PC Casemod-inspired Benchtop PSU


[Will] had a cheap power supply sitting around, and decided to turn it into a full-featured benchtop PSU. Inspired by some of the other benchtop supplies we have featured in the past, he decided that he wanted his PSU to be more than just a simple-looking box sitting on his work bench. Taking some cues from PC case modding, he put together a unit that is not only very useful, but also quite sharp looking.

The frame of the case was crafted from aluminum angle, while all of the other flat surfaces were made using black polycarbonate. He installed the standard 12v, 3.3v, and 5v terminals you would expect from any benchtop PSU, complete with an LCD display showing the voltages provided by each rail as measured by an Arduino stationed inside the case. Additionally, he installed a variable terminal capable of providing 1.3v-30v, along with its own LCD display. The most unique feature is the multimeter embedded in the front of the case, which makes it virtually impossible to lose.

The case is finished off as you might expect, if you have seen any of his previous work. It features LED lighting on the inside, large fans on either side of the case for optimal air flow, and a pair of machined aluminum handles.

Be sure to check out the quick video below of the PSU being powered on.

28 thoughts on “PC Casemod-inspired Benchtop PSU

  1. I like the build progress photos. It’s a good look into how he fabricated the case and mounted the components. I’ll be book marking this to ref. for upcoming projects.

  2. There’s a switch to turn the lights off :) I put them in just to make it different from the standard bench-top PSU.

    I’m also going to try in the near future to put a backlight on the multimeter display, as it’s kinda hard to read in anything less than direct lighting.

  3. Agreed, +- 15V rails would be a great addition. At least for us analog guys.

    I might have to submit my PSU. Steps 12VDC up to +/- 3V-55V. :) even regulated. Good ol TL495. Was originally for a class D amp I was building,(so it is capable of outputting a crap load of current.) Only down side is I need a 12V source. Often I use a computer PSU…I know I know, it’s a little pointless stepping up and down a bunch of times.

    But anyways this is an awesome build. Very well executed. It came out quite clean looking too.

  4. @Rick Autry

    I know right? He could have at least added the -12V rail thats part of the ATX PSU pinout. But really though this is a great build, a bit over the top even but that just gives it personality.

    Also no mention of (what looks like) the Molex connectors underneath the multimeter. Definitely would come in handy considering Molex connectors are so easy to come by.

  5. @Myke, it’s 100% useful actually. It’s a lot easier to use than having an ATX PSU on my desk with all it’s wires all over the place, and this way all the voltages are regulated and displayed, so I know exactly what is going into my projects. I got tired of the spider web of wires, or even the spare molex hanging out of my computer case to get power lol. The downside to that is if you accidentally short the wires…then the whole computer shuts off…

    @AdamD, I was thinking of using the -12v rail in combination with the +12v to get the 24v, but the -12v rail on this particular PSU was only 0.3A. The step-up converter I am using for the higher output allows me to pull up to 3A if needed, as it pulls right from the +12v rail.

  6. @Will

    The point of adding the -12V rail wasn’t really to have a larger total voltage swing but rather to have a negative supply in reference to ground. This is useful for analog circuits such as operational amplifiers that are used on AC signals which Rick Autry and Fallen alluded to. The limitation in power output on the negative side of the supply is common on all ATX PSUs but when prototyping analog circuits as I mentioned, 300mA can be more than enough.

    Of course if your not building these kind of circuits I can definitely understand why you didn’t include it. Just that if I built a supply for myself I would have included it. :P

  7. What he needs is a DC-DC Isolated power module for the panel meter. Most digital meters cannot share a ground for their power source and what they measure. A isolated power module is simple little device made for this purpose.

  8. I love it. The only (cosmetic) thing I would add is some good ol’ yellow/black warning stripes ;) Also, I think the two handles are a bit much (although I’m not sure how heavy this sucker is ;)

    If I do something like this, I’ll probably use clear acrylic painted on the inside. Areas left unpainted would allow nice, “dust-inlet-free” status lights, LCDs, etc.

  9. @AdamD, I now see the significance of the -12v line, and I don’t build those types of circuits, which I guess is why I didn’t need to put it in. Although, the -12v line is still accessible, so if I need it in the future I can always wire it up to another banana connector and it’ll be there :)

    @Amos, this sucker probably weighs in around 5 or 6 pounds, so the handles aren’t really needed, but they look sick and make it easier to carry around

  10. Useful, right. You have so much wasted space there, it makes me cringe.
    Also, current limiting? Enjoy your sparks and smoke when you accidentally make a short.

    A triple or quadruple output power supply can be made very easily. With variable voltage regulation and adjustable current limiting.

    Also, switchers deliver way too much noise to the power rails.

  11. @Adam, the male and female Molex plugs under the multimeter and the standard 12v-g-g-5v pinout, so any molex-connected device will function as intended. Also just between the molex’s and the LCD is a 2-pin LED tester, that’s hooked to 5v (with a resistor, of course) and gnd to test LEDs quickly and easily.

    @Myke, as far as wasted space goes, it’s a case-mod inspired unit, so it’s function AND form, not just function. It’s got everything I need and will use, and that’s that :)

    And as far as current-limiting, if something gets shorted the PSU will turn itself off as a normal one does. So all that’s required is to unplug it and plug it back in and it’s good to go again :)

    And I’m not understanding your comment on switchers to the power rails, care to elaborate?

  12. @will he is referring to the fact that a switched power supply doesn’t have a smooth DC output. There is an AC wave riding on the DC rail. To see it, look at the output with a basic 20mhz oscilloscope. Old switched PSUs definitely had the problem, it is less of an issue with modern ATX Supplies, because of the power requirements of the new motherboards. It is still there, just to a lesser degree. If most of what you are doing is small analog projects you probably wont ever run into a problem. If you start working on projects that require you to dig around with a logic probe you may want to invest in a more expensive non-switched regulated supply.

    I do think that you should invest in a set of circuit breakers on your output lines. While ATX supplies are cheap, kicking them off in the way you suggest will cause them to go squirrel-ly long before they fail completely.

  13. @R, thanks for explaining it, that makes a lot more sense now. For now all I’m doing is simple analog circuits, learning microcontrolelrs and such.

    Down the road I’ll probably invest in a real unit, but for now this serves well enough and was fun to make at the same time. I’m going to try a way to work in current measuring at least, and hopefully current limiting into this unit in the future. I’ve got one ATmega doing the voltage measurements and running the LCD, and I may use a second with a second LCD to do the current measuring and/or limiting, but we’ll see what actually happens.

    Once again, thanks for your input, it was very much appreciated, and I’ll try to figure out a way to add some sort of circuit breaker to this as a precaution.

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