The "DOS Head Unit"
By Hayden Smith, UK
Posted on October 2, 2006
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Installation

The next step is to install the parts in your car. As I used the stock head unit as the controller placing that in the car was easy. Being a non-smoker I used the ashtray as the home for my LCD screen. After that a simple MDF base was made to house the motherboard, PSU and hard drive in the glove box. While this could be tidied and potentially placed in the dash (I've a doubleDIN dash) the glovebox is never used anyway and made the perfect target location.

A caddy slot was made for the hard-drive so that it's easily removable from the carPC to slot into my desktop to update the music files there. It's possible to set a simple script to copy new files from a CD/DVD in the attached CD/DVD drive but as I didn't put one in I use the relatively simple method of updating via my PC.

Some shots of it installed. There's nothing really to see when it's playing except the text on the screen as above:

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Click to launch image viewer

Click to launch image viewer

Conclusion

This will give a cheap and simple music player. You just need to connect the speaker out from the motherboard to any processors you have or to your amplifier. You may or may not have noise and/or protection issues like this - I didn't but it depends on the amp/processor you are pairing the motherboard with. A solution is to use the motherboard's digital output into an external DAC/Processor (I've used a Nakamichi DAC101, you could equally use an Alpine 3900, or H700, or a Rockford EPX, etc) which would also gain you better sound quality over the onboard soundcard. And while you can run the PC from your car's stock loom (it's fused at 10 amps), I'd recommend running a dedicated feed (mine also switches on via a relay but that is because of dodgy electrics in my car on the ignition line).

If you are feeling brave you could wire anything up to be a controller, or you could buy switches yourself and make your own from scratch and incorporate the screen into that, rather than have the screen seperate. You could fit a TFT screen and use the main display from MPXPLAY over the limited LCD one. Alternatively you could use a PLED display using the same Hitachi HD44780 controller and hide it behind some smoked perspex for added stealth.

Obviously this is just one method of making a carPC and there are many more. This one is hinged on speed and sound quality, it boots in seconds, changes track instantly and is easilly stealthed for security.

Software Links

MPXPLAY :: http://www.geocities.com/mpxplay/
DOSLFN :: http://www.geocities.com/jadoxa/doslfn/index.html
FreeDOS :: http://www.freedos.org/

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