As a hobbyist and tinkerer, I am constantly in need of low voltage DC. Primarily 5V and 12V. Instead of spending money for a variable power supply (which are nice and I would absolutely love to have one) I decided to make one myself. I chose to utilize a computer power supply unit as the power source and I am certainly not the first to do this.

However, Instead of butchering the computer power supply, I built a simple connector that turns it into what I need. I used a small rectangular project box, a switch, four screw/banana power connectors and the ATX power connector off of a dead motherboard I was throwing away to make the project.

Here are all of the components that I used. I ended up using three of the red power terminals.


Next was to mount all of the components. The Terminals are very easy to mount, just drill four holes. Make sure that you are insulating the terminals, if you use a metal case then you need to think about that. I mounted the ATX connector with hot glue. This was done after I soldered wires onto the voltage pins that I wanted. Here is the pinout for the ATX connector coming from any standard computer power supply.

ATX Pinout

I wanted +12V, +5V, +3.3V, and COM (aka ground). I also soldered a wire to PS_ON which will allow our switch to turn the power supply on and off.

PSU Module

I was afraid that I would need to space the connector due to these feet (the project box is actually upside down) but I ended up not having to.

PSU Module connector

I am out of labels and also lazy so I just scratched the voltage into the plastic below each terminal. Function / Form.

PSU Module Banana Plugs

My power supply has a switch on it so I ended up not even mounting the switch I was going to use. I tied the above PS_ON wire directly to ground with a large loop of wire. This will instantly turn the power supply and there is enough slack that I can come back later and add a switch if I would like to.

PSU Module Connected

The power supply I am using has a 24 pin connector but I just let the extra pins hang off.

24 Pin Compatibility

After testing with my multimeter I am very pleased with the result. This is very compact and extremely useful. I can add terminals for additional voltages if I never need them.

Installed PSU Module

This was a very simple project that only cost a few dollars to complete. If this power supply ever dies, I can just switch it out for another one. My power supply also has removable cables which keeps my desk clear and clean. I can also re-connect those cables to have as many Molex, SATA, and other power connectors as I need.