A long time ago in a galaxy far, far away... I converted a 300W ATX power supply into a multi purpose power supply. In addition, I decorated it based upon the Galactic Empire from Star Wars. The "multi purpose" quality was dancing in my brain, and I decided to get the following:
- 12V, 5V, 3.3V, -5V, -12V and 0V outputs. These are the stable voltages that offers the ATX power supply. Yes, I considerated to add a variable voltage output, but I finally decided that it was much work for a little utility (for me). I want to get stable voltages but, if I would want variable ones, these would be made in my external circuits. Moreover, you can combine these voltages and get theoric 7V, 8.7V, 1.7V, 10V, etc, so you have a plethora of stable ones.
- Molex output, with 12V, 5V and two GND.
- Berg output, with the same as above. Ideal for pin cables.
Well, my thoughts are around giving voltage to Arduino, mobile phones, and so on. And finally, it is a very cheap project (less than € 5 if you have the ATX), a constant in my instructables.
Step 1: Gathering Materials
- An ATX power supply. I got one from and old desktop PC, and yes, it had a power switch. If yours have not a switch, you can put one which conmutes the PS-ON wire (green wire) with a GND wire (black ones).
- Female banana plugs. I bought them in Ebay (10 pc for €1.50).
- A female A-type USB. I got one from an old router.
- Wood. Any type will be ok. I used a wooden fruit crate from trash.
- Paper. (and optionally a printer).
- White glue.
- 4 screws.
- Painting (I got a cheap one: around € 1).
- Scissors, screwdriver, drill, saw, brush, tester.
Step 2: Making the Box
Depending upon the size of your ATX, the measures could be different as mine. I used 16 x 9 cm for the front view. The high is about 2 cm higher than the supply in order to give it some ventilation. The large measure should be enough for allocating the power supply and bending the wires.
For the front panel, make 6 holes for the banana outputs. In addition, make the holes for the USB, the Berg, and a Molex. I made all the holes with drill.
Make the remaining pieces of the box, sawing and glueing them. In the front, glue two thin pieces for screwing the front panel.
Step 3: Connecting the Wires
The colors for the different voltages are:
Yellow: +12 VDC; Red: + 5 VDC; Orange: +3,3 VDC; White: -5 VDC; Blue: -12 VDC; Black: 0 VDC (GND).
The 4 pin Molex peripheral Connector gives 12 VDC, 5 VDC and two GND.
The 4 pin Berg Connector gives 12 VDC, 5 VDC and two GND.
For the USB, we only need the 5VDC and GND, discarding the data pins.
IMPORTANT: In order to make the ATX working, you must short-circuit the PS-ON wire with a GND one (green with black). Or, if your ATX hasn´t a switch, put one between them.
Step 4: Final Retouches
I optionally added four wooden frames to the structure, which gives a better appearance and strenghtness. I printed some labels for the front and top panel (pdf file attached) based upon the Galactic Empire of Star Wars (yes, I´m a fan ^_^).
The "Aurebesh" characters mean "Power Supply".
Step 5: Testing
Take the tester and test every output as you can see in the photos. I tested the usb output connecting a phone ^_^. If every connection is OK, congratulations, I am sure that this will be very useful for your projects.
Step 6: Adding a Status LED
I finally decided to add a status LED. I chose a red one and connected it to a 3.3 V output, with a serial resistor. To calculate the resistor I estimated a nominal current of 0.02 A and a drop of 2 V in the LED.
Rmin = (V - VLED) / I = (3.3 - 2) / 0.02 = 1.3 / 0.02 = 65 ohm.
I finally used a commercial 68 ohm resistor. Enjoy and may the Force be with you.