The ATX benchtop powersupply

This summer, I was out playing with model rockets when one particularly powerful one built by my bother managed to clear a quarter mile in range. The rocket even flew up high enough to get lost in the cloud layer. This rocket had enough power to carry a payload, and I really saw no reason why such a rocket should be allowed to fly such an extravagant flight without bringing back a story. bench top power supply So therefore, I wanted to return some data to see how its flight went. Also, I wanted to return some pictures from way high in the air. All of these things I want to do because it’d be really, really cool. Carrying out this project requires a certain amount of prototyping equipment that I didn’t entirely possess. I needed some kind of power supply to test with. So I built one.

Here it is: a few hours at a time over a few weeks yielded me a bench top power supply which is, in reality, an ATX computer power supply converted for prototyping use.

How I Did It:

I had acquired an old power supply at school from someone who was getting rid of their old desktop. To my delight, it was made by Sparkle, my favorite manufacturer of PS units and had dual 12v rails just to seal the deal. In short, what I did was to redirect each voltage rail from the pigtails to a banana jack mounted into the cover of the supply. It wasn’t quite that simple in practice, however. Here’s a more detailed description:

  • First I cut into the pigtails and separated the rails by voltage
  • I cut and drilled and filed out holes in the cover of the power supply, after having carefully planning the holes to not interfere with the internals of the supply.
  • I researched, purchased, received and implanted the banana jacks into the cover of the supply
  • Next the control wire ‘power on’ were soldered to a rocker switch I had sitting around and the ‘power good’ wire soldered to an LED.
  • After that, I soldered two wires of the correct voltage to each banana jack and two ground wires to each black jack.
  • It was basically done at this point. I did some cleaning and inspection at this point. I packed the power supply back up and prepared to test it.
  • I say “prepared” to test because I’ve had a history of making electronics smolder/burn/supernova on me before. So I had a fire extinguisher handy. It check out OK though and the voltages remained spot on under load.

Here’s a list of the output voltages:

  • -12.0v
  • -5.0v
  • +3.3v
  • +5.0
  • +12.0v

In addition, the LED will indicate if the voltages drop out of an acceptable range, alerting me to a problem/short/impending doom.

2m/7cm Cleansweep Yagi

Back while I was at Clarkson messing around with the guys at K2CC, I wanted to build an antenna to work the amateur satellites. I didn’t really have any money at the time, so I literally built it out of stuff I found in the trash.

The Cleansweep Yagi

The Cleansweep Yagi

K2CC’s trash, to be sure, was no normal trash. I had worked the project down to three basic materials, I needed feed lines, metallic rods for the antenna elements, and some type of mast to mount it all in. Well, it just so happened that K2CC was throwing away some short coax lengths, a broken old cubical-quad antenna, and a vacuum cleaner. What do these things all have in common? Enough parts to build an arrow antenna. So I did.

With work, I was able to straighten the elements of the old antenna into rods, much to the chagrin of the guy who threw away the old antenna. I drilled into the hose pipe of the vacuum cleaner and repurposed it as the mast. I used the coax for feed line, no modification necessary. This project took several months, mainly because I had no idea what I was doing. I shimmed the elements into the pipe with toothpicks and glued them with epoxy I found in the basement. I think I spent a total of $2.25 on this project for some copper bits to solder to, but other than that, it’s completely recycled. I kept the vacuum cleaner floor attachment for the end so that I could point it at people and suck up their signal.