Posts Tagged ‘PSU’

Universal Wall Wart

Thursday, August 11th, 2011

I finished this project about a month ago, and decided it was time to share with the world. I noticed while I was consolidating my technology that even after getting rid of more than half of what I had, there was still a nasty little problem plaguing my desk… a jungle of cabling, all attached to wall-warts. It had gotten so bad, in fact, that almost an entire UPS was filled with them, plus a few outlets in the second, plus a few on a power strip.

It was ugly, a mess, and impossible to work with. I was constantly unplugging one to plug in another. Today this device needed to be charged, that device was needed for a project or another just for fun. Finally, I decided to do something about it. I got the clever idea to use an old (but only lightly used) ATX power supply. This had a high chance of success, since almost every device had either a 5v or 12v adapter. It didn’t take long either, and it accomplished a few goals:

  1. Cleaner; no more cabling jungle…
    Every device which was using a wall wart is now run from the power supply.
  2. More efficient…
    1. No more vampire-draw (switching power supplies only draw [slightly more than] what is necessary).
    2. More efficient (cheap small switching power supplies typically have lower efficiencies than ATX PSUs).
    3. Expandable (even with all devices running under full load, the ATX PSU has plenty of breathing room for more devices).
Here’s a quick rundown of what this bad boy is powering:
WRT610N Router 12v 2.0a Max
4-to-2 HDMI Matrix 5v 2.0a Max
Creative Extigy Sound Card 12v 1.0a Max
Belkin Multi-TT USB Hub 5v 3.5a Max
PS3 Controllers 5v 1.0a Max

This is a grand total of 68.5w:

  • 12v 3.0a Max (PSU can push 9a)
  • 5v 6.5a Max (PSU can push 20a)
For finishing touches, I added a switch to activate the PSU, an LED to indicate power status, and 2 USB ports scavenged from a PCI bracket motherboard adapter. I used 220 Ohm resistors on the data pins (lets USB devices know they can safely draw 500ma). It was all pretty simple, just some simple wiring, a few solder joints and a little patience. Here are some pictures, enjoy!!!
Here’s a top-view. I used a spare 20-24 pin ATX adapter so I wouldn’t have to cannibalize the PSU. The terminal strip allows easily adding more lines if necessary. I stuck with the color coding of Yellow for 12v, and Red for 5v. The black electrical tape covers the resistors for the USB ports.
Here’s a front-view. I used a nibbler to cut the holes for the USB ports. The switch fit perfectly into one of the holes in the cube. A quick hole was drilled and a panel mount used to secure the power LED.
Here it is finished. I picked up some plugs at Radio Shack to connect the devices (router, HDMI matrix, sound card and hub).

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