Steve showing a circuit built with spintronics blocks

Electronics Explained With Mechanical Devices

January 1, 2023 by Arya Voronova 16 Comments

It can be surprisingly hard to find decent analogies when you’re teaching electronics basics. The water flow analogy, for instance, is decent for explaining Ohm’s law, but it breaks down pretty soon thereafter.

Hydraulics aren’t as easy to set up when you want an educational toykit for your child to play with, which leaves them firmly in the thought experiment area. [Steve Mould] shows us a different take – the experimentation kit called Spintronics, which goes the mechanical way, using chains, gears, springs and to simulate the flow of current and the effect of potential differences.

Through different mechanical linkages between gears and internal constructs, you can implement batteries, capacitors, diodes, inductors, resistors, switches, transistors, and the like. The mechanical analogy is surprisingly complete. [Steve] starts by going through the ways those building blocks are turned into mechanical-gear-based elements. He then builds one circuit after another in quick succession, demonstrating just how well it maps to the day-to-day electronic concepts. Some of the examples are oscillators, high-pass filters, and amplifiers. [Steve] even manages to build a full-bridge rectifier!

In the end, he also builds a flip-flop and an XOR gate – just in case you were wondering whether you could theoretically build a computer out of these. Such a mechanical approach makes for a surprisingly complete and endearing analogy when teaching electronics, and an open-source 3D printable take on the concept would be a joy to witness.

Looking for something you could gift to a young aspiring mind? You don’t have to go store-bought – there are some impressive hackers who build educational gadgets, for you to learn from.

A DIY Pulse Tube Cryocooler In The Quest For Home-Made Liquid Nitrogen

January 1, 2023 by Maya Posch 5 Comments

What if you have a need for liquid nitrogen, but you do not wish to simply order it from a local supplier? In that case you can build your very own pulse tube cryocooler, as [Hyperspace Pirate] is in the process of doing over at YouTube. You can catch part 1 using a linear motor and part 2 using a reciprocating piston-based version also after the break. Although still very much a work-in-progress, the second version of the cryocooler managed to reduce the temperature to a chilly -75°C.

The pulse tube cryocooler is one of many types of systems used for creating a cooling effect. Commercially available refrigerators and freezers tend to use Rankine cycle coolers due to their low cost and effectiveness at (relatively) warmer temperatures. For cryogenic temperatures, Stirling engines are commonly used, although they find some use in refrigeration as well. All three share common elements, but they differ in their efficiency over a larger temperature range.

In this video series, the viewer is taken through the physics behind these coolers and the bottlenecks which prevent them from simply cooling down to zero Kelvin. Despite the deceptive simplicity of pulse tube cryocoolers — with just a single piston, a regenerator mesh, and some tubing — making them work well is an exercise in patience. We’re definitely looking forward to the future videos in this series as it develops.

Continue reading “A DIY Pulse Tube Cryocooler In The Quest For Home-Made Liquid Nitrogen” →

Raspberry Pi biosensor with screen-printed electrodes

Raspberry Pi And PpLOGGER Make A Low-Cost Chemiluminescence Detector

December 31, 2022 by Orlando Hoilett 11 Comments

[Laena] and her colleagues at the La Trobe Institute for Molecular Science in Melbourne, Australia used a Raspberry Pi to make a low-cost electrochemiluminescence (ECL) detector to measure inflammation markers, which could be used to detect cardiovascular disease or sepsis early enough to give doctors a better chance at saving a patient’s life.

ECL reactions emit light as a result of an electrically-activated chemical reaction, making them very useful for detecting biochemical markers in blood, saliva, or other biological samples. ECL setups are fundamentally fairly straightforward. The device includes a voltage reference generator to initiate the chemical reaction and a photomultiplier tube (PMT) to measure the emitted light. The PMT outputs a current which is then converted to a voltage using a transimpedance amplifier (TIA). That signal is then sampled by the DAQCplate expansion board and the live output can be viewed in ppLOGGER in real-time.

Using the RPi allowed the team to do some necessary, but pretty simple signal processing, like converting the TIA voltage back to a photocurrent and integrating the current to obtain the ECL intensities. They mention the added signal processing potential of the RPi was a huge advantage of their setup over similar devices, however, simple integration can be done pretty easily on most any microcontroller. Naturally, they compared their device to a standard ECL setup and found that the results were fairly comparable between the two instruments. Their custom device showed a slightly lower limit of detection than the standard setup.

Their device costs roughly $1756 USD in non-bulk quantities with the PMT being the majority of the cost ($1500). Even at almost $2000, their device provides more than $8000 in savings compared to ECL instruments on the market. Though cost is much more than just the bill of materials, we like seeing the community making efforts to democratize science, and [Laena] and her colleagues did just that. I wonder if they can help us figure out the venus fly trap while they’re at it?

Get To Know Touch With This Dev Board

December 31, 2022 by Jenny List 5 Comments

In the catalogue of the Chinese parts supplier LCSC can be found many parts not available from American or European suppliers, and thus anyone who wants to evaluate them can find themselves at a disadvantage. [Sleepy Pony Labs] had just such a part catch their eye, the Sam&Wing AI08 8 channel capacitive touch controller. How to evaluate a chip with little information? Design a dev board, of course!

The chip tested is part of a family all providing similar functionality, but with a variety of interface options. The part tested has eight touch inputs and a BCD output. Said output is used to feed a 74 series decoder chip and drive some LEDs. The touch pads were designed with reference to a Microchip application note which incidentally makes for fascinating reading on the subject as it covers far more than just simple touch buttons.

Whether or not you’ll need this touch chip is a matter for your own designs, however, what this project demonstrates is that with the ready availability of cheap custom PCBs and unexpected parts it’s not beyond reason to create boards just for evaluation purposes.

Perhaps the subject of a previous Hackaday piece would have found this board useful.

In Praise Of “Just Because” Hacks

December 31, 2022 by Elliot Williams 25 Comments

Sometimes you pick a project because the world needs it to be done. Or maybe you or a friend need it. Or maybe you don’t really need it, but it fulfills a longstanding dream. In my mind, the last stop before you reach “why am I doing this” is the “just because” hack.

The ideal “just because” hack is limited in scope. You don’t want to spend years on a whimsical project, and because of this a “just because” hack isn’t usually motivating enough to keep you going that long anyway, except for the tenacious few. A “just because” doesn’t necessarily have to be an easy win, but it makes sense for you to see your way out before you get in too deep.

I’m not sure if it’s the Baader-Meinhof phenomenon or not, but in the last week or so in the Hackaday universe, a lot of people have been singing the praises of “just because” hacks. (Check out this one discussion, for instance.) Mostly, it’s a combination of them turning out better than initially thought, or it’s about the learning that came along for the ride. Of course, many of them spin off into longer, serious projects even if they didn’t start that way.

Not everything in life can be frivolous, of course. But that makes the “just because” hack that much sweeter, and you should try to make mental room for them if you can. When the stakes are low, creativity can be high. You might still want to impose a deadline, lest you fall into eternal yak shaving, but take it easy. You don’t need a justification all the time: the journey can be the destination.

Screenshot of the framework-built app, showing it running through Firefox

Turn A Webpage Into A Desktop App With Gluon

December 30, 2022 by Arya Voronova 39 Comments

Electron is software for running web-written apps in the same way as native ones, and has gotten plenty of bad press for its RAM appetite around these parts. But while the execution might leave something to be desired, the concept itself is quite solid — if you’ve already got code written for the web, a quick and easy way to bring it over to the desktop would be very valuable.

Which is why [CanadaHonk] is building a framework called Gluon, which aims to turn your web pages into desktop apps with little to no effort. We’ve seen their work a few months ago with the OpenASAR project, hacking the Discord desktop app to speed it up. Drawing from that experience, Gluon is built to be lean – with apps having low RAM and storage footprints, lightning-speed build times, and a no-nonsense API.

One of the coolest parts is that it’s able to use your system-installed browser, and not a bundled-in one like Electron. Firefox support is firmly on the roadmap, too, currently in experimental stage. Linux support is being worked on as well — the framework is Windows-born, but that’s to change. There’s also room to innovate; [CanadaHonk] recently added a hibernation feature with aggressive RAM and CPU footprint reduction when the app is minimized, something that other frameworks like this aren’t known for.

If you want to write user-facing software, JavaScript’s a decent language, and quite a few of you are going to be familiar with it. You aren’t limited to the software side of the tech world, either — tools like WebUSB and WebSerial will let you write a user interface for a board that you’ve just developed. For instance, here’s a WebSerial-based oscilloscope, a nifty serial terminal, or a hacker conference badge programming toolkit. For all that browsers have gotten wrong, they certainly don’t seem to become less abundant, and if that means you can quickly develop cross-platform hardware-facing apps, it’s certainly a useful addition to one’s toolkit.

A laptop with a desk phone and a 3D-printed acoustic coupler next to it

Acoustic Coupler Gets You Online Through Any Desk Phone

December 30, 2022 by Robin Kearey 48 Comments

Up until the mid-1980s, connecting a computer to a phone line was tricky: many phone companies didn’t allow the connection of unlicensed equipment to their network, and even if they did, you might still find yourself blocked by a lack of standardized connectors. A simple workaround for all this was an acoustic coupler, a device that played your modem’s sounds directly into a phone’s receiver without any electrical connection. Modem speeds were slow anyway, so the limited bandwidth inherent in such a system was not much of a problem.

Nowadays it’s easier to find an internet connection than a phone line in many places, but if you’re stuck in an ancient hotel in the middle of nowhere you might just find [GusGorman]’s modern take on the acoustic coupler useful. The basic design is quite simple: it’s a 3D-printed box with two cups that fit a typical phone handset and a space to put a USB speaker and microphone. Thanks to minimodem it’s easy to set up a connection with any other computer equipped with a phone connection.

Continue reading “Acoustic Coupler Gets You Online Through Any Desk Phone” →