This is yet another Diy Bench Power Supply, It's made with an old atx computer power supply from an obsolete HP. It is design to be press fitted to the front of the power supply. I was inspired to build this Bench Power Supply because I needed something to power and test projects, But couldn't justify spending $100+ for a basic power supply which I had the materials and skills at hand to build, So I thought why let a perfectly good computer power supply go to waste and this was born! Some basic soldering skills are required for this instructable, most people should be able to do this as long as you have a soldering iron, even a crappy one. Although one of the not so basic tools that this requires is a 3D Printer, maybe you can borrow a mates or use wood instead. Autodesk 123D is the CAD software I used to design this. If you want me to upload the design files just let me know. This is my first 'ible All feed back is appreciated :) I would love to hear any suggestions on how I could improve it and would love to see anyones attempt at making this.
Step 1: Bill of Materials
The only things I actually had to pay for were binding posts and Plastic for the 3D Printer (Nom Nom) But this is everything you need to build this. Assuming you have all the tools and an old power supply, It won't cost more than a few dollar dollar bills.
- Soldering Iron
- 3D Printer
- Wire Stripper [Optional]
- Long Nose Pliers
- Multimeter (For Testing)
Parts and Sundries:
- Binding Posts (5)
- Toggle Switch (1)
- Rocker Switch (1) [Optional]
- LEDs (2)
- Load Resistor ~35Ω 10W (1) [Optional]
- Old ATX Power Supply (1)
- Plastic (~96g)
- Heat Shrink [Optional] *You can NEVER have enough of this!*
*Side note: I hate bullet points, Just look how stupid they are just being in random places Grrrrrr.*
Step 2: 3D Printing
I tried putting the STLs on here but it kept crashing Chrome so the first thing you'll need to do is download my stl files from Here. Then open Makerware, Replicator G or any software of your choosing, Put the files into makerware and let them process. I just left the layer height at standard as it was a good medium between speed and quality. The 3D printer I used was The Makerbot Replicator 2 and the settings that I found to work best were:
Number of Shells: 3
Layer Height: 0.20mm
I left all the other settings such as temperature and speed at their default setting. These were what I personally found to work best, But if you have arrangements that work better please do let me know so I can share them. I found that the corner tend to lift, So helper disks wouldn't go astray. The complete weight of the printed pieces is about 96g. Assuming you buy a 1kg spool for $30, if we do the math it's not that expensive to print:
$30 / 1000g = $0.03 $0.03 * 96 = $2.88
Step 3: Assemble Printed Parts
Once you have the two necessary parts printed what you need to do is put them together. I made it as straight forward as possible. All you really need to do is put a drop of Super Glue in the holes on the back of the front panel, the holes are shown with the black arrows in the diagram. Then you push the body and front together, Making sure that the pins are aligned with the holes. I appologise for the lack of photos. I have all the parts of the two pieces labeled in the diagrams.
Step 4: Component Insertion and PSU Preparation
Yet again this one is pretty straight forward. You should probably start by pushing the LEDs into their holes. Put the toggle switch through and tighten the nut, I used a SPDT switch. Then you insert the binding posts and tighten their nuts as well, I don't have them in the photo as they hadn't arrived yet. Theres not much more that can be said about component insertion, So we'll move on to prepping the power supply. Firstly you'll want to grab your dremel with a cutting disk attached. We need this to make the cable opening a bit wider. When your doing this you want to make sure that you're not cutting through anything important. Once you have that done we can snip of the connectors. Then we group the wires by colour. We only need 2 wires per colour. So we cut all but 2 of every colour except black, We need 5 black (2 for the LEDs and 1 for the switch.) Now we can cut the wires to length we want, don't cut them to short. You can cover the unused wires with heat shrink or electrical tape.
Step 5: Soldering
Before we begin this step I must tell you not to touch the tip of the soldering Iron. Common sense applies here. I'm not going to go into depth on how to solder as there are plenty of other instructables showing good techniques.I'll start by saying what is each coloured wire is.
- Yellow: +12v
- Red: +5v
- Orange: +3.3v
- Blue: -12v
- Purple: +5vsb (Standby)
- Black: Gnd (Ground)
- Green: PWR_ON (Turns on power supply when pulled to ground)
- Gray: PWR_OK (Pulls high when power is within spec)
I brought 2 Wires of the corresponding colour to the binding posts. 2 Yellow to to the first, 2 Red to the second... Etc. I didn't bother soldering anything to the mains isolation rocker switch.
Step 6: Final Assembly and Testing
The end is in sight. Now that we have everything wired up and soldered we can put it together. It's as simple as pushing the front panel onto the power supply. I designed it so it just about fits, So this requires a bit of force! I also design in screw holes if it's not tight enough for you. Now all that's left to do now is testing it. Grab your multimeter and lets go. Firstly put the negative (black) mulitmeter probe in the Gnd binding post, Then go through all the voltages in turn making sure they are within 5% of what they should be. I think thats everything, Let me know if I forgot anything. I hope if you guys do decide to build this that you have as much fun and learn as much as I did.