What makes this MP3 Player Tick
The system mother board features a 100 Mhz side bus with an Intel Celron Processor running at 366 Mhz. Stay away from non-intel chips as they can not handle the decompression of the MP3 Files as smoothly. I've read that a pentium 75 is minimum, so an old 486 isn't going to make it happen (too bad as there are lots of those floating around!). The board also has it's own sound, video, modem and lan built in. There are 64 Megs of RAM to play in and currently the OS is Win98. The MP3 player software is Winamp of course! It allows for the coding of plug-ins and has some great playlist features.
Other hardware includes a 9.6 Gig Hard Drive (bottomless pit!) to store all of the 2200+ MP3 files. I have also added a Sound Blaster 128 because as I've said elsewhere, the onboard sound is not quite good enough. : )
Fine Tuning the Setup
Using Win98 as the OS in a system that isn't powered down properly can cause the scan disc to run on every boot. Windows likes to write all system changes as you log off. (This is why your changes are never saved if you crash before logging off.) In this situation you boot windows & Winamp and when you are finished you shut off the main power. Since all you are doing is playing files, there should be no writing to the drive anyway. (However this is windows we are talking about... who knows?) I simply installed "Tweak UI" from the power toys section of the Win98 CD. It becomes part of your control panel. Inside there is a setting to disable scan disc at start up. A simple fix... Also, in the windows system.ini file I changed the default shell (explorer) to Winamp. This means that only Winamp is available after booting and cuts down a bit on the overhead of explorer.
Updating the Files:
Another item that was taken into consideration when constructing this monster was how to add / remove tracks. I could have gone with an Ethernet connection, but as I do have that ability on the work PC, I don't have it on the home PC. Since I am using my home PC for recording my records, I needed a way that I could transfer directly to the MP3 player. Enter Symantic's "PC Anywhere." - absolutely my favorite utility for the PC. Not only does it permit file transfers between two computers connected by a cable between the parallel ports, it also allows for complete remote operation of the other PC. This means I don't need a monitor, mouse or keyboard to plug into the player.
Making MP3's from CD's
- There are a zillion programs out there that allow you to grab the audio from your CD's. Audio Grabber being one of my favorites. The grabbed files are stored as .wav files and need to be processed and compressed into MP3 format. Xing has by far the fastest and most popular encoding software to date. So good are these two programs, that they combined into one piece called "Audio Catalyst". They have made crunching your CD collection into MP3's a breeze. My 400 Mhz system at work can process an average CD (ripping, compressing, and saving each track) in about 15 Minutes. Your only limitations are the size of your hard drive (and they say size doesn't matter!) and the number of CD's in your collection.
Making MP3's From Records
- If you are like me and hung on to that vintage vinyl collection - then "more power to you!" I bet if you have moved around at all - you have a few "Record Size Milk Crates" taking up space... The trick is - how do you pull all of the tunes you love into the PC? There are many ways to do this. It is just like making tapes (with a few more steps). Since this process is converting analog signals into digital, you can only work in real time. By that I mean - you have to play each album! (a bit different than compressing your CD collection.) At first I used Wave Lab. I connected my home stereo's recording output to the 'line in' on my PC's sound card. Then I set the levels using the software mixer. When it was ready I pressed record and dropped the needle. You should have seen me. Jumping back and forth from the PC to the Turn Table trying to catch the start and end of songs. I have a cordless mouse - so I would take it across the room with the pointer on the record button, depress the button - drop the needle and release! This worked great - but paying attention to the start and finish of each track became monotonous. Then I realized I had a rather large hard drive in the PC, and made some room so that I could record the entire side of an album at a time. This worked great. I would cut and paste parts of this HUGE wave file into individual tracks and save the wav files. Recently I remembered I had this program that came with my CD burner software. It's on the Easy CD Creator Deluxe Edition from Adaptec and it's called "Spin Doctor". This is a gem. It not only records 1/2 an LP at a time, it also removes pops & crackles then breaks the the album into individual tracks. What more could you ask for? To make these wave files into MP3 format, use explorer to drag the group of them into audio catalyst and you can normalize and compress at the same time by choosing both from the selection box.
Remote Operation Without a Screen
The clever ones among you will be asking yourself - how does he find the songs he wants to hear? Simple really (as always there is a simple answer!) A couple of different methods work well... First off, when building the MP3 file database I made sure to have Artist, TRACK and album information stored in each file name. The track number is important. Lots of albums flow between tracks and require playing in a certain order (Pink Floyd is a good example). Winamp will sort a directory of files alphabetically. If the track numbers are not there then the album tracks remain grouped together in the list but in alphabetical order, not the original playing sequence. Second, I have a small booklet that I print up listing the tracks and their numbers, providing a simple reference if I want to hear something specific immediately. However in practice I use the system in an entirely different manner. First I set it to shuffle. Then I skip around until I hit a track I "feel" like listening to. I then turn off the shuffle feature and let the track(s) play from there. I also use the playlist features of Winamp to create special groups of tracks I like to hear a specific times. These are classed by moods and the songs contained within are chosen accordingly.
The remote control handles all of the playing features of Winamp. I can Play, pause, stop, skip forward a track, backward one track, forward ten tracks, backward ten tracks, adjust the volume, load playlists and jump to any track directly by keying in it's track number.
I could have continued the project and installed a backlit LCD screen and coded a plug-in to display the track information but remember - I didn't want to make visual modifications to the interior of the car. Maybe someone can tell me how to interface with the LCD readout of the in-dash player? : )
Even seeing the IR receiver bugs me - I might open the box and extend the connection to the IR diode - installing it somewhere where I-can't-see-it-but-it-can-see-me while hiding the box completely... (more work!)
IR Receiver
- This little item was the clincher for me. I had pondered this project for quite a while before taking action, but when I found out there was someone offering an IR receiver that also had a plug-in available for Winamp - that was it! You can find out more by visiting the people who make them: Evation. I purchased it over the net with Visa and was told it would arrive in 2 - 3 weeks. It was in my paws 4 days later - customs inspected - straight from the Netherlands! (no wonder it was customs inspected!) This little box requires the use of a serial port for its operation. It can decode just about any remote control's IR signals. (the real geeks will try to use their palm pilots and zaurus's) Hmmm - I must be a real geek then as I just realized I can set up the play list as a text file and double click my way to any track... except I need one hand for the steering wheel and I like to keep my eyes on the road. Besides the remote's operation was memorized within 20 seconds of use...(it's a remote ( : )
Serial Port Extension
If I remember correctly not all of the wires in a nine pin serial port are used. However, instead of figuring this out I felt it was easier just to make an extension that included all nine wires. Not wanting to spend an eternity searching for a multi conductor wire I grabbed a length of six conductor bell wire and doubled it up. After this was fed through the car's wiring harness, I attached the appropriate 9 pin connectors to each end. These are available at your local electronics parts store. They are called Sub-D connectors. You will want one male and one female 9 pin Sub-D connectors, complete with hoods. A simple job requiring a little soldering. The wires are colour coded. Attach the wires one at a time to the pins of one connector. Then wire the second connector by making sure that the wires are connected in sequence. Pin one of the female connector (say the upper left hole facing the connector) should be connected to the pin of the male connector that would plug into pin one of another female connector. Hard to put into words, sufice it to say - you are making an extension cord. Each pin has to connect to the same hole on the opposite end of the cable.If you want the IR unit plugged in at the other end of the cable to work, ensure that you make the right connections! I suppose that you could find a ready made cable - but that wouldn't be as much fun - and it wouldn't be the right length - either too long or too short.
Changing The Audio Source
Not every in-dash unit has an auxiliary feed for audio. Since my unit is also a controller for a CD changer - it did have an input for the CD's audio source. A simple relay switched circuit allows me to change between the CD player's audio or the MP3 player's audio. Using a push button switch mounted in the middle console, I can turn the relay on or off, changing the audio source. Of course I have to have my in-dash unit set to play CD's to activate the CD audio in on the unit. This means that the CD changer has to have CD's in it and be playing all the while I am listening to MP3's. Now if only I could get the LCD read out on the in-dash unit to scroll the track information from Winamp instead...
To build this circuit you will need a suitable relay as detailed
here, as well as a "single pole / single throw" push button or toggle
switch. The 12V+ wire comes from any + side contact in the fuse pannel and is
connected directly to the relay. The 12V- comes from any ground source and is
connected one side of the switch and the other side of the switch is connected
to the 12V- side of the relay. For those not familiar with realys, it is a
multi contact switch that exists in two states: NC - Normally closed (this is
the active circuit when no power is fed to the relay) and NO - Normally Open
(active when power supplied to relay). In the diagram Audio A would be the NC
circuit and Audio B the NO, thus you would have to switch on the power to the
relay to activate Audio B. (Wordy but I think it makes sense...) The output is
the Common or CO side of the circuit - meaning it is common to both circuits
and in this case feeds the selected audio into the AM /FM Radio Cassete Deck.
You must have at least ONE input available on your car's stereo to make this
work, remember that this deck is also a CD Changer controller, and thus
has an audio input.
DC to AC inverter
These little gadgets work great. As the PC power supply can output 250Watts, it makes sense to get an inverter that can handle that type of load with a little spare room. I chose a 300Watt model that can handle short peaks of up to 500W. Read your manuals! Anything that will be drawing constant power must be hardwired to the car. Don't use a cigarette lighter socket! The connections are not as pure as hardwiring, and bumpy roads can jar them loose. Your PC loves constant power!
Choosing to use a DC to AC inverter to run the PC's power supply over building a 12V DC to PC level power supply was simple. First, I didn't want to build a dedicated power supply! Second, I wanted portability - music that can go anywhere - by using the inverter for the car, I can still plug the PC power supply into a regular 115V outlet and hook the box up to the stereo.
Eliminating Ground Loops
A Ground Loop is simply that. When a couple of powered items are hooked together a physical loop through the ground connections can add a nasty hum to the audio. A buzzing sound would be a better description. Most automobiles are wired with a negative ground, which means that the body of the car is one side of any circuit - the negative side(!) Since your amplifier, MP3 player and the in-dash unit all have different connections to ground - they may create a ground loop and that dreaded buzz. I have used a Ground Loop Isolator (available at audio shops) in-line with the audio feed to the amplifier, but it only slightly lowered the noise. I left the unit in and searched for a better solution. The more audio components that connect to the same ground the better. I attached a separate ground wire shared with the amplifier and the inverter with a wire to the PC power supply's case and that seemed to eliminate all extra noise. It is taken from the amplifier's power contacts when feeding the inverter 12V. The inverter does not generate a pure voltage waveform either and this can also add to the noise problem.
Power Switch
Sounds simple doesn't it? This is a must have in the front of the car. How else can you power up the MP3 Player? When you turn the ignition key - the car drains so much juice from the battery that the inverter will quit or go into overload mode. The power switch is used for turning on the player after the car has started. It is also used for removing power to the inverter when the car is shut off. If you don't turn off your inverter when the car is off - you will drain the battery after about three hours. (I did need a jump start once during the testing phase - as I forgot to shut the system down and left it on over night!) I plan to install a small light-green LED in the dash alongside the other LED indicators in the car (there are two empty spots). It could simply be lit when the power to the system is on, thus reminding the driver (me) to shut it off!
Providing power to your system/inverter is quite easy. Simply run a wire from the positive terminal of the battery to the location of your system. Since you will be pulling a lot of current for the amplifier, inverter and computer it is important to use a heavy gauge (12 - 14) wire. Ensure that you install an inline fuse (16 amp should be fine) at the connection to the battery. The wire is routed past any critical engine parts (follow existing wires if you can), and then fed though the fire wall arriving somewhere above the operator pedals. There should be an access port that you can feed the wire through to get from the engine compartment to the interior. An alternative would be to find an available fuse slot in the fuse pannel and take the power from there. Remember in most cars the body of the car is the negative side of any circuit. This means you only have to run a single conductor. The wire needs to be run to one side of a "single pole / single throw" switch that is accessible in the front onf the car. Then, a second wire will continue from the other side of the switch all the way to the amplifier & inverter. I have used an inline connector just before the inverter to enable me to easily connect & disconnect the power feed.
Muffin Fans
Last but definitely not least, cooling the unit. Most PC's sit in air-conditioned comfort at home or the office and don't meet with extreme weather. The trunk of a car can get extremely hot in the summer and it is essential to have good circulation for the computer. The two muffin fans pictured here plug into the inverter and constantly fill the box with fresh air while venting out the wire port. The inverter and the PC's power supply both have fans of their own, so I imagine there is quite a whirlwind happening inside the box. I have made all cables long enough to allow the MP3 player to sit on the back seat as well. I have a hunch that it won't like the Canadian 30 below weather come January.
More?...
Didn't find all the answers you were looking for? Try the feedback page - if I get requests for things that should be covered, I'll include them here.
Well I hope you have found all of this helpful and if nothing else interesting. Mad? Maybe. Let me say in my defence...
"What would you like to hear today?" : )
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