Wearable Hacks

807 Articles

A styrofoam head wearing an electronic headband with cat ears

These Mind-Controlled Cat Ears Move With Your Mood

March 19, 2022 by 15 Comments

As any cat owner will tell you, a cat’s ears are great indicators of its state of mind: pointed forward if they want your attention, turned backwards if they’re angry, and folded down flat when they’re afraid. Humans sometimes don cat ear headbands as a fashion statement, but sitting motionless those ears are more likely to confuse a cat than to provide any meaningful communication.

[Jazz DiMauro] aims to fill that gap by designing a cat ear headband that actually responds to your emotions. It does so by continuously taking an EEG measurement and extracting the “attention” and “meditation” variables from it. Those values are then applied to a set of servos that allow two-axis motion on each 3D printed ear. The EEG readout device is an off-the-shelf MindWave headset, which outputs its sensor data through Bluetooth. An Arduino then reads out the data and drives the servos.

Turning all this into a usable wearable device was a project on its own: [Jazz] went through several iterations to find a suitable power source and wiring strategy until they settled on a pair of lithium-polymer batteries and a single flat cable. The end result looks comfortable enough to wear, and the ears’ motion looks smooth and natural. All that’s left is to test it with real cats, to find out if they can now finally understand their human’s emotions too.

We’ve featured a few moving cat ear headbands before: one that moves along with your head’s motions, and another one with manual control. Today’s EEG-powered one shows yet another application for EEGs, which have been used for anything from invoking lucid dreaming to playing beer pong. Continue reading “These Mind-Controlled Cat Ears Move With Your Mood” →

Row of white 3D printed shoes in different styles

CAD Up Some Shoes, But Don’t Start From Scratch

March 3, 2022 by 14 Comments

Nothing helps a project get off the ground better than a good set of resources, and that’s what led [DaveMakesStuff] to release his Digital Shoe Design Kit, which is a set of 3D models ready to customize into a basic running shoe.

This is exactly what is needed for people who are interested in designing a custom shoe, but perhaps not interested in modeling every element entirely from scratch. [DaveMakesStuff]’s resources allows one to mix outsoles, midsoles, uppers, and other basic shoe elements into a finished model, ready to be resized or even 3D printed if desired. The files are all in stl format, but resizing stl files is trivial, and more advanced editing is possible with mesh sculpting programs like Blender.

If the gears in your head are starting to turn and you are wondering whether it is feasible to 3D scan your feet for some experiments in DIY custom footwear, take a few minutes and read up on 3D scanning and what to expect from the process to hit the ground running.

Compressed Air Jumping Shoes Are Not For The Faint-Hearted

March 3, 2022 by 30 Comments

[Ian Charnas] has taken a short break from building things that might injure himself, by building something that could injure somebody else instead. (Video, embedded below) Well, hopefully not anyway. After working with YouTuber [Tyler Csatari] on a few ideas, [Tyler] was insistent on getting some power-assisted jumping shoes, so [Ian] set to work mounting some compressed-air powered pistons to a pair of walking shoes. With a large backpack housing the 200 PSI air cylinder, control valves and timers. The whole affair looks solidly constructed, if a little ungainly, but does seem to work surprisingly well.

After some initial calculations of how much force each piston could exert before risking leg injury, he found that whilst it did work, to an extent, the pressure required was beyond the capability of the compressor they had on hand. After a shopping trip, a bigger compressor was located, but that still needed a modification to get anywhere near its maximum 200 psi rating. The thing is, that modification was to bypass the regulator and the safety valve, and this is definitely something you don’t want to be making a habit of. Compressed air systems like this can hold quite a bit of an explosion potential if pushed beyond reasonable limits, and care needs to be taken to keep things within safe bounds.

Cost-wise, [Ian] does mention a figure of around $3,000 USD making it a bit of a pricey project, but hey a YouTuber’s paying the bill, so it must just be a drop in the ocean for them?

Just to illustrate how useful compressed air is as a method of storing energy, here’s a compressed-air powered helicopter, and a 3D printed wankel rotary engine, which must’ve been tough to dial in and get working!

Continue reading “Compressed Air Jumping Shoes Are Not For The Faint-Hearted” →

Three pendants that the article is describing, on a drafting mat.They're heart-shaped red PCBs with LEDs all around its perimeter, two CR2032-like batteries in its center.

Heart-Shaped Heartwarming Valentine’s Day Pendant

January 24, 2022 by No comments

This is no ordinary heart-shaped PCB pendant project! To us, it’s also symbol representing the striking amount of love that [SaltyPaws] has put into its design and documentation. He tells us that he designed it for the two daughters he is raising, as an electronics and general STEAM introduction – with outstanding educational and aesthetic qualities, giving insights into a wide range of topics while looking . The PCB is mostly through-hole, making for easy soldering and quick return on the effort investment. The project is thought-out beyond the PCB, however – this pendant is designed to be wearable day-to-day, which is why it’s accompanied by a 3D-printed frame, protecting its wearer from sharp PCB edges and through-hole lead ends!

Open-sourcing things is a gift, and today, we are also the recipients. [SaltyPaws] has open-sourced everything involved – PCB files, 3D cover files, firmware, BOM, everything you would need to build your own version. All of this is in a GitHub repository, with detailed sourcing and assembly instructions in the README.md – we couldn’t ask for more! If you have loved ones that would take delight in putting such a pretty pendant together, you have about a week to order the PCBs – after that, Chinese New Year will likely thwart your plans!

Looking for more accessories that double as electronics projects? We’ve covered a wide variety, even when it comes to pendants alone – check out this edge-lit fluorescent acrylic educational Maker Faire accessory, or this circuit sculpture BEAM-inspired bird-imitating one, or this tiny SAMD21-powered pendant with an IPS LCD!

Silicone Devices: DIY Stretchable Circuits

January 23, 2022 by 12 Comments

Flexible circuits built on polyimide film are now commonplace, you can prototype with them at multiple factories, at a cost that is almost acceptable to your average hacker. Polyimide film is pretty tough for something so thin, but eventually it will tear, and with larger components, bend radii are quite restricted. But what about stretchable circuits, as in circuits you can flex, twist and stretch? Let us introduce silicone devices. A research group from Hasselt University, Belgium, have been prototyping making truly flexible, silicone-based circuit substrates, managing to integrate a wide range of SMT component types with a dual layer interconnect, with vias and external contacts.

It should be possible to reproduce the process using nothing more special than your average Makerspace CO2 laser cutter, and a couple of special tools that can be easily made — a guide for that is promised — it is purely a matter of gathering a few special materials, and using off-cuts you have lying around for the rest. The interconnect uses Galinstan, which is a low melting point alloy of gallium, indium, and tin. Unfortunately, this material is fairly expensive and cannot be shipped by air due to the gallium content, without specialised handling, at considerable expense. But that aside, other than some acrylic sheets, some vinyl, copper foil and a few sprays, nothing is beyond reach.

The construction process is reverse to what we normally see, with the components and copper contact plates placed first, on to a primed vinyl sheet. This sheet is laser marked with the component outlines to enable them to be corrected placed. Yes, that’s right, they’re using a laser cutter to mark vinyl, a chlorine-containing plastic. Hold on to that thought for a bit.

Insulating layers and substrate layers are constructed by blade-coating with a layer of clear silicone. Interconnect layers are formed by sticking a fresh vinyl sheet onto the exposed contacts and laser cutting just though it to expose the pads and the interconnect traces. Next the fancy Galinstan is applied by brush and the vinyl stencil removed. Rinse and repeat for the next layer of insulating silicone, more circuit traces, then use the laser cutter to precisely etch through the via regions to allow more metalisation to be added. Finally a coating of silicone is applied over the whole assembly, the laser is again used to etch the silicone away from the contact pads, and with a little solder tinning of these, you’re done. Simple, if only our Makerspaces didn’t have rules against laser cutting vinyl.

This was clearly a very brief overview, here is a very detailed instructables guide ready for you, as well as a formal research paper, detailing why this came about and why you might want to try this yourself.

If you’re into custom wearables, you might remember this earlier piece about silicone circuits, and this one weird organic-looking thing from the same time-frame.

Continue reading “Silicone Devices: DIY Stretchable Circuits” →

Remoticon 2021 // Debra Ansell Connects PCB In Ways You Didn’t Expect

January 20, 2022 by 21 Comments

“LEDs improve everything.” Words to live by. Most everything that Debra Ansell of [GeekMomProjects] makes is bright, bold, and blinky. But if you’re looking for a simple string of WS2812s, you’re barking up the wrong tree. In the last few years, Debra has been making larger and more complicated assemblies, and that has meant diving into the mechanical design of modular PCBs. In the process Debra has come up with some great techniques that you’ll be able to use in your own builds, which she shared with us in a presentation during the 2021 Hackaday Remoticon.

She starts off with a quick overview of the state of play in PCB art, specifically of the style that she’s into these days: three dimensional constructions where the physical PCB itself is a sculptural element of the project. She’s crossing that with the popular triangle-style wall hanging sculpture, and her own fascination with “inner glow” — side-illuminated acrylic diffusers. Then she starts taking us down the path of creating her own wall art in detail, and this is where you need to listen up. Continue reading “Remoticon 2021 // Debra Ansell Connects PCB In Ways You Didn’t Expect” →

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.