ATX Bench Power Supply

As you may have noticed, lately I’ve been learning electronics. My budget is not unlimited and was wiped out by my purchase of a Rigol DS1102E Oscilloscopeover Christmas. I needed a bench power supply of some sort for my experiments and while I’d love a real variable bench power supply I started to think of using a surplus (I have a bunch salvaged from dead PCs) PC ATX power supply as a substitute for the time being.
There are tons of such projects out there on the internet but most involve hacking open the power supply and I didn’t think that was the way to go. I considered getting a cheap ATX adapter from Monoprice and breaking out the voltages onto a PCB but then I came across the Dangerous Prototypes ATX Breakout Board.
It was only $13.80 plus $3.80 shipping from Hong Kong (via Seeed Studio) which was reasonable and quite a time saver. I happened to have an old used project enclosure laying around in my junk pile (I have no idea where I got it from) that would fit an ATX supply so I set to work.

I laid out the ATX mounting profile, chain drilled the outline and chiseled out the waste.

Finally an excuse to use my die filer!

Filing the outline.

The ATX supply mounted to test fit and function.

Just enough room in the project box.

The box didn’t have a front panel so I made one from aluminum. The box had feet on the sides and bottom but I decided that mounting it vertically would be best so I removed the feet on the bottom (now side) of the box)

I had to add a piece of angle in the middle top to support it.

The breakout board mounting laid out. The large holes are for clearance for the binding posts.

Test fitting.

I had considered mounting it flush but decided standoffs would be safer and easier.

A rectangular hole was nibbled out. It’s almost as if I knew how to make square holes in panels…

Remaining wires tucked into place. I can pull one out the side if I need a Molex connection for a project.

In hindsight I should have made the rectangular hole slightly further up as the wires needed to be massaged into the sharp bend. I protected the wires from the hole edges with some spiral wire loom.

Not bad, the board works well, has tiny little power indicator LED lights and this will be a useful bit of equipment for my hobby. If the ATX supply blows up I can just pop in a new one. I’ll need to get a binding post for the –5V as my supply has that voltage (I wish they included it). The only real change I’d make, for my setup is to have the Molex connector come out the bottom of the board – this would have made the assembly much cleaner. Maybe I’ll make my own board someday.

A Few More Pictures From The Corvallis Maker “Festival”

We went back to the 2nd day of the Maker Festival lured by the promise of new exhibits and the fact that the kids forgot to get the disks to the Wii games they checked out of the library the day before. Yes, the library has video games.

The Eugene Makerspace showed off their “Quarktronic” sound machine.

Kinetic Creatures had cardboard automata.

Dawson Station, an Arduino controlled model of the Hull-Oakes sawmill.

The library bought some of these Sparkfun Inventor’s kits but for some reason are only having classes for teenagers. Such rampant ageism.

A rude 3D print. Ok, art print.

All in all I think a slightly larger space with all the exhibitors on both days would have been better, as well as more community involvement and communication. Many people had no idea it was going to happen until the day of the Festival. Also they really need to call it a Maker Faire and ally themselves with the official Maker movement. But that requires 6 months advanced planning apparently.

The big problem with Corvallis (or the Mid-Valley) is that it’s an extremely nerdy area with tens if not hundreds of micro-communities that do not communicate between themselves. We have the OSU Open Source Lab and sundry other OSU clubs and departments, Linn-Benton Community College, Da Vinci Days, Bike Co-op, sustainability nuts, home shop and model engine lunatics, R/C enthusiasts, HAM madmen, a model train club, Hewlett-Freaking-Packard, solar, nuclear and biotech startups, as well as people toiling anonymously on their favorite hobby-horses in basements and garages.

This is partly down to the psychology of the nerd and partly due to the lack of any centralized clearing house for nerd-events and resources in the Mid-Valley. Mostly down to psychology though. A couple of well funded and time-rich motivated individuals could change all that. Clearly I’m not that guy, so I can’t complain too much.

So I’m happy the “festival” happened and exposed people to things they may not have known about (it makes me seem less insane to my friends) and it was fun to have conversations with people doing neat projects.

Maker “Festival” At The Benton County Library

We went to the Maker “Festival” at the Benton County LIbrary (.pdf flyer) today. Not sure why they called it a festival instead of a fair, but that’s Corvallis for you… We stayed for about an hour and a half and we’ll go back tomorrow as there will be different exhibits.

Lonely little robot.

OSU robotics had quadcopters.

The room.

Tiny robot.

One of two Makerbots.

Snap Circuits and K’nex.

Felt fun.

Raspberry Pi, programming lights to blink with Scratch.

Lego robot w/ many features.

Bubble machine.

Some neat boards made by Ken.

A Nice Way To Spend An Afternoon.

I glanced over at the side of the pump house today and noticed that it was dripping water at the bottom of the siding. The faucet pipe wasn’t leaking so I went into the pump house.

I found water steadily dripping from the inside of the well pump pressure switch. This isn’t ideal as I’ve been taught that electricity and water do not mix well. I turned off the electricity and removed the switch cover. Yup, water was coming out of the diaphragm area.

A quick trip to the Philomath True Value (The well supply store was closed after noon on Saturdays…) and I was the proud owner of a  Square D FSG2J21M4CP 30/50 PSI Standard Pressure Switch with Low Pressure Cutoff. Or as we laymen like to call it, “that switch thingy for my well”. The price was $8 over the cost of one from Amazon but this is a fine example of a time when you’re happy that brick and mortar retail establishments still exist. I should add here that no switch = no water (not strictly true as I could have manually bypassed it, but that would not be optimal.) Replacement was relatively quick and easy although I had to stay home instead of going out to yet another kid’s birthday party with the boys and Felice. Darn. I’ll be checking it every now and then for the rest of the day to make sure nothing leaks.

I tore open the old switch and found a lot of silt, which isn’t unusual for a well.

I removed the diaphragm cover and diaphragm.

Found the leak, the diaphragm had ripped at the point of contact with the cover plate. I suppose one could make a diaphragm in an emergency, it looks like either nylon or  a high durometer polyurethane. I’ll keep the old parts just in case.

Did I mention the silt?

As I was engaged in the project, Felice mentioned that the lower field’s outside faucet was leaking. Since I had the water off I pulled the valve out to check it. The washer was ripped in half.

Looks like part of the valve cup sheared off (how do these things happen?).

Lucky for me I have a box of random rubber washers, grommets and such. Found a suitable replacement for the washer and the faucet doesn’t leak. I’ll probably replace it or remachine the cup  if it leaks again.

Not a bad 3 hours of fun.

February Is Shorter Than Most Months

This is what we’ve been up to.

Henry took apart a fax machine.

We went for a hike on Bald Hill.

Didn’t see any newts though.

I made a really narrow LED display. It uses a Max7219, Arduino and an unknown LED matrix a friend gave me. I have some more Max7219 chips coming to chain together so I can get the whole thing working.
I did buy a Raspberry Pi as well this month. I haven’t done much beyond setting up its SSH server and remoting into it.

And I smashed our old toilet after installing the Gerber Avalanche.
Besides that, not much else. Here are some links:

• Circuitlab
• Hydrogen Drum Machine
• Install MInecraft in Xubuntu
• Fran's Writings on Design and Engineering
• New English Letter Frequency Counts.
• Amazon’s $23,698,655.93 book about flies

Who knows what March will bring, besides those pesky Ides?

Dishwasher Silverware Basket Quick Fix

Our Dishwasher silverware basket.

Half of the compartments have been broken through at the bottom. This means that no silverware can be placed in those compartments. What a pain. Because of the plastic construction all sharp knives must be placed point up, which is relatively unsafe.

Some perforated aluminum sheet. Kent and I picked this up years ago at an auction and I finally found a use.

Cut and placed in the bottom of the compartments, the edges curve slightly and bite into the sides, thus are locked in place. Not as good water flow as the original, but more functional…