A Smarter PSU Converter Leaves the Magic Smoke Inside

Over the years, computers have become faster, but at the same time, more power hungry as well. Way back around the 386 era, most PCs were using the AT standard for power supplies. Since then, the world moved on to the now ubiquitous ATX standard. Hobbyists working on older machines will typically use these readily available supplies with basic adapters to run old machines, but [Samuel] built a better one.

Most AT to ATX adapters are basic passive units, routing the various power lines where they need to go and tying the right pin high to switch the ATX supply on. However, using these with older machines can be fraught with danger. Modern supplies are designed to deliver huge currents, over 20 A in some cases, to run modern hardware. Conversely, a motherboard from the early 90s might only need 2 or 3A. In the case of a short circuit, caused by damage or a failed component, the modern supply will deliver huge current, often damaging the board, due to the overcurrent limit being set so high.

[Samuel]’s solution is to lean on modern electronics to build an ATX to AT adapter with programmable current protection. This allows the current limit to be set far lower in order to protect delicate boards. The board can be set up in both a “fast blow” and a “slow blow” mode to suit various working conditions, and [Samuel] reports that with alternative cabling, it can also be used to power up other old hardware such as Macintosh or Amiga boards. The board is even packed with extra useful features like circuitry to generate the sometimes-needed -5V rail. It’s all programmed through DIP switches and even has an OLED display for feedback.

It’s an adapter that could save some rare old hardware that’s simply irreplaceable, and for that reason alone, we think it’s a highly important build. We’ve talked about appropriate fusing and current limiting before, too – namely, with LED strips. 

 

Case Mod Takes “All In One” Printer to the Next Level

You’ve seen printers with scanners in them, printers with copiers in them, even ones with the ancient technology known as “facsimile” built-in. But have you ever seen a printer with a full gaming computer built into it? No? Well, you still haven’t, technically. There’s no printer to be had anymore inside this re-purposed HP Photosmart 6520 case, but it’s probably the closest we’re going to get.

[Jacob Lee] wrote in to share this awesome build with us, which sees the motherboard, graphics card, ATX power supply, and hard drives all fit seamlessly into the shell of a disused “All-in-one” style printer. Incredibly, he even managed to integrate an LCD into the top; which hinges open when in use and gives a look down into the madness that makes this build tick.

To say there’s a lot of hardware packed into this thing is an understatement. Which is all the more impressive when you consider that he] didn’t take the easy way out for any of it. He could have used a mini-ITX motherboard, or a slim PSU. He could have even dropped the graphics card for integrated. No, [Jacob] is clearly a subscriber to the “Go big or go home” ethos.

As if putting all this gear inside of a normal looking printer case wasn’t impressive enough, he even went as far as adding female ports for Ethernet, HDMI, and USB on the rear of the device to give it a stock look. He mentions there’s some room for improvement with the USB ports, but the power switch and IEC port really look like they could have been original components.

In the age of the Raspberry Pi and other diminutive computers, we don’t see too many proper desktop computer projects anymore. Fewer still that are so well executed and creative. We don’t know how many other people might be trying to stick a computer in a printer case, but if they’re out there, the bar has just been set pretty high.

Not Your Typical ATX Bench PSU

We know what you’re thinking — yet another scrap PC power supply turned into a bench PSU. But look a little closer and you’ll see a nicely designed linear bench supply that just fits inside a gutted ATX case.

A lot of the items on [Medzik]’s BOM for this build are straight from the scrap bin. The aforementioned ATX supply case is one, as is the power transformer donated by a friend. Modules such as the 30V/2A regulator, the digital volt/ammeter, and a thermostat module to control the fan at higher power settings were all sourced via the usual suspects. The PSU boasts two outputs — an adjustable 0-22 volt supply, and a fixed 12-volt output. An unusual design feature is a secondary input which uses the 22-VAC supply from a Weller soldering station to give the PSU a little more oomph. This boosts the maximum output to 30 volts; one wonders why [Medzik] didn’t just source a bigger transformer, but you work with what you have sometimes. There are some nice touches, too, like custom-printed vinyl overlays for the case.

It’s a good-looking and compact unit with a decent suite of features, and you could do a lot worse when building your next bench supply. If it’s not your cup of tea though, just take your pick — tiny and yellow, built to last, or ensconced in Ultrasuede.

The Improved Luggable PC

There are exactly two types of personal computers available today. If you need a lot of horsepower, a powerful GPU, or a full-power CPU, you’re going to end up with a desktop. If you need something portable, you’re getting a laptop with a wimpy CPU and an underpowered GPU. Historically, there has been a third type of PC, the luggable. The luggable is a desktop PC crammed into a case that makes it slightly more portable than a desktop and a monitor.  You cannot buy a luggable PC case right now. They simply do not exist as a commercial product you can shove your own hardware into. This is a form factor an entire industry forgot.

Now there’s a DIY luggable PC. This project from [Roger] packs a standard ATX motherboard, a full-size GPU, a full-size power supply, and everything else that makes a desktop PC powerful into a case that can be stored in an overhead bin.

[Roger] has been working on this project for a while, and it was featured on Hackaday back when it looked like a RepRap Mendel. There have been some significant improvements over the earlier iterations of this project, including a very, very cool hinge mechanism that allows the display to fold in when the computer isn’t being used. It’s a mechanical wonder that prevents scratches. Neat. The rest of the case is constructed out of 2020 aluminum extrusion, and about a one kilogram spool of filament.

Since this is a portable case, there are a few compromises. There are no 5.25″ bays, no 3.5″ bays, and few 2.5″ bays. M.2 SSDs and USB-powered CD drives exist, so this isn’t a big deal.

This is a truly fantastic case in a form factor you can’t buy anywhere else. If you have a spare monitor and a bit of extrusion sitting around, this is one to build yourself.

Reach Out and Touch Your Computer

[Carter Yagemann] found himself in a bit of a pickle. He uses his computer mostly for gaming, but would like to access it remotely from time to time to do a littler server work on the side. The problem is gaming computers eat up a lot of electrons and he didn’t want to waste them by leaving it on all the time. The obvious solution was to use the Wake on Lan function. Unfortunately, his motherboard did not support this technology.

Like any good hacker would do, [Carter] used an IoT board to connect the power button of his PC to the internet. He achieved this goal with a Particle Core board. His motherboard was an ATX variety, so wiring up two of the IoT board’s I/O pins to the power on pins on the motherboard was a simple task accomplished with the help of an inline resistor.

This hack is so easy that it’s a great alternative to the blinky LED first program we all know so well. Want to get started in the hacking community? This is a great way to get going.

SXSW Create: ATX Hackerspace Area

We had a wonderful time over the weekend at the 2015 SXSW Create. I was really excited to see that there was a very large area set aside for the Hackerspaces of the Austin area and they took full advantage of that. Most notably, ATX Hackerspace who had multiple tables and was drawing a huge crowd.

sxsw-atx-thereminThis table is a good example of the demonstrations on hand. Primarily It’s a collection of ultrasonic theremin. The classic theremin uses oscillator-based sound production (we’ve been running a series on that concept) with a set of antennas that uses your body’s proximity to tweak that signal. This version mimics the user interface but greatly simplifies the skillset needed to produce the instrument by swapping the antenna for an ultrasonic rangefinder and generating the audio digitally. The more astute viewer will have noticed the instrument being held. I neglected to ask about this but it sure looks like a Holophonor which is another great seed idea for your next project. Update: it’s a Hulusi.

sxsw-atx-solderingI do think it’s worth noting that ATX also set aside a lot of table-space for their members to actually work on building projects at the event. We’re big advocates of this rather than simply exhibiting finished projects. It doesn’t really matter what you’re working on; seeing a table covered with interesting parts and tools, being worked on by fun people obviously enjoy each other’s company is the core message of a Hackerspace… right?

I talk with [Gardner] about ATX in the video after the break, and make a quick loop around the display tables.

Continue reading “SXSW Create: ATX Hackerspace Area”

Reverse engineer a PSU to change its output voltage

reverse-engineering-psu

[Semicolo] has a bunch of old PSUs on hand which he pulled out of some Lexmark dot matrix printers. In their stock form they put out 40V, which is close to the 35V max he needs to run the stepper motors on a 3D printer he’s been building. So he reverse engineered the PSU to change its output.

On the left you can see the top of the PCB. [Semicolo] flipped it over and snapped a picture of the traces on the bottom of the board. With a bit of work in The Gimp (FOSS image editing software) he was able to convert the traces to black and white. Overlaying the picture of the top with a 50% transparency of the traces made it rather easy see the connections and generate a schematic for the hardware. That’s a really cool trick!

Figuring out how it’s supposed to work is a big step in achieving his goal. The next step was to see if he could bend the circuit to his will. He had previously run across ATX PSU hacks which changed the reference voltage in order to alter the output. He grabbed a datasheet for the HA17431 variable shunt regulator. It lays out how to tune the output based on values of a few external components. He dropped in one resistor and the output measured 31V, well within his target range.