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ATX power supply breakout kit.
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ATX power supply breakout kit.

by reportingsjr on Wed Mar 02, 2011 12:57 am

I had an idea a while back to make a small breakout kit for atx power supplies (standard computer power supplies) and was wondering if anyone here thought it was a good idea to continue with. I know a couple of places sell these online (sparkfun and a few small web stores), but they tend to be of low quality (the sparkfun one has no load resistors, no power switch, etc) and figured I would go ahead with it still.

The idea is to have a small laser cut (the hackerspace I am a member of has a lasercutter which I can use cheapely) wooden box with a 24-pin atx connector in the back. On top there will be a power switch and an LED above that to indicate if the power is on. Next to the switch there will be two rows of banana posts. One will be grounds and the other will be one of each voltage (3.3, 5, -5, and 12v). The two rows will be spaced .75" apart for standard double banana jack posts.

This allows you to use any atx power supply you want without having to clip off the connector and ruin the psu for any other uses, and means you don't have to deal with having to know which wire is which. It also includes load resistors so when you are pulling high amps the voltages will not drift.

One of the things I was wondering about was whether or not it's professional to have this all wired up inside of the box, instead of using a pcb. To pull high amps through pcb traces they have to be pretty large, which makes that not so feasible. Can I just solder wires directly from the connector to the banana posts, resistors, and switches? The only things that would actually be on the PCB would be the two power resistors, since everything else is mounted on the case. NOTE: I'm not planning on selling this as a kit since it's so small and simple, but people will be able to see inside due to vent holes and possibly opening up the case. I will open source the schematics. They are dead simple anyways though, haha.

I am planning on selling this all together for about $10-15.

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Re: ATX power supply breakout kit.

by richms on Wed Mar 02, 2011 1:55 am

Would probably crimp some ring terminals on for the banana sockets. I have never had good luck with soldering to the things.

IMO include USB outlets on the 5v as well since thats so useful for running things, you could use the same resisitors Limor used on the mintyboost so that fussy iDevices would charge as well - since you have a PCB after all.

And I dont think wood is the best idea for a case for this being that you have power resistors inside it.

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Re: ATX power supply breakout kit.

by adafruit on Wed Mar 02, 2011 9:33 am

good suggestions, we would like to see a good kit solution to the 'problem' of using ATX power supplies so post up when you've got a prototype!

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Re: ATX power supply breakout kit.

by reportingsjr on Mon Jun 06, 2011 2:30 pm

I was waiting on the local hackerspace I am a member of (hive13) to get a laser cutter. It arrived on Thursday and I got a few prototypes made! :) I still have a few adjustments to make, but I think I am almost there.
Here are a few quick pictures of it (sorry about the blurriness):
http://i.imgur.com/b4V2X.jpg
http://i.imgur.com/CLLn4.jpg
http://i.imgur.com/T3q6B.jpg

This isn't full assembled, as you can see by the wire holding it together. I'm going to add some vents on the sides of the box, move the binding post labels, and add a logo to the front of the box, but other than that I think it's in the final form. One of the things I was wondering about was that since it's laser cut there is discoloration around the edges. Should I worry about that detracting from the overall look of it and sand each one before assembling, or do you guys think it's fine to leave as is?

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Re: ATX power supply breakout kit.

by TheFallen on Tue Jun 07, 2011 8:14 pm

I'd make it twice as big both length and width to space those binding posts out. Definitely DON'T want to have shorts between them, especially on a 600Watt PSU.

As for the laser cut edges, they look fine on my Makerbot Cupcake, they look okay in your (slightly blurry) pictures. Assuming it's really easy to disassemble people can paint/stain/sand to their hearts content. I'd see about laser etching a catchy product name, a catchy manufacturer/hackerspace name, and the OSHW logo onto a side. Although I'd do it so if it was a bit too much you could reverse that side so it's facing into the interior to hide it.
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Re: ATX power supply breakout kit.

by reportingsjr on Wed Jun 08, 2011 12:34 am

Yeah, I'm already working on making it a decent amount longer so there is more room inbetween the posts. I'm not spreading the red/black pairs apart further though, as they are spaced for 3/4" banana plugs. I am also trying to figure out the logistics of putting the text on the reverse side so it doesn't look as burned.

I think the name will just be ATX Box. Short and sweet.

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Re: ATX power supply breakout kit.

by pstemari on Sat Jul 09, 2011 5:23 pm

One thing to consider is adding current sense resistors. Unfortunately the most cost effective ones are all SMD, but pretty big so not as much of a problem.

The biggest headache I found when looking at doing this was that the - side supplies from an ATX box are much, much smalller than the + side. Something OTOO of .5 amp IIRC.
Last edited by pstemari on Mon Jul 18, 2011 2:51 am, edited 1 time in total.
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Re: ATX power supply breakout kit.

by reportingsjr on Sat Jul 23, 2011 8:23 pm

I am finally done designing the atx box and I am almost ready to start selling them! I made the box much larger this time around and added some vents. Here is a comparison with the original size that I posted above (the bottom box is the final prototype: Image.

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Re: ATX power supply breakout kit.

by reportingsjr on Mon Aug 29, 2011 8:44 pm

Completely finished now! I may have some additions in the future, but I'll see if this even sells at first. I priced it $5 above sparkfun's similar kit which is a bit below the 2.3x adafruit recommends. How do you guys recommend spreading the word about this? I am selling it on a site with one other kit, but the other kit is only being sold through the makershed for the time being so there are zero sales on the website.

Final product:
http://www.gfxhax.com/cart/index.php?ma ... ducts_id=7

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Re: ATX power supply breakout kit.

by brucef on Mon Aug 29, 2011 11:59 pm

Site looks good to me and the product is well explained, but I couldn't figure out the shipping estimator exactly.

If I ship to my Beverly Hills address (heh, likely) and I want to minimize shipping costs, is that $8.67 for USPS Parcel Post + $5.00 'Zone rate', or am I misunderstanding that? When I estimate shipping to Canada it looks like the cheapest shipping is $19.40 UPS + $12.00 'Zone rate', or $31.40 shipping on a $20 item.

Ignoring the exact shipping costs in my examples, it would be good to know if that 'zone rate' is an option by itself or an additional charge on top of one of the other listed shipping rates.
- Bruce

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Re: ATX power supply breakout kit.

by lyndon on Tue Aug 30, 2011 11:31 am

If I may offer a few suggestions.

1) Just quote a fixed shipping price to the US, maybe another one for Canada and have rest of world email you for shipping prices. It's easier both on you and your customers. USPS flat rate shipping is CHEAP!! And don't forget you have to pay for the box it comes in, the tape you use to seal it, the label paper, your time in packing it up, etc. "Hidden" costs add up.

2) Mention something about it being laser cut. If I didn't know this, those burn marks around the edges would turn me off because it looks like something is wrong with the enclosure. BTW, why didn't you use a standard enclosure?

3) Nice price for hobbyists. Now add a new version at about 3x the cost for industrial users. But use a plastic desktop case. Seriously, a lot of small electronics companies labs would buy this and not think twice about paying $60 for it. There have been times when I needed to work with a board-level product in my cube, and had to use a huge 1kW power supply simply because we have them in stock, even though I barely needed 5W.

4) If you do (3), then offer a nice, high quality AT power supply with at least a 30% markup for those people. A lot of industrial users won't have a power supply handy and it can be cheaper for them to just buy it from you than spend an hour tracking one down in the office or buying it someplace else.

5) Remember that hobbyists often underprice their products :-)

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