

Turn an ATX Power Supply into a Bench Power Supply - coderdude
http://jaygoel.com/projects/powersupply/

======
memset
Hi all, I made this! Neat to have my dream of being on the front page of HN
come to fruition.

To use HN parlance, one might say that I have launched! (Any VCs out there
want to discuss other ideas I'm working on?)

This kit look me about 6 months to put together, from prototyping the PCB to
iterating over an enclosure design. Waiting for components to arrive in the
mail (PCBs, laser-cut designs, resistors) was what took the most amount of
time.

When I started, I was fully convinced that I would have a working product
within just one or two iterations. Putting together a polished hardware kit
(and I'd say that this has some degree of "polish" to it, though far from
perfect) is much more difficult and time-consuming than I would have ever
imagined. Quite different from the agile! lean! iterate! that we talk about in
software-land.

Oh. So I have 4 or 5 PCBs from the first few iterations. If you end up
ordering one (and I encourage you to do so!) then send me an email and I can
throw one in the box. You know, as a collector's item.

If you have any questions or anything, do let me know. Be on the lookout for a
post describing some numbers behind this traffic spike.

~~~
coderdude
I think the SVG box generator script that you wrote is a neat by-product of
your production.

<https://github.com/poundifdef/SVG-Box-Generator>

~~~
memset
If you're interested, there are two things I've been meaning to update about
this script (I promise I will merge your pull request!)

1\. The measurements do not take the laser's kerf into account. That is to
say, it does not account for the thickness of material burned away by the
laser, so the resulting faces are a bit loose.

2\. If you look at the design, the tabs (where the faces fit into each other)
go straight across. It would be better if the tabs were smaller, and then have
several of them fit together across the length of the box, rather than one
long tab.

------
mrmekon
While this is fine for the home tinkerer, an ATX power supply doesn't provide
any of the basic safety features that are one of the main points of a
professional lab power supply: protection against over-voltage and over-
current. You really don't want your power supply to be damaged by a faulty
circuit. And who knows how clean the power is.

Most people who have a use for a bench supply should also be able to figure
out how to make this box for $2 instead of $45.

~~~
fr0sty
Can you make a power supply recommendation for the casual hobbyist?

Edit: I mean a variable voltage variable current bench/lab power supply.

~~~
r0s
For the voltages here any used ATX power supply will work.

Instead of this box you could just clip the appropriate wires for the same
effect.

What I really want is a variable voltage supply easily made from any old ATX
PSU. As an amateur that would be an invaluable tool.

~~~
memset
One gentleman has done a writeup on creating a variable supply from an ATX.

[http://hackaday.com/2010/12/09/atx-psu-turned-into-an-
adjust...](http://hackaday.com/2010/12/09/atx-psu-turned-into-an-adjustable-
voltage-bench-supply/)

It might be a good starting point for a kit which doesn't require a
modification of the power supply itself.

------
jevinskie
Hey memset,

I bought the fully assembled product because I felt the kit version was
significantly overpriced compared to the bare PCB and the $5 savings was not
worth having to assemble it myself. I hope you're making a good margin on it!
:) Regarding comments from others about the possibility of poorly regulated
PSUs: you are absolutely correct! I verify the performance of the (higher
quality) PSUs that I use before I hook them up to my projects. I've already
created an integrated version of this that has worked wonderfully and I am
excited for this more versatile solution. [0] Still, when I need a verified
good, current controlled bench supply I use a 40+ lb (18 kg) HP bench supply.

[0]:
[https://picasaweb.google.com/100509155963341533738/BenchSupp...](https://picasaweb.google.com/100509155963341533738/BenchSupply#5217516826120840482)

~~~
memset
I just received your order. Thank you!

The margins on this are not bad, but I wouldn't say they are stellar either
(for some definition of "stellar") You can look at all of the
components/PCB/acrylic and back-of-the-napkin estimate its unit cost, not to
mention shipping+assembly (hand crafted!)

You raise a good point in terms of the non-assembled version only being $5
cheaper, which is further confused by not wanting to undercut distributors'
(okay, one distributor thus far) prices.

It's interesting, because I've never really had to worry about _these_ kinds
of issues (pricing, distributors, expensive unit costs) in the past; it is
kinda fun to look at a project from these other angles, orthogonal to the pure
engineering component!

------
pingswept
This thing looks great.

I love the trend of people making well-documented kits that I have a good
chance of fixing if they break. I'll have to scrounge up an old ATX supply-- I
think I just threw my last old one away a few months ago.

~~~
memset
Thanks so much!

The documentation took a _long_ time. I went from no documentation, to a 30
megabyte PDF I created with OpenOffice (not recommended), to borrowing a
friend's light box and buying InDesign to create a pretty neat assembly guide.

Incidentally, the Adobe Suite might be the first proprietary software I have
ever purchased (well, besides an occasional video game.) I have not regretted
the purchase and it runs well enough for my purposes on a VM.

<salespitchmode>You never know when an old ATX supply will come your way, or
when you'll get the urge to work on a neat electronics project. Better to have
the tools on hand, order today!</salespitchmode>

~~~
pingswept
The photos are great-- I think the lightbox was worth it.

I'm not sure about InDesign. Wouldn't it have been pretty easy to make a web
page that had roughly the same appearance as the PDF?

~~~
memset
This is true. I wanted the flexibility to attach PDFs, print them out, let
people save them to their computers, change my URL, etc - without breaking
anything. Plus, it is much easier for me to update the document via a GUI
rather than trawling through HTML+imagemagick just to resize an image or
something.

But it is a good point; I may change this in the future?

------
chopsueyar
Make sure the ATX power supply is actually outputting 5v and 12v first!

------
Sauce1971
I use a poweradaptor from a dead external disk. They output a steady 5v and
10-12v. Just cut the cable and add some banana clips. Great for powering a
breadboard for a hobbyist.

