Bench Power Supply from Extra PC Power Supply Unit

This has been a project I should have completed years ago. Finally, I need a clean 12V DC power supply. Digging though my box of unused wall warts I was able to find only one and it was questionable. I gave up and created my own bench power supply from an extra computer power supply unit.

Desktop power supply unit converted to benchtop unit

This is a simple project and will alleviate the hunt for yet another wall wart of a certain voltage. A single converted PSU can easily support multiple Arduinos, Raspberry PIs, Jetson Nanos, cameras and microphones. The result is a single power supply providing cleaner power than a cheap wall wart. The simplest conversion using a computer PSU provides support for 12, 5 and 3.3 volts. With a little more design, the PSU can have LEDs for power, a thermal-controlled fan , reverse voltage and even variable voltage. I stuck with the simple 12, 5, and 3.3 volts configuration.

If you already have a spare PSU laying around, The project parts low cost if you have a spare PSU. I used 3 red and 1 black banana jack post and a hand full of crimp on wire connectors (from the auto parts store). Its very simple to convert the PSU. Black wires and the single green wire (controls on and off from computer) connect to the ground post. Yellow wires connect to the 12 V post. Red wires connect to the 5 V post. Finally Orange wires to the 3.3 V post. The hardest part of the project build is to get the wires short enough to fit into the PSU case. Once complete, power up the converted PSU and test the output voltage with a multimeter.

Image of the inside of converted desktop power supply unit

With this project complete, I now have a single clean power source to power up multiple projects requiring 12V, 5V and 3.3V of clean power. No more hunting down yet another 5V wall wart for another micro board and now the power is stable under load.

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