PC  to 12V .CAR2PC

Since some moths, on SORGONET.COM we are working to connect a PC mainboard with 12V, without expensive voltage adaptors that you can buy. Trying to accomplish an easy schematic and using the components to recycle. The use for this system is easy to guess, it could be a power supply for a MP3 car player , a power suppy for an autonomous robot, etc...

                                                                  CAR2PC

The used components are:

-1 AM7812 .
-1 AM7805.
-1 7805 (to suppy power to the HDD, there is one on a usuall power supply).
- PC power suppy wires (from a de una broken power suppy).
- HDD power wires (from the same power suppy).
- 1 fan (there isn't almost more broken power supply).
- 1 heat sink (we get this piece from a broken HIFI).

MA7805,MA7812

I have tested the sytem on a 386 and a 486 (I didn't ask it, but sure that SORGO don't let me try on a Pentium class computer, the reason is because we only have a few units), and works perfectly. The most difficult was to know which wires that goes to PC mainboard are useless and which not, later the AM7805 gets too hot and the system rebooted, I put on a heat sink and a fan to fix the problem, besides, it doesn't supply enough power to boot the mainboard and the HDD, then I choose to add a low power 7805 for the HDD( the same that we do with the Car CD-ROM).
Now it worked, but to improve the security we add a AM7812, this will prevent a mainboard burn out when connecting it to the car, the car battery could sometimes give voltage higher than 12V for a moment.
 
 
PC conectores cortados

The first step is to cut the connectors, to not get dizzied we'll order them in this way: put the connectors on a way that the black wires are touching and the red wires are at your rigth, now it's time to cut beginning on the left of the first connector.
We cut the first and the second, the third is the target and usually is white or yellow, do not cut it, from the first connector cut the 3 remaining ones, yes, the blacks too, now the second connector, the two blacks DO NOT cut, the third, fourth and fifth YES, the last one (red) NO.
It's over, you have broken the connector, of course it's a joke, sure that it isn't similar to the picture, but that's because I keep some wires to use on other things, but you need the 4 wires left. The yellow or white that you have are to apply +12v, the black wires are ground (masa in spanish) (-12v) and the red to +5v.


 esquema
This schema, is important that you use MA7805 and MA7812, this power regulators have 2 pins and the chassis is the ground (masa) like it's on the picture.
Wrote beside the pins are the letters E and B, so to the chassis goes the -12v to the B goes the +12v and the E is the out, then the ground is the chassis and B is IN and E is OUT, on the schema you can see that the low power 7805 is alone, througth it we don't filtered the high voltage form the car battery, could pass througth the filter changing the yellow wire (IN) to the one that comes from OUT on the MA7812, but I didn't test them, don't know if it could afford the power needed to boot the system. If you don't touch it, it works.


Conectando el sistema Configuro la bios

Well, all is soldered and now I connect it, an important thing, do not uses the 12v AC/DC adaptors that are on the market place, because on the tests that I did , it doesn't give enough pwer, better you use a PC power supply to test it, the yellow wire is 12v and the black is -12v. the monitor evidently works with 220v X-), but the keyboard, the video card and the HDD works perfectly with the thing we just make.

 
Conectamos un disco      7805
We could see here a detail picture of the 7805 connected to a HDD, if you connect it backwards, hehehe, you'll have more components to recycle.

Vaya ahora Windows!!

As you could see, the system works, even with Microsoft Windows, that's the hardest test that we could try on a system
The system is easy, we hope that the electronic engineers out of there that are reading this web page gives us a hand. We're sure that with a capacitor here and a resitor there indeed we could get better results, but I don't know where to put it.

A final advert: Not even Me nor SORGONET.COM hold the responsibility, if you try it and you break your system, and if you connect wrong a wire surely you will crash the system. Be carefull.
by Necro_
www.sorgonet.com


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