ATX PSU to bench PSU conversion

I originally posted this on my (essentially defunct) website, but I see enough search engine hits and refer back to it often enough that I’m going to transcribe it here, on my main web platform, with minimal editing:

Modding a PC PSU to a bench PSU

In order to test and run my projects, I need a regulated power supply unit. Now, to buy a lab PSU it might cost several hundred pounds, and even the type that high schools have aren’t cheap. So I’m going to utilise a cheap source of power supplies- PCs- and modify them to suit my purposes.

Materials required:

• ATX PSU (preferably scrounged from an old computer, no need to unnecessarily spend money)
• LED
• 330Ω resistor
• 10Ω, ≥10W resistor
• terminal posts (4mm sockets)
• toggle switch
• heatshrink tubing.

Removing the PSU from the PC

This part’s easy; there are usually 4 screws holding the unit to the ATX case. Unscrew these, and open the case. Trace the cables from the PSU to the motherboard, and disconnect them. It should just then just slide out of it’s compartment and come straight out. Cut the connectors off the cables, leaving about 3 or 4 inches on the connectors for reuse. You now have a PSU ready to mod.

Inside the PSU

Inside the PSU case.

Unscrew the four screws on top of the PSU, holding the case together. This stage is probably the easiest to sort the wiring out, so sort the wires into colours; I had 4 orange wires, 13 black wires, 6 red wires, 5 yellow, and 1 white, 1 purple, 1 blue, 1 grey, and 1 green. You’ll probably get about the same, with possibly a pink replacing a red, or a brown replacing an orange. These are feedback wires, so just make sure they’re always attached to the correct color, and you can safely ignore them. Tape or rubber band each colour together, so they’re easier to deal with later.

The wires sorted into colours.

If it’s an old PSU, unscrew the PCB from the case and clean it off, with a blower brush, canned air or something. Then screw it back in.

Installing the new Hardware.

In a free area of the case (check inside as well, for heatsinks, fan casing, etc), drill holes that will take the terminal posts, the LED indicator, and the power switch. Line them up first by centrepunching the holes, then enlarging them with a drill.

The finished holes

Now insert your components into the correct holes, and you should have (depending on your design) something a little like this:

The face plate

Soldering it all up

Ok, now it’s time to start thinking about those wires again. here are the colours and their purpose:

• Black: 0V (Ground)
• Orange: +3.3V
• Red: +5V
• Yellow: +12V
• White: -5V
• Blue: -12V
• Grey: Power on indicator
• Green: On/off switch
• Purple: Standby indicator

And a picture, for you visual learners out there:

Bear in mind, the 5V (red) supply is the only one that is properly regulated, if you want the others to be also, you’ll have to do that separately. There are ways to do it, but I don’t think it’s necessary for mine yet. On V.2, perhaps.

When you have them all soldered up and heatshrunk, it should look somewhat like this:

Almost ready to put the lid back on

I accidentally cut the wires too short, so I extended them using mains rated wire. This was so I could just use one wire per terminal, and it can still take any high current. You may also notice that I haven’t used all the wires of some colours. I decided that only 4 per terminal was necessary. The two black terminals are for convenience, rather than to use up wire. One black wire went to the switch, another to the two LEDs.

The power resistor

It goes between a black wire and a red wire, and provides a small load for the PSU, if it requires one to stay switched on. Fix it to the PSU case with cable ties, as it can get quite hot and the case acts as a heatsink. You could use a thermal compound for increased heat transfer, but that’s probably unnecessary. Personally I didn’t use one, and just didn’t turn the unit on until the load was connected. You may feel safer having the flexibility that the resistor gives. It’s up to you.

And now you’re done

Now you’re finished, and once the case is on, it should look something like this:

Complete!

Sources

• WikiHow
• Instructables
• Chris Shadwick

© Robert Taylor 2007

So if you don’t want to keep buying batteries for multiple electronics projects, need a constant power source for high-drain applications like electrolysis (my current reason), or whatever- this should solve the problem.

Alternate version- Flickr Upload

Three days of work later, a new and improved version of Alone in the Mist has arrived… I call it, “Still Alone in the Mist.”

My titling ability knows no bounds.

Click on the link to see a larger version.

Still Alone in the Mist

Originally uploaded by Daegurth

Paracord Bracelet

Just a quick post to say that I made a paracord bracelet last night, it was surprisingly fun and easy. Along with everyone else in the world, I used Stormdrane’s tutorial: http://stormdranespbtutorial.blogspot.com/

If you don’t know what a paracord bracelet is, it’s simply a length of parachute cord woven into a wearable band that serves as an emergency supply of strong cordage that can be used in many situations, from wilderness camping to keeping a satellite in working order.

With an Opinel No.7 for size comparison.

I was using relatively narrow cord (I didn’t have any 550 to hand) and a wide buckle, so I was able to easily double up the length of cord stored on the bracelet. I’ve tied it off with a knot rather than melting it as per the instructions so that I have a little extra length to play with if I ever need to reweave it after use.

~Rob
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Now playing: Glee Cast – Alone
via FoxyTunes

Flickr

This is a test post from , a fancy photo sharing thing.

Some Recent Photos

Well, I’m at home on a northern hillside for the christmas holiday, and for once in the UK, we’re getting more than a light smattering of snow. So I have some pretty pictures of all the snow we’re getting:

A view of Clayton Terrace Road, Chopwell, through snow and mist.

It took me many shots and a very wet camera (it was snowing heavily… you just can’t see it well in the pic) to get the exposure and effect I wanted. Quite a bit of Photoshop after that, too.

Fence stump detail.

This seems to have been left behind when the coal railway was dismantled. Not quite as evocative as I wanted, but without using film (expensive!) I’m not sure how I could achieve that.

Upper Derwent Valley

A south-western view towards Consett and Derwent Reservoir. I had to run to get up the hill, out of those woods, and along the path to the right place before the sun disappeared entirely.

A stream in Chopwell Wood.

This was a very difficult shot, as there were large trees and deep icy water preventing me from getting the angles I really wanted.

I’m planning on going out again tomorrow since we had a pretty heavy snowfall for most of today; there are still several places I want to go to before I go back down to Hull.

~Rob

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Now playing: Loreena McKennitt – 02 Bonny Portmore
via FoxyTunes

A Couple of Photos of Hull at Night

A friend and I went out a couple of nights ago to take some pictures of hull at night. We were there about 10:30 till midnight. Here are the three photos that we were after:

The tree in Queen Victoria Square.

CCFE Fusion Research Centre

A couple of weeks ago, I- and 15 others in my university’s physics society- went to CCFE, the Culham Centre for Fusion Energy, located near Abingdon, Oxfordshire. It’s home to the MAST (Mega Ampere Spherical Tokamak) reactor, a UK project on small-scale fusion, and JET (Joint European Torus), currently the world’s largest fusion reactor. It was in a winding-down phase, having finished its campaign of experiments for this year, allowing the engineers and robots to refit it for next year’s campaign.

One of the guides told us that this would be focusing on replicating as closely as possible a small scale version of ITER (International Thermonuclear Experimental Reactor, pronounced eat-er), the vast reactor being built in the south of France that should be the final experimental step before commercial fusion reactors start being built around 2050. This will allow them to have two- once ITER is operational- sets of data from identically fitted reactors, the only variable being size, thereby allowing approximate extrapolation for comparison with other variables affected by size, such as power output, density, temperature gradients, magnetic containment effectiveness, etc. More data points would, of course, be preferable, but as each reactor costs several billion Euros/Pounds/Dollars to build, this seems unlikely to happen any time soon. The next step after ITER should be DEMO, a series of even larger demonstration reactors built in the seven ITER participants- Europe, the US, South Korea, China, Japan, Russia, and India. These should be the first reactors to run commercially, and will be the final stage before commercial deuterium-tritium fusion reactors start being built worldwide in around 2050.

Logo Design

A lot of people are finding this blog by searching for ideas/help on logo design and only finding the post on my PhysSoc logo. So taking a little time out from designing a band logo, I figured I’d help you, rather than just showing you what I’ve already done.

A few basic tips on logo design:

• K.I.S.S. – a logo is simply an immediately recognisable symbol for what it’s representing. Don’t use any complicated pictures.
• Delete every element you can until you’re left with only the necessary bare minimum. It needs to be impactful and busy designs are not.
• Is it equally legible when printed in black and white? Remember that it won’t necessarily be used in full Technicolor all the time.
• Ensure any text is easily readable, even in a hurry from a distance. It’s all about sticking in peoples’ mind.
• Pay attention to typefaces- what kind of impression are you trying to give? If you’re more about heritage or tradition (or trying to imply such) then you might want a serif font like Times New Roman. Modernity is generally implicated with clean, sans-serif fonts. For my final design on the HUPS logo, I used both Verdana and DejaVuSans extra light. Different font weights provide contrast which is attention-grabbing.
• Don’t feel the need to be too literal with logos; if you look at the contact sheet below, you can see I went from literal at the top with my concepts of physics- quantum and classical mostly, with the particles and apples- to more abstract as I removed the elements that were congesting the pieces and ended up with ideas that are much more recognisable (I’ve seen a group of people in hoodies with this logo on, it’s very effective).
• Don’t feel as though you must include a graphic in your logo- many very effective logos (Twitter, Facebook, and many more) are text-only, as it’s so easy to remember. Unfortunately, they can also be difficult to design- you need to really step your game up when doing text-only, as these websites show: The Logo Factory, LogoMoose Blog. You must generally invent a new font in order to make the word that much more unique and recognisable in context.
• Carefully consider the potential uses of your logo- monitors, leaflets, and billboards all have different strengths and weaknesses in terms of legibility of things like serifs, drop shadows, and gradients. If in doubt, leave it out. In logo design, less is almost always more.
• If you’re using photoshop, don’t go overboard with the filters- we can all recognise glowing edges and lens flares, they’re not interesting. (Yes, I know I have a lens flare in the HUPS contact sheet, but that particular design wes never intended to be taken seriously.)

Now running Windows 7…

Well, it took all afternoon to format, partition and install the new hard drive, convert the downloaded files to an .iso for burning, burn it to DVD, which for some reason didn’t work so I used the very handy Windows 7 USB/DVD tool to mount the image on an 8GB flash drive, whereupon I could finally install Windows 7 Professional. And what a joy it is. Fast, sleek, and feature-rich compared to my old Vista Business installation- although at least some of that can be attributed to my upgrade from the corrupt Samsung 160GB 5400rpm drive to the shiny new Western Digital Scorpio 320GB 7200rpm drive. I’ve only been using it a couple of hours or so, so I can’t judge too much… For now, I’m highly entertained by the handwriting equation maker, and seeing the extent of what it can recognise and decipher. I’m going to explore Media Centre and its ability to communicate with my  Xbox 360 downstairs shortly… Streaming video and music makes my life much easier, no more dual-screening with the TV. The networking seems much quicker and more confident than Vista’s did.

In general, then, definitely a big positive step for Microsoft from what i’ve seen and read so far. Can’t wait to live with it a little, see what’s what. Nevertheless, while I may be a confirmed Microsoft man, I’m not going to entirely sign over my computer to them again; I’m going to install Linux Mandriva on the second partition.

Now, I’m going  to do a little more exploring before bed.

~Rob
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Now playing: Amon Amarth – Cry of the Black Birds
via FoxyTunes

Verizon Droid

Really, Verizon? Really?

You honestly, hand-on-heart, look at your new rebranded Motorola Sholes with the Android 2 OS and see an iPhone competitor? Now don’t get me wrong, I can’t stand the iPhone either, but if you’re targeting the iPhone demographic- sixteen to thirty-somethings who value convenience, ease-of-use and style over freedom, power and versatility- then rebranding the Sholes was entirely the wrong way to go about it. I know retro is apparently cool, but Motorola have managed to find the exact shade of grey, squareness of buttons, and gold trim so that it looks like a cheap calculator from the 80s. I mean, gold? Seriously? I was all ready to believe the hype and celebrate the dawn of a potential iPhone killer (I have no illusions that my beloved Nokia n900 will be one ), but alas, I was misguided and foolish.

It’s not only the styling that damages the Droid’s chances. Having seen pictures of the Android 2 (codename “Éclair”) OS, I’m torn. I’m disappointed by its lack of imagination- if people want the iPhone OS, they’ll buy the iPhone. But on the other hand, you could argue that the iPhone’s functionality and accessibility combined with Android’s relative openness and freedom is a thing of beauty. However, the problem comes when you consider that most people who want the former already have iPhones, or will get iPhones due to the depth of the device’s market penetration- they’ve tried their friends’ iPhones, they’ve seen the adverts, they know that there are at least six times as many apps- the clincher in many circumstances- for the iPhone as for Android. On the other end of the scale, there are the people who want power and the freedom to use it as they will- but Android doesn’t exactly have the best track record of complete freedom, hence the existence of the rooting (jailbreaking for Android) community.

So in the end, the Droid seems to be left in something of a no-man’s land. It doesn’t quite cater to the people it most wants to, but neither is it enough for the people it seems theoretically more suited to. Is this the end for the Droid, before it’s even begun? I don’t think so; there is a median demographic, one that values a good quality UI, but doesn’t place quite as much emphasis on style. They want a modicum of freedom to customise, but don’t want to be in over their heads. They are the average people, non-technical, perhaps believing that the iPhone is as good as Apple claim yet uninterested in their draconian practices, so looking for alternatives. Maybe they specifically want something more like a Palm, HTC, Nokia or Blackberry- which I consider to be the Droid’s real competitors- but want more power and streamlining, and if Gauss is to be believed, there are many more of them than there are of either iFanatics or freedom fighters. The Droid could be looking forward to a bright future- but as a feature-laden powerhouse, the Android equivalent of the Maemo-powered n900 tablet, and not as a direct iPhone alternative.

Promotional Page: http://phones.verizonwireless.com/motorola/droid/

Droid Pictures: http://phandroid.com/2009/10/22/motorola-droid-specs-pics-features-at-motorola-com/

Android 2.0 Pictures: http://www.boygeniusreport.com/2009/10/16/android-2-0-screenshot-walkthrough/

Nov. 6th edit: Droid Hands-on Review: http://ptech.allthingsd.com/20091104/motorolas-droid-is-smart-success-for-verizon-users/