Handy Bench Power Supply

Here's a quick and dirty power supply for the bench. I do have a couple lab power supplies but often I just need power to test something quick.

I've posted here before about XBox power supplies – 5V @ 1 amp max and 12 volts at a whopping 14+ amps. And I've also posted about power supply buck or buck/boost modules.

One of the neat features of these XBox power supplies is that the 5 volt is always on, while the 12 volt supply is controllable by a 5 volt signal.

For my bench supply, I laser-cut an acrylic panel
for one of the buck/boost power supply modules, a 12V enable switch and binding posts for 5 volts, 12 volts and the variable voltage/constant current output of the power supply module. This provides fixed 5 volts at one amp, 12 volts at up to 16.5 amps, and variable voltage from 0 - 35 volts at up to 4 amps.

The power supply module was about 5 bucks from one of the Chinese vendors (there are many different versions), and the XBox supply was also about 5 bucks from a local thrift store.

The ulluminated switch is one of the type Radio Shack used to sell, designed for automotive use. It has an internal resistor, set to power the LED at 12 volts, but it's plenty bright operating at 5 volts. Note that the switch only switches a 5 volt logic level to control the 12 volt supply; it does not have to handle to ~16 amp output of the 12 volt supply.

If you say nice things, I'll post the SVG file to laser-cut the panel and a schematic showing the connections.

Forgot to mention, this will be screwed to the shelf over my bench, taking up no room and being easy to read and operate.

Your supply is beautiful. How/where do you make such an attractive faceplate?

Thank you

It's a piece of 3mm laser-cut acrylic, with Brother printer labels (white on black) that blend right in the the glossy panel.

I can't cut a square hole in a panel with a Dremel tool or any other way. A laser-cut panel, assuming you measured correctly, is awesome because everything fits, the cuts are square, the binding posts are in proper holes to prevent spinning and spaced with the proper ¾" center-center distance.

Do you have a laser cutter? Or did you employ an external service?

What CAD software did you employ to generate the SVG file?

I don't have a laser cutter but there's a nearby public library with a maker space that has sessions a few times a week where you can use a laser cutter for free.

I use Microsoft Visio most of the time to generate SVG files but it's not ideal for SVGs. I've also used the board layout section of EasyEDA which does work rather well.

I get most of my material from the cutoff bin at a local plastics supplier.

Here's a more complex project I just finished today. I needed a stand-alone enclosure for a Wake Turbulence Timer normally mounted in a cutout in a panel. Its shape is such that no off-the-shelf enclosure would work very well, and definitely not provide the appearance I wanted.

I created an enclosure using matte-finish acrylic and segments of Lego Technic frames* with brass heat-stake thread inserts to hold the

corners together. Lots of 3mm screws and thread inserts!

Started with this tray of pieces.....



Secured them with the Lego frame pieces....



And this is the result.....










* I posted about Lego Technic frames to create enclosures a while back.

I wish I had half your project building skills!