The Tracer board strapped to the frame of a bicycle with a red Velcro strap

Tracer, A Platform For All Things Movement Logging

April 1, 2022 by Arya Voronova 2 Comments

[elektroThing] is building a lightweight, battery-powered board to track and measure movement of all kinds, called Tracer. Powered by an ESP32, it has a LSM6DSL 6DoF accelerometer & gyroscope sensor, and a VL53L0X Time-of-Flight sensor. A small Li-ion battery in a holder reportedly provides for 5 hours of streaming data over Bluetooth Low Energy (BLE) at 100 Hz. It’s essentially a wireless movement sensor platform to be paired with a more powerful computer for data logging and analysis. What’s such a platform good for?

They show it attached to a tennis racket, saying you could use the data to, for a start, count the strokes done in a given match. They’ve also strapped it to a bicycle’s crankshaft and used it as a cadence sensor – good for gauging your cycling efficiency! But of course, this can be used in more applications than sport. A device like this could be used for logging movement of any relatively nearby objects, be it your cat, an office chair, or a door someone might slam a bit too hard at times. Say, you wanted to develop a sleep tracker and were to collect some data for defining your algorithms and planning your hardware requirements – this would work wonders.

There’s already available example code for streaming data into the Phyphox data logging and graphing app, as well as schematics – hopefully, the full board files will be available soon. A worthy open-source opponent to commercial devices available for similar purposes, this platform is good news for any hacker that wants to do motion measurement projects without reinventing quite a few wheels at once. We are told this board might get to CrowdSupply soon, and we can’t wait! Platforms like these, if done well, can grow an offspring of new projects for us to have fun with, and our paid projects get all that much easier to work on.

We’ve shown projects with such sensors before – here’s one that helps your rifle aim by giving you data to debug your last-second rifle movements, and another that logs movement data from inside a football. There’s a million endpoints you could stream your data into, and we are told you could even use Google Sheets. Just a year ago, we held our Data Logging contest and the entries we received will surely point out quite a few under-explored areas in your daily life!

Human Power, Past And Future

March 1, 2022 by Al Williams 54 Comments

We will assume you’ve seen The Matrix — it was from 1999, after all. The surprise, at the end, was that humans were being used as human batteries to power a civilization of intelligent machines. But aside from just putting out some heat, the idea does have some precedent. After all, humans powered machines like mills, sewing machines, and pumps for centuries before there were good alternatives.

History

Galley ship — Reconstruction of a squadron of ancient Greek galley ships.

Early machines used hand cranks, treadwheels, treadles, and even pedal power to harness energy from humans. Consider, for example, an ancient galley ship with many oarsmen providing an engine. This wasn’t a great use of human power. An oarsman on a galley used his arms and back but didn’t much use his legs. The legs, though, have larger muscles and are often stronger. A pedal boat or racing shell would have been much more efficient, but without mass production of strong metal parts, it would have been difficult to build and maintain such machines in ancient times.

There was a time when pedals or treadles operated lots of machines from sewing machines to lathes. There were even old radios able to transmit and receive with no external power thanks to pedals as late as the 1940s.

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Silicone Devices: DIY Stretchable Circuits

January 23, 2022 by Dave Rowntree 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.

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At MIT, Clothing Fiber Watches You

June 7, 2021 by Al Williams 11 Comments

[Yoel Fink] and his team at MIT have announced their creation of a fiber that can sense and store data. In addition, they can use data from a shirt made of the material to infer the wearer’s activity with high accuracy. The fiber contains hundreds of microscale silicon chips into a preform used to create a polymer fiber that connects the chips using four 25 micron tungsten wires. You can read the paper directly in Nature Communications.

The fiber contains temperature sensors and enough memory (24CW1280X chips) to store a short movie for two months without power. It also contains 1,650 neural network elements, which means the fiber can train to infer activity itself without additional help.

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Finishing Your Projects Hack Chat With Zack Freedman

February 8, 2021 by Dan Maloney 15 Comments

Join us on Wednesday, February 10 at noon Pacific for the Finishing Your Projects Hack Chat with Zack Freedman!

Try as we might, some of us are much better at starting projects than finishing them. Our benches — or all too often, our notebooks — are graveyards of good attempts, littered with the scraps of ideas that really sounded good at the time and clouded by a miasma of good intentions and protestations that “This time, it’ll be different.” Spoiler alert: no, it won’t.

Trying to pin the cause of this painfully common problem on something specific is probably a fool’s errand, especially when given the fact that some people mysteriously don’t suffer from it, it would appear brain chemistry plays a role. Maybe some people just really like the dopamine hit of starting something new, which gives them the rush of excitement while the idea is still fresh, only to have it wane rapidly as the project enters the churn.

Whatever it is, if you suffer from it, chances are good you’ve looked for a way out at least once. If so, you’ll want to hop into this Hack Chat, where “very serious hacker” Zack Freedman, proprietor of the Voidstar Labs channel on YouTube, will share his thoughts on project follow-through. We’ve enjoyed Zack’s projects for a while now, and covered a few, from his in-your-face (on-your-wrist?) smartwatch to his video editing keypad. He gets stuff done, perhaps in part due to his workshop organization, but however he does it, we’re eager to hear about it. Join us as we discuss the art of follow-through and getting stuff done.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 10 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Wearable Sensors On Your Skin

November 7, 2020 by Chris Lott 10 Comments

An international team at Penn State led by [Larry Cheng] made a breakthrough in printing sensors directly on skin without heat. The breakthrough here is the development of a room-temperature sintering technique. Typical sintering of copper happens at 300 C, and can be further lowered to 100 C by adding nanoparticles. But even 100 C is too hot, since skin starts to burn at around 40 C.

You can obtain their journal article if you want the details, but basically their technique combines the ingredients in peelable face masks and eggshells. With this printed circuit is applied to the skin, the sintering process only requires a hair dryer on the cool setting, and results can bend and fold without breaking the connections. A hot shower will remove the circuit without damaging the circuit or your skin. [Larry] says the circuits can be recycled.

They are using these sensors to monitor temperature, humidity, blood oxygen levels, and heart performance indicators. They’ve even linked these various on-body sensors with a WiFi network for ease of monitoring. After reading this report, we’re left wondering, if the sensor is directly on your skin, can it be really called wearable?

We’ve written about printable inks before, but for printed circuit board applications. We can’t help but wonder if this technology would help solve some problems inherent in that technology, as well. Thanks to [Qes] for the tip.

Stop Bad Laws Before They Start

July 25, 2020 by Elliot Williams 88 Comments

With everything else going on this summer, you might be forgiven for not keeping abreast of new proposed regulatory frameworks, but if you’re interested in software-defined radio (SDR) or even reflashing your WiFi router, you should. Right now, there’s a proposal to essentially prevent you from flashing your own firmware/software to any product with a radio in it before the European Commission. This obviously matters to Europeans, but because manufacturers often build hardware to the strictest global requirements, it may impact everyone. What counts as radio equipment? Everything from WiFi routers to wearables, SDR dongles to shortwave radios.

The idea is to prevent rogue reconfigurable radios from talking over each other, and prevent consumers from bricking their routers and radios. Before SDR was the norm, and firmware was king, it was easy for regulators to test some hardware and make sure that it’s compliant, but now that anyone can re-flash firmware, how can they be sure that a radio is conformant? Prevent the user from running their own firmware, naturally. It’s pretty hard for Hackaday to get behind that approach.

The impact assessment sounds more like advertising copy for the proposed ruling than an honest assessment, but you should give it a read because it lets you know where the commission is coming from. Reassuring is that they mention open-source software development explicitly as a good to be preserved, but their “likely social impacts” include “increased security and safety” and they conclude that there are no negative environmental impacts. What do you do when the manufacturer no longer wants to support the device? I have plenty of gear that’s no longer supported by firmware updates that is both more secure and simply not in the landfill because of open-source firmware.

Similarly, “the increased capacity of the EU to autonomously secure its products is also likely to help the citizens to better protect their information-related rights” is from a bizarro world where you can trust Xiaomi’s home-automation firmware to not phone home, but can’t trust an open-source replacement.

Public comment is still open, and isn’t limited to European citizens. As mentioned above, it might affect you even if you’re not in the EU, so feel free to make your voice heard. You have until September, and you’ll be in some great company if you register your complaints. Indeed, reading through the public comments is quite heartening: Universities, researchers, and hackers alike have brought up reasons to steer clear of the proposed approach. We hope that the commission hears us.