Introduction: How to Turn Your Old PC Power Into a Lab Generator

By Cyroul.com
About: Web raider since 1995. Blogger on cyroul.com and tweeter with @cyroultwit

Nota : Excuse my English. I do not often write in the language of Shakespeare, so I think I'll make lots of mistakes.

I am for too long a badger which knows how to align lines of code, but is dumb to understand electricity ever. Certainly the result of a long educational work of a f* physics teacher who liked to humiliate me in front of the class. Yet electricity is the basis of digital creation. Without electricity and understanding of electricity, no electronics. Whitout electronics, no digital. So, as a challenge to myself, and to revenge this asshole teacher, I decided to immerge myself in a project 100% electric.

The project / equipment

My needs were simple, but difficult to found in a store for less than an hundred $. Here's the list:

  • I needed a +5 V output for my Arduino's projects
  • I needed a fan facing my head for when I solder at my desk
  • 4 outputs GND / +3 V / +5 V / +12 V and all ths voltages that can give me the power supply
  • And all this in a small volume (I have not much room on my desk)

The material used will actually cost me about € 5 (without the coffee) :

  • an old ATX PC power supply, the big box with a fan which converts the 220 V sector into usable power the motherboard and other components of your PC.
  • one or two switches (directly from your box crap)
  • some banana plugs females (have to buy it - it's a little expensive)
  • 2 LEDs and 2 resistors that go with it (aim 330 ohms - I did not have in stock, I took my 500 and LED light winded)
  • possibly for very very old models of power supply, you need a power resistor (10 ohms - 10W). Luckily, I did not need.
  • You will get back the wires on the power supply.
  • A soldering iron, solder, wire cutters, and hot glue.
  • A multimeter for testing.

Ready ? Go !

Step 1: The Power Supply

In most cases the power supply have on one of its sides a label with the different voltages it distributes and the different colors of the wires. Keep well this label, it will save you lots of time.

In case you do not have this label, you will find references to your diet (at a site like pinouts.ru for example). If you do not find it, it will be the multimeter hand. Most colors are standard, but it is better to test.

Warning! Achtung! Danger !

The two large cylinders that you see at the bottom of the picture are high voltage capacitors. If they are full and they discharge through you, you will feel it hard. So be careful (unload and do not touch the cylinder). The house is not responsible for your horrible death in atroce agony.

Step 2: Pruning Some Wires

First step, remove the wires which are useless. Do not discard them! Wires are always helpful. Cut at the base. And after testing, if everything works, you insulate all the bases with a shot of hot glue.

Once the cutting is complete, it's time to test if it's working.

Step 3: The Test Voltages

PC power supplies run only if it is requested. For the test, you have to create a connexion between a GND wire (mostly black) and the PGwire -Power Good- (gray color for me). This will allow you to turn on the generator that otherwise would not work.

You can add an LED to your switch. It will be more visual.

You can also use the PS-ON wire (green for me) to turn on a "standby" LED. I did not but it is possible. Remember in this case the resistance of 330 ohms (otherwise your LED will burn).

Does it work? Great, now will have to put it in the box and solder.

Step 4: The Design and Welding

First of all, when you build a project, it's better to make a plan-design-pattern of your final object. It allows you to be clear about your current outputs and location of the various elements and then it can give you aesthetic ideas.

My diagram is on the image. Obviously, the end result will be a little different from reality (without measurements improvisation is always interesting).

One day I will have a real workshop to me with a machine tool to manufacture beautiful metal housings and put my creation. This is not the case yet, so I chose an old blue box Playmobil of my daugther, dragging since last Christmas and a cutter for cutting. Upcycling I tell you.

Cutting did, wires welded, I found in my scrap box (you should always have a scrap box at home) an old broken USB lamp Made in China (the sort of gift people give you when they don't know what to offer and they know that you are working behind a computer).

The lamp was not working, but only the USB part was dead. I was able to recover the long flexible neck to give a strange touch to the generator.

It was finally the most difficult step: welding the microscopic wires of the USB lamp switch and a big recycled (I had more than 330 ohms). Hard part.

Step 5: Enjoy the Results!

So I'm very proud of this beautiful strange object that now fits perfectly with my messy desk. I still have to paint it and add elements of decoration, but we will see later.

In conclusion, this project allows me to learn about electricity, without endangering myself too, and with the profit of converting an old and useless power supply in generator that allows me to play with Arduino. So if you have a few hours to fulfill, do not hesitate and have fun!

You can find generateur de PC en alimentation de bureau, and you'll also find plenty a lot of tutos on this subject,. Here's some of the most useful (in french):