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.

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Reverse engineer a PSU to change its output voltage


[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.

Ask Hackaday: What’s an easy way to build a potentiometer for a soldering iron?


[Lee] wrote in to share the work he’s done in building a controller for his soldering iron. The idea started when he was working with an ATX power supply. He figured if it works as a makeshift bench supply perhaps he could use it as the source for an adjustable iron. To get around the built-in short-circuit protection he needed a potentiometer to limit the current while allowing for adjustments. His first circuit used a resistor salvaged from an AT supply and a trimpot from some computer speakers. That melted rather quickly as the pot was not power rated.

This is a picture of his next attempt. He built his own potentiometer. It uses the center conductor from some coaxial cable wrapped around the plastic frame of an old cooling fan. Once the wire was in place he sanded down the insulation on top to expose the conductor. The sweeper is a piece of solid core wire which pivots to connect to the coil in different places. It works, and so far he’s managed to adjust a 5V rail between 5A and 20A.

How would you make this system more robust? Short of buying a trimpot with a higher power rating, do you think this is the easy way to build a soldering iron controller? Let us know by leaving your thoughts in the comments.

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Giving an ATX bench supply the case it deserves

Your bench supply doesn’t need to look sad just because you’re using an ATX power supply instead of a commercial product. Follow [Ian Lee’s] example and you could have beautiful wooden enclosures for the tools in your own shop.

The woodworking skills used here aren’t all that advanced, but you need to have a knack for it so we suggest running some test pieces before you start the actual build. [Ian] ran a dado for the front and back panel in each piece of the wood sides. At each corner the inside of the the pieces were mitered at 45 degrees. To put it all together he laid the pieces end to end on a the work bench, then applied painters tape to the outside of the joints. This holds the joints together so that he can flip the collection over, apply glue, and then start hinging the sides into place. It’s almost like rolling up a box.

As with other ATX supply projects we’ve seen [Ian] designed this so that the PSU can be swapped out later if necessary. Instead of wiring his own cable harness he used an ATX breakout board. To get the interface layout he wanted he mounted the banana jacks separately and just ran jumper cables back to that board.

ATX benchtop conversion retains safety features, delivers plenty of current.


[Bogin] was looking to add a benchtop power supply to his array of tools, but he didn’t really find any of the online tutorials helpful. Most of what he discovered were simple re-wiring jobs utilizing LM317 regulators and shorted PS-ON pins used to keep the PSUs happily chugging along as if nothing had been changed. No, what [Bogin] wanted was a serious power supply with short circuit protection and loads of current.

He started the conversion by disassembling a 300 watt ATX power supply that uses a halfbridge design. After identifying the controller chip, a TL494 in this case, he proceeded to tweak the PWM feedback circuit which controls the supply’s output. A few snips here, a few passes with a soldering iron there, and [Bogin] was ready to test out his creation.

He says that it works very well, even under heavy load. His tutorial is specific to these sorts of PSUs, so we would be more than happy to feature similar work done with those that implement other design topologies. In the meantime, be sure to check out a video of the hacked power supply in action below.

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Building a bench supply without altering the ATX psu

[FozzTexx] has been using a bench supply he made from an AT PSU for years. He put a lot of work into that one, removing unnecessary wires, mounting banana plug jacks on the metal case, and adding an on/off switch and labels. But if it ever dies on him it will be a major pain to do all that work again in order to replace it. When he set out to build another bench supply from an ATX PSU he decided to do so without altering the PSU. This way he can easily swap it out for a different one if he ever needs to.

The hardest part of the hack was sourcing connectors. But with the parts in hand he’s able to just plug the faceplate into the stock connector. This gives him access to all of the voltages, and provides an on/off switch and indicator light. He might also want to add the option of resetting the unit if the over-current protection kicks in.