Resin Stacking Proves Messy And Difficult

December 12, 2021 by 15 Comments

3D printers are typically the tool you use when you want a one-off quick prototype. However, more and more, they’re being used to produce things in quantity. [Uncle Jessy] decided to try out the resin stacking technique in order to quickly produce many figurines on his resin printer. However, not everything went exactly to plan.

The technique is simple. The idea is to produce many copies of an object in a single continuous print on a resin 3D printer. To achieve this, the object is cloned many times, and scaffolding is created to allow the stacking of multiple objects on top of each other. This must be done carefully to avoid ruining the geometry of the object, and similarly to support material, uses more resin in the process.

[Uncle Jessy] experimented several times, but ran into multiple issues with the process when trying to print out some small Magneto figurines. An initial experiment using a raft failed when the print fell off the build plate. With the raft removed, the second print failed as the scaffolding didn’t print quite right. Further tweaks and beefing up the scaffold improved things, and [Jessy] managed to print 93 figurines in a single operation.

It’s a useful technique if you want to print a ton of models on a resin printer in as short a time as possible. However, expect to spend plenty of resin as you refine the technique. You’ll also need a big wash tank to clean the prints during post-processing. Video after the break.

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An Atari 130XE's keyboard made mechanical with Kailh box pinks and 3D-printed keyswitch stems.

Atari 130XE Keyboard Now Goes Clack

December 12, 2021 by 10 Comments

Performing a resto-mod on a beloved piece of childhood technology can be quite a ride. In [Bertrand]’s case, it was the keyboard to their Atari 130XE. Although it has those cool double-shot keycaps, they’re hiding a crappy membrane underneath that could really benefit from a mechanical upgrade. Relax — the membrane part was broken.

[Bertrand] designed and printed some new stems for Kailh box pinks that can accept both of the two known variants instead of the standard Cherry MX receptacle. He also made a new PCB (natch) and a keyboard adapter to replace the membrane interface, and had a steel keyswitch plate custom cut. The so-called Atari 130MX mod can be used with an Atari 130XE computer, or as a regular keyboard for a PC if you solder in a Pico.

[Bertrand] says that this labor of love was meant to be reproduced and told us that for some folks in the Atari community, it’s already on like Donkey Kong. If you’re going to attempt this mod, know that filament printers won’t work well at all for these tiny and precise parts. [Bertrand] printed the stems on an Elegoo with a resolution of 1/20 mm (50 micrometers). On the bright side, old-new stock Atari keycaps are not that hard to find. Check it out after the break.

We love to see vintage keyboards get modern upgrades. Did you see the nuclear missile silo keyboard/trackball combo? When we read that it came from ebay, our wallet took itself to DEFCON 1.

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A Nested Gear Clock

December 12, 2021 by 11 Comments

One of the most common projects we see here at Hackaday is a clock. It could just be that we as humans are fascinated by the concept of time or that making a piece of functional art appeals to our utilitarian sense. In that spirit, [Alexandre Chappel] set out to make a large mechanical clock with complex gears.

The initial design was made in Fusion360 over a week and then in a somewhat bold move, [Alexandre] started up the CNC and cut all the parts out of valchromat. The basic idea of the clock is that the numbers move on the clock, not the hands. So the clock should show 10:25 instead of moving hands to the 10 and the 5. Most of the clock is made of up stacked gear assemblies, geneva drives, and many bearings. A single stepper motor drives the whole clock, which [Alexandre] admits is a bit of a cheat since trying to add springs and an escapement would add complexity to an already complex clock. He did have to adjust and recut a few gears but most of the assembly came together nicely. Some 3d printed numbers dropped into the CNCed slots offers much-improved readability.

A few problems became apparent once the system was together. The numbers don’t quite line up perfectly, which is unfortunate. He mentioned that tighter tolerances on the gears would likely help there. A fatal design flaw on the smallest disk became apparent as it needs to turn a sixth of the circle whereas the outer circle is just turning a tenth of the circle. Mechanical advantage isn’t in [Alexandre’s] favor and the stepper skips some steps and it slowly makes its way towards the next second digit of the hour.

If you’re looking for more beautiful artistic clocks, why not check out this circuit sculpture one?

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Customize These 3D Printed Cases

December 12, 2021 by 27 Comments

Building something, of course, requires your electronics skills. But packaging it is often an exercise in mechanics. You can buy off the shelf, of course, but sometimes it is hard to find just the right enclosure. You probably have a 3D printer, too, but sometimes 3D printing an entire case can be time consuming and isn’t always completely attractive. Enter [Johannes-Bosch] and Fusion 360. These 3D printed frames assemble into boxes and are easy to customize. The panels are aluminum, although we imagine you could substitute wood, acrylic, or even a 3D printed sheet of plastic, if you wanted to.

The video below shows some examples. If your German isn’t up to snuff, ask YouTube to automatically translate the subtitles and you’ll get the idea.

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flow chart for Assessment of the Feasibility of Using Noninvasive Wearable Biometric Monitoring Sensors to Detect Influenza and the Common Cold Before Symptom Onset paper

Wearables Can Detect The Flu? Well…Maybe…

December 12, 2021 by 15 Comments

Surprisingly there are no pre-symptomatic screening methods for the common cold or the flu, allowing these viruses to spread unbeknownst to the infected. However, if we could detect when infected people will get sick even before they were showing symptoms, we could do a lot more to contain the flu or common cold and possibly save lives. Well, that’s what this group of researchers in this highly collaborative study set out to accomplish using data from wearable devices.

Participants of the study were given an E4 wristband, a research-grade wearable that measures heart rate, skin temperature, electrodermal activity, and movement. They then wore the E4 before and after inoculation of either influenza or rhinovirus. The researchers used 25 binary, random forest classification models to predict whether or not participants were infected based on the physiological data reported by the E4 sensor. Their results are pretty lengthy, so I’ll only highlight a few major discussion points. In one particular analysis, they found that at 36 hours after inoculation their model had an accuracy of 89% with a 100% sensitivity and a 67% specificity. Those aren’t exactly world-shaking numbers, but something the researchers thought was pretty promising nonetheless.

One major consideration for the accuracy of their model is the quality of the data reported by the wearable. Namely, if the data reported by the wearable isn’t reliable itself, no model derived from such data can be trustworthy either. We’ve discussed those points here at Hackaday before. Another major consideration is the lack of a control group. You definitely need to know if the model is simply tagging everyone as “infected” (which specificity does give us an idea of, to be fair) and a control group of participants who have not been inoculated with either virus would be one possible way to answer that question. Fortunately, the researchers admit this limitation of their work and we hope they will remedy this in future studies.

Studies like this are becoming increasingly common and the ongoing pandemic has motivated these physiological monitoring studies even further. It seems like wearables are here to stay as the academic research involving these devices seems to intensify each day. We’d love to see what kind of data could be obtained by a community-developed device, as we’ve seen some pretty impressive DIY biosensor projects over the years.

Comfortable, wearable packaging for biometric device for monitoring physiological data and pushing the data to the cloud

A DIY Biometric Device With Some Security Considerations

December 11, 2021 by 8 Comments

Biohacking projects are not new to Hackaday and it’s certainly a genre that really piques our interest. Our latest biohacking device comes courtesy of [Manivannan] who brings his flavor of a wearable biosensor with some security elements built-in through AWS.

The hardware is composed of some impressive components we have seen. He has an AD8232 electrocardiogram front end, the MAX30102 integrated pulse oximeter IC for determining blood oxygen and heart rate, and the ever-popular LM35 for measuring body temperature. Either of these chips would be perfect for your next DIY biosensor project though you might try the MAX30205 body temperature sensor given its 0.1-degree Celsius accuracy. However, what really piqued our interest was the use of Microchip’s AVR-IoT WA Development Board. Now we’ve talked about this board before and also mentioned you could probably do all the same things with an ESP-device, but perhaps now we get to see the board a bit more in action.

[Manivannan] walks the reader through the board’s setup and everything looks to be pretty straightforward. He ultimately rigged together a very primitive dashboard for viewing all his vitals in real-time, demonstrating how you could put together your own patient dashboard for remote monitoring of vitals or other sensor signals. He emphasizes that all this is powered through AWS, giving him some added security layers that are critical for protecting his data from unwanted viewers.

Though [Manivannan’s] security implementation doesn’t rise to the standard of medical devices, maybe it will serve as a case study in the growing open-source medical device movement.

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We All Live In A PVC Submarine

December 11, 2021 by 11 Comments

We doubt you could really live in [Pena’s] PVC submarine, but now the song’s stuck in our head anyway. Although the post is in Portuguese, you can get a pretty good idea of how it works, and translation software is better than ever. Transcending the language barrier, there are videos of just about every step of the construction. We didn’t, however, find a video of the vehicle in the water.

The plumber’s delight has modified motors for thrusters, and a camera as well. Epoxy potting keeps things waterproof. We’ve seen candle wax used for the same purpose in other builds.

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