CNC Etch-A-Sketch: Stop Motion Is Logical Next Step

January 26, 2020 by 7 Comments

It happens to everyone. You get your hands on an Etch-A-Sketch for the first time, and armed with the knowledge of how it works, you’re sure you can draw things other than rectangles and staircases. And then you find out the awful truth: you are not as precise as you think you are, and if you’re [QuintBUILDS], the circles you try to draw look like lemons, potatoes, or microbes.

Okay, yes, this definitely isn’t the first CNC-ified Etch-A-Sketch we’ve seen, but it just might be the coolest one. It’s certainly the most kid-friendly, anyway.

Most importantly, you can still pick it up and shake it to clear the screen, a feature sorely lacking in many of the auto-sketchers we scratch about. And if you’re not fully satisfied by this hack, be sure to check out the stop-motion video after the break that turns this baby into a touch-screen video player for Flatlanders.

Turn it over and you’ll find a Raspberry Pi 3 and a CNC hat. The knobs are belt-driven from a pair of NEMA-17 size stepper motors that interface to the knobs with tight-fitting pulleys. Power comes from four 18650s, and is metered by a battery management board that provides both overcharge and drain protection. At some point in the future, [QuintBUILDS] plans to move to a battery pack, because the cell holder is electrically unstable.

We love the welded frame and acrylic enclosure because they make the thing sturdy and portable. Also, we’re suckers for see-through enclosures. They’re clearly superior if you want to do what [QuintBUILDS] did and take it to an elementary school science fair to show the kids just how cool science can be if you stick with it.

If you don’t think motorized Etch-A-Sketches can be useful, maybe you just haven’t seen this clock build yet.

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Hubble Telescope Power Supply Tester On EBay

January 26, 2020 by 38 Comments

Got $75K spare? Then this is the eBay deal for you! [jvanorsdal] pointed us to this eBay bargain: the VPI Vehicle Power Interface Rack & Console Hubble Space Telescope. This was the actual system used to test the power systems of the Hubble Space Telescope before it was launched, so it’s a genuine piece of space history.

For the price you get two, yes two CRT displays, six HP power supplies and a huge amount of hand-wired history. Even if you aren’t going to bid, it is worth taking a look at the insides of this thing, as it is all hand-soldered and the cable routing is a thing of beauty. I have absolutely no use for this, but I totally want it for my living room.

There are a few gotchas, though. Because it is NASA space hardware, you can’t export it to places like Iran, and the shipping cost for the US is a cool $1.5K. Considering the size of the thing, that is not so bad, perhaps: it is built into a three rack metal cabinet with built-in wheels that measures over 7 feet long and weighs over 800 lbs.

Interested? It is on sale for $75k, and there is a handy buy it now button on the site.

We all love space history here at Hackaday. Back in 2019, our own [Tom Nardi] got to spend an evening with the Space Shuttle Atlantis.

Keeping A 3D Printed NAS Updated With The Times

January 26, 2020 by 28 Comments

Back in 2018, [Paul-Louis Ageneau] created a 3D printed network-attached storage (NAS) enclosure for his Raspberry Pi. The design worked well, the Internet liked it when he posted the details on his blog, and all was right with the world. But of course, such glories are fleeting. Two years later that design needs updating, and thanks to the parametric nature of OpenSCAD, he’s been able to refresh his design for another tour of duty.

In our book, this is as much a cautionary tale as it is a success story. On one hand, it’s a testament to the power of CAD and desktop 3D printing. That a design can be tweaked and reproduced down the line with only minimal hassle is great for folks like us. But it’s also a shame that he didn’t get more than two years before some of the parts he used in the original NAS became unobtainium.

The main issue was that the integrated USB hub he used for the first version is no longer available, so the design had to be modified to accept a similar board. Unfortunately, the new hub is quite a bit wider than the old one. Resizing the entire case isn’t really an option since the Pi has to slide into it, so the hub now bumps out a bit on one side. He’s added a printable cover that cleans it up a bit, but the asymmetrical look might be a problem for some. While fiddling with the design, he also changed around the cooling setup so a larger fan could be mounted; now that the Raspberry Pi 4 is out, it can use all the cooling help it can get.

We covered the original version of the printed NAS back when it was first released, and it’s always good to see a creator coming back and keeping a project updated; even if it’s because hardware availability forced their hand.

Put The Power Of PCR In Your Pocket With This Open-Source Thermal Cycler

January 26, 2020 by 23 Comments

When the first thermal cyclers for the polymerase chain reaction came out in the 1980s, they were as expensive as a market driven by grant money could make them. Things haven’t got much better over the years, largely shutting STEM classes and biohackers out of the PCR market. That may be about to change, though, if the €99.00 PocketPCR thermal cycler takes hold.

PCR amplifies DNA in a three-step process: denaturation, which melts double-stranded DNA into single strands; annealing, which lets small pieces of primer DNA bind to either side of the region of interest; and elongation, where the enzyme DNA polymerase zips along the single strands starting at the primer to replicate the DNA. The cycle repeats and copies of the original DNA accumulate exponentially. Like any thermal cycler, [Urs Gaudenz]’s PocketPCR automates those temperature shifts, using a combination of PCB-mounted heating elements and a cooling fan. The coils rapidly heat a reaction block up to the 99°C denaturation temperature, the fan brings that down to the 68°C needed for annealing, and then the temperature ramps back up to 72°C  for elongation with thermostable DNA polymerase. PID loops keep the reaction temperature precisely controlled. The whole thing is, as the name suggests, small enough to fit in a pocket, and can either be purchased in kit form or scratch-built from the build files on GitHub.

We applaud [Urs]’ efforts to get the power of PCR into the hands of citizen scientists. Quick and dirty thermal cyclers are one thing, but Pocket PCR has a great fit and finish that makes it more accessible.

Thanks to [Abe Tusk] for the tip.

Tracking Cancer Treatment With An ESP8266-Based Radiation Sensor

January 25, 2020 by 22 Comments

Those of us who have not been in that position can only imagine the anguish of learning that your teenager has cancer. This happened to [Rob], whose child was diagnosed with papillary thyroid cancer. It’s a condition that can be treated with surgery followed by a course of radioactive iodine to kill any remaining cancer cells. During iodine treatment, the patient is radioactive enough that other people must maintain a distance of 3m from them, and as a learning exercise for both father and teen he created and refined the design of a portable wireless radioactivity monitor.

There are a variety of sensors for radiation monitoring including the well-known Geiger–Müller tube, but he settled on a PIN photodiode based sensor supplied by radiation-watch.org. This sensor is not at its most sensitive at the energy levels emitted by the iodine isotope used in the treatment, but the relatively high intensity of the radiation meant that enough would register for a useful reading to be taken. The sensor board he was mated to an ESP8266 module. [Rob] went through three iterations of the balance of the hardware before settling on a lithium-ion battery and a plastic case.

On the software side, the ESP connects to an MQTT server, from which a CSV file of data is derived. On a computer, the CSV data is collected and plotted to a graph. The data take during treatment clearly shows the reduction in radiation following the isotope’s half-life. The graph isn’t perfect though, there is a gap due to the second prototype’s batteries running flat

From his epilogue it appears that his son has recovered, and we wish them further good health. The details have been published in the hope that other young people facing the same trial might benefit from building their own radiation monitor.

A Custom Raspberry Pi 4 Arcade Cabinet

January 25, 2020 by 29 Comments

Over the years we’ve covered quite a few Raspberry Pi based arcade cabinets, and admittedly many of them have been fairly similar. After all, there’s only so much variation you can make before it stops looking like a traditional arcade machine. But even still, we never tire of seeing a well executed build like the one [Dawid Zittrich] recently shared with us.

These days you can order a kit that has pre-cut panels to build your cabinet with, but looking for a completely custom build, [Dawid] decided to first model his design in SketchUp and then cut out the panels himself with a jigsaw. This obviously is quite a bit more work, and assumes you’ve got sufficient woodworking tools, but we think the final result looks great. Not to mention the fact that it’s going to be a lot stronger than something made out of MDF.

He also created the side artwork himself, taking the logos and names from his favorite arcade and Amiga games and putting them on a retro-looking gradient pattern.  The marquee on the top has an acrylic front and is illuminated from behind with strips of LEDs. It’s mounted on a hinge so that it can be lifted up and a new piece of art slid in without taking apart the whole cabinet. While it might be a little more labor intensive to switch out than some of the electronic marquees we’ve seen, we do like that you still have the ability to change the artwork on a whim.

With the cabinet itself completed, [Dawid] turned his attention to the electronics. Inside you’ve got the aforementioned Raspberry Pi 4 (with a Noctua fan to keep it cool), an external hard drive, a HDMI to VGA converter with scanline generator to drive the 4:3 ratio Eizo Flex Scan S2100 monitor, and a rather beefy amplifier hanging off the Pi’s 3.5 mm analog audio output. All of which is easily accessible via a maintenance hatch built into the cabinet so [Dawid] doesn’t need to tear everything down when he wants to tweak something.

If you’d like to have that arcade cabinet feel but don’t have the space and equipment to put something like this together, you could always stick a Raspberry Pi into an iCade and call it a day.

Porting Quake To An IPod Classic Is No Easy Task

January 25, 2020 by 9 Comments

We didn’t think we’d see another hack involving the aging iPod Classic here on Hackaday again, yet [Franklin Wei] surprises us with a brand new port of Quake for the sixth-generation iPod released some thirteen years ago. Is Quake the new 90s FPS that’ll get put into every device hackers can get their hands on?

The port works on top of RockBox, a custom firmware for the iPod and other portable media players. This isn’t the first game on the device. A source port of Doom has been available for years. [Franklin] decided to use Simple DirectMedia Layer (SDL) to make his job easier. That doesn’t mean this was an easy task though, as [Franklin] describes very interesting bugs that kept him from finishing his work for about two years.

The first problem was that the GCC compiler he was using was apparently not optimizing time-critical sound mixing routines. [Franklin] decided enough was enough and dug into ARM assembly to re-write those parts of the code by hand. He managed to squeeze out a speed increase of about 60%. Even better, he ran into a prime example of a bug that would get triggered by a very specific sound sample length running through his code. Thankfully, with all of that sorted, the port is now released and we can all enjoy cramping our hands around tiny screens to frag some low-poly monsters.

If you need to repair your sixth-generation iPod before you can do that though, no need to worry since they seem to not be so hard to service by yourself. And if the battery life and disk space aren’t quite what they used to be, there’s also the option to bulk it up for winter. Check out the Quake port in action after the break.

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