-TO

Before the HOWTO begins, I want to make a few comments:

  • A soundcard >=16 is recommended because those cards support a mixer.
  • You may also want to throw a network card in the pc too, for faster .mp3 xfers
  • Yes, there is LIRC/IR support for the CAJUN, but I've yet to mess around with it. Though I really want to. If you decide to go this route, you may want to save $40 and get the MO LK204 w/o the keypad support.
  • There are other supported keypads and displays supported, check the CAJUN page for more details.
  • Feel free to e-mail me with any questions, just log into the LUG page and mail me (John Roberts, memberid 8).
  • There is also FM support to make it a fully functional in-dash type head unit, again check the CAJUN page for more info.
  • If you plan on using the CAJUN in an automobile, you will want a power inverter. DigiKey sells one as part number PV-125.

There are a few basics that you'll need here:

  1. A CPU ( >= Pentium 75 – although some say a 486DX100 works)
  2. A motherboard for said CPU
  3. RAM (32 recommended)
  4. An LCD Panel… for this example a Matrix Orbital LK204-25 (With keypad support)
  5. A keypad to attatch to the keypad controller on the LCD ( I used a Greyhill GH5001-ND from DigiKey )
  6. A RadioShack project box to house the keypad and LCD
  7. 9Pin Serial cable ( to string from project box to where-ever)
  8. A 1-Amp slo-blo fuse and inline fuse housing (Hit up RadioShack)
  9. A 40pin IDE cable
  10. A sound card (preferably something >= SB16)

Step one, naturally, is to assemble the PC and put it in the enclosure of your choice. Anything from a pizzabox to a real pc case is fine. Just remember it has to sit in your car, or in your entertainment center.

Step two, install Linux, xaudio, and the CAJUN software. I can't emphasize this step enough. The think just will NOT work without an OS. I really can't recommend partition sizes here, other than to give the majority of the space to something like… /mp3 :). Also, don't forget to edit the cajunrc file located in the 'lib' subdirectory of whereever the CAJUN was installed.

Step three, make LCD go now. NOTE: BE SURE POWER TO THE SYSTEM IS OFF AT THIS POINT! This is where it can get tricky. If you're reasonably handy with a penknife, you'll be fine. If you have an AT form-factor motherboard, the serial ports are just a faceplate and have ribbon cables that plug directly into the motherboard. NOTE: If you have an ATX case, you'll have to either hack up the back of the port, or hack up a cable on the exit end of the port. Now, for the AT cases, splice out pin 5 (the middle wire) and pin 9 (the wire OPPOSITE the red one). I recommend splicing them out as close to the motherboard connector as possible, that way loose ends aren't flapping around possibly causing shorts. Now, grab a spare 4 pin drive connector and splice the black wire (ground) to pin 5 from the serial cable, and splice the red wire (5V DC) to pin 9. I would NOT recommend doing this without the 1Amp inline fuse, mentioned in the parts list above, between. Just safer in case of a surge. I'll try to get some pics in here soon.

Step four, power the system back on and connect the LCD panel to the serial port you just hacked up. NOTE: MAKE SURE THE WIRING IS COMPLETE WITHOUT BARE WIRE SHOWING! If everything thus far is ok, the Matrix Orbital display backlight should come on and the BIOS welcome screen should show up. If not, something is wrong. Double check the wiring and the connection from the 9Pin serial port to the 9pin connector on the back of the LCD panel.

Step five, and the most annoying, is to make keypad go now. This step could well take the longest of them all. From here on in it's just trial and error. Take the spare IDE cable and your trusty penknife or convenient cutting utensil. Find the middle of the connector (lengthwise - to make 2 2×10 ribbon cables) and cut both connector ends in half, then you should be able to pull the cable apart. Congratulations, you have just made your LCD to keypad cable. The keypad connector on the back of the LCD should have a row of 10 pins. You should have two rows of 10 pins on the connector. Line up one row and plug it in. Fire up the CAJUN software you installed in step 2. Now here's the fun part. Keep trying combinations of pins on the other end of the connector until pressing the 1 key does what pressing the 1 key should do. If you've got a short attention span or no patience get a friend with patience/an attention span to do this for you. You may want to pay them a beer/soda for their troubles though.

Step six, At this point you have +5V going through your serial port to a working LCD panel and keypad combination and Linux with xaudio and the CAJUN software installed. Now all you have to do is get the media onto the cajun! I reccomend the 100MB ethernet method, but feel free to use whatever method you decide is best.

Step seven, you have the CAJUN installed with a working LCD/keypad and media on your new machine. So what are you doing still reading this? Enjoy some .mp3s, dammit!

Copyright 1999-2000 © John Roberts

tux