Misc Hacks

4032 Articles

Not A Pot, Not An Encoder: Exploring Synchros For Rotational Sensing

February 1, 2023 by 25 Comments

We’re all familiar with getting feedback from a rotating shaft, for which we usually employ a potentiometer or encoder. But there’s another device that, while less well-known, has some advantages that just might make it worth figuring out how to include it in hobbyist projects: the synchro.

If you’ve never heard of a synchro, don’t feel bad; as [Glen Akins] explains, it’s an expensive bit of kit most commonly found in avionics gear. It’s in effect a set of coaxial transformers with a three-phase stator coil and a single-phase rotor. When excited by an AC reference voltage, the voltage induced on the rotor coil is proportional to the cosine of the angle between the rotor and stator. It seems simple enough, but the reality is that synchros present some interfacing challenges.

[Glen] chose a surplus altitude alert indicator for his experiments, a formidable-looking piece of avionics. Also formidable was the bench full of electronics needed to drive and decode the synchro inside it — a 26-volt 400-Hz AC reference voltage generator, an industrial data acquisition module to digitize the synchro output, and an ESP32 dev board with a little OLED display to show the results. And those are impressive; as seen in the video below, the whole setup is capable of detecting tenth-of-a-degree differences in rotation.

The blog post has a wealth of detail on using synchros, as does this Retrotechtacular piece from our own [Al Williams]. Are they practical for general hobbyist use? Probably not, but it’s still cool to see them put to use.

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The Voice Of ChatGPT Is Now On The Air

January 28, 2023 by 39 Comments

AIs can now apparently carry on a passable conversation, depending on what you classify as passable conversation. The quality of your local pub’s banter aside, an AI stuck in a text box doesn’t have much of a living quality. human. An AI that holds a conversation aloud, though, is another thing entirely. [William Franzin] has whipped up just that on amateur radio.  (Video, embedded below.)

The concept is straightforward, if convoluted. A DSTAR digital voice transmission is received, which is then transcoded to regular digital audio. The audio then goes through a voice recognition engine, and that is used as a question for a ChatGPT AI. The AI’s output is then fed to a text-to-speech engine, and it speaks back with its own voice over the airwaves.

[William] demonstrates the system, keying up a transmitter to ask the AI how to get an amateur radio licence. He gets a pretty comprehensive reply in return.

The result is that radio amateurs can call in to ChatGPT with questions, and can receive actual spoken responses from the AI. We can imagine within the next month, AIs will be chatting it up all over the airwaves with similar setups. After all, a few robots could only add more diversity to the already rich and varied ham radio community. Video after the break.

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Hackaday.io Low-Power Challenge Begins Today

January 24, 2023 by 23 Comments

How low can you go? The 2023 Hackaday.io Low-Power Challenge is about doing the most with the least juice – bang for the power-budget buck, if you get our drift. And with three $150 gift certificates from Digi-Key on the line, you’ll be able to keep your projects going forever. The Challenge runs until March 21st, but with low-power, the devil is often in the details, so get started today!

More and more projects need to run on their own power, and more often than not, that means getting by without access to a wall plug. This contest is to encourage your designs that run on solar, small batteries, and generally energy harvested from wherever you can get it. But the power generation mechanism is taking the back seat here – we want to see what you can do with a few good electrons. Surprise us with your maximum minimalism!

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Retro Gadgets: Tired Of The Beatles On 8 Track? Try The Police

January 18, 2023 by 48 Comments

In the 1970s, 8-track audio players were very popular, especially in cars. For a couple of bucks, you could have the latest album, and you didn’t have to flip the tape in the middle of a drive like you did with a cassette. We’ve seen plenty of 8-tracks and most of us a certain age have even owned a few players. But we couldn’t find anyone who would admit to owning the Bearcat 8 Track Scanner, as seen in the 1979 Popular Electronics ad below.

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Clever Mechanism Makes A Linear Control From A Rotary Hall Sensor

January 9, 2023 by 81 Comments

Every once in a while we stumble across something so simple yet so clever that we just have to call it out. This custom linear Hall effect sensor is a perfect example of this.

By way of backstory, [Nixieguy], aka [The Electronic Mercenary], offers up a relatable tale — in the market for suitable hardware to make the game Star Citizen more enjoyable, and finding the current commercial joystick offerings somewhat wanting, he decided to roll his own controllers. This resulted in the need for a linear sensor 100 mm in length, the specs for which — absolute sensing, no brushes or encoders, easily sourced parts — precluded most of the available commercial options, like linear pots. What to do?

The solution [Nixieguy] settled on was to use a Hall effect sensor and a diametrally magnetized neodymium ring magnet. The magnet is rotated through 180 degrees by a twisted aluminum bar, which is supported in a frame by bearings. A low-friction slider with a slot captures the bar; moving the slider along the length of the control rotates the bar, which rotates the magnet, which allows the Hall sensor to measure the angle of the magnetic field. Genius!

The parts for the prototype sensor are all made from 0.8-mm aluminum sheet stock and bent to shape. The video below shows the action better than words can describe it, and judging by the oscilloscope trace, the output of the sensor is pretty smooth. There’s clearly a long way to go to tighten things up, but the basic mechanism looks like a clear win to us.

Hats off to [Nixieguy] for this one, which we’ll surely be following for more developments. In the meantime, if you need to brush up on the Hall effect, [Al Williams] did a nice piece on that a while back.

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DIYson Lamp Hides Cables Between The Seams

January 2, 2023 by 52 Comments

[Steven Bennett] is so fond of Dyson’s new Lightcycle lamp that he’s decided to clone his own version in the spirit of the original. Dyson, however, knows what makes their lamp so special — so much that they patented their technique for tucking away the power wiring. Undaunted, [Steven]’s latest challenge has been to create a cable management solution that captures the elegance of the original without making a flat-out duplicate.

[Steven]’s latest update starts with the details of the original model’s patent. In a nutshell, Dyson’s elegance comes from both a flat cable (a flex PCB, perhaps?) and a magnetic interface that transfers power between the two primary structural beams. The latter half discusses [Steven]’s alternate solution: a miniature drag chain that can be 3D printed to arbitrary lengths. Like the flat flexible cable, this cable rides in the groove of the lamp’s two structural beams; but unlike the original, it spools outwards into a hoop on one end of its travel length. Overall [Steven] is quite happy with this result, and we think this solution gives the lamp a charm that’s distinctly original.

Capturing the design essence doesn’t just stop at wire management though. Have a look at some previous video logs in the series to get a sense of some of the other challenges faced in both heat dissipation and mechanical feel.

Wire management, when done well, scratches a design itch somewhere in the back of our heads. If you’re curious for more cable management solutions, have a look at some of these other tricks that use tape measure or involve a DIY coiling method.

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A model train car carrying a camera

2022 FPV Contest: Get The Train Driver’s View In Your N-Scale Railway

December 28, 2022 by 23 Comments

Model railroaders typically observe their project from high above. It would be neat to see what the world looks like to the residents of your little town, but getting down to their point of view is difficult, especially if you’re working in one of the smaller scales. For those working in the N scale, there’s now an easy way of observing your project as the train driver would see it: [Vassily98] managed to squeeze a wireless camera into an N-scale railcar.

The main challenge here was the extremely limited space available: the track in N-scale layouts is 9 mm wide, meaning that the whole system had to fit in just 23 x 20 mm2, the frontal area of a typical train car. One of the few cameras that fit within that profile was the RunCam Nano 4, which [Vassily98] connected to an ultra-tiny Team BlackSheep 5.8 GHz video transmitter.

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