The Air Multiplier Fan Principle, Applied To A Jet Engine

January 28, 2022 by Jenny List 26 Comments

Many readers will be familiar with the Dyson Air Multiplier, an ingenious bladeless fan design in which a compressor pushes jets of air from the inside edge of a large ring. This fast-moving air draws the surrounding air through the ring, giving the effect of a large conventional fan without any visible moving parts and in a small package. It’s left to [Integza] to take this idea and see it as the compressor for a jet engine, and though the prototype you see in the video below is fragile and prone to melting, it shows some promise.

His design copies the layout of a Dyson with the compressor underneath the ring, with a gas injector and igniter immediately above it. The burning gas-air mixture passes through the jets and draws the extra air through the ring, eventually forming a roaring jet engine flame exhaust behind it. Unfortunately the choice of 3D print for the prototype leads to very short run times before melting, but it’s possible to see it working during that brief window. Future work will involve a non-combustible construction, but his early efforts were unsatisfactory.

It’s clear that he hasn’t created the equivalent of a conventional turbojet. Since it appears that its operation happens when the flame has passed into the center of the ring, it has more in common with a ramjet that gains its required air velocity with the help of extra energy from an external compressor. Whether he’s created an interesting toy or a useful idea remains to be answered, but it’s certainly an entertaining video to watch.

Meanwhile, this isn’t the first project we’ve seen inspired by the Air Multiplier.

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Acoustic Switching Transistors: A New Kind Of Electronics?

January 28, 2022 by Al Williams 7 Comments

Have you ever heard of topological insulators? These are exotic materials where electricity flows only on the surface with very little loss. Now, according to IEEE Spectrum, scientists at Harvard have used the same concept to create a transistor for sound waves and it may be a new branch of electronics. The actual paper is available if you want some light reading.

Apparently, topological insulators protect electrons moving along their surfaces and edges, something that won the 2016 Nobel Prize in Physics. Photons can also be protected topologically so they move with very little loss across the materials. Making electrons flow in this manner is an attractive proposition, but there are challenges, especially when creating a device that can switch the flow of electrons on and off as you might with a transistor in and out of saturation. Sound waves, however, are much easier to work with.

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Long Range Burglar Alarm Relies On LoRa Modules

January 28, 2022 by Lewin Day 15 Comments

[Elite Worm] had a problem; there had been two minor burglaries from a storage unit. The unit had thick concrete walls, cellular signal was poor down there, and permanent wiring wasn’t possible. He thus set about working on a burglar alarm that would fit his unique requirements.

An ESP32 is the heart of the operation, paired with a long-range LoRa radio module running at 868 MHz. This lower frequency has much better penetration when it comes to thick walls compared to higher-frequency technologies like 4G, 5G or WiFi. With a little coil antenna sticking out the top of the 3D-printed enclosure, the device was readily able to communicate back to [Elite Worm] when the storage unit was accessed illegitimately.

With an eye to security, the device doesn’t just warn of door open events. If signal is lost from the remote transmitter in the storage unit, perhaps due to an advanced adversary cutting the power, the alarm will also be raised. There’s still some work to be done on the transmitter side, though, as [Elite Worm] needs to make sure the door sensor is reliable under all conditions.

Many put their hardware skills to work in service of security, and we regularly see proprietary alarm systems modified by enterprising hackers. Video after the break.

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3D Printed Jig Makes Custom Springs A Snap

January 28, 2022 by Tom Nardi 13 Comments

We’ve often heard it said that springs come in in all shapes and sizes…except for the one you need. In light of this, the hardware hacker would do well to keep the tools and knowledge required to make a custom spring close at hand when building something that moves. Luckily, all it really take is some stiff metal wire, a rod, and patience.

Unless you’ve got a 3D printer, that is. In which case, we’d suggest you print out this very clever “Spring Factory” designed by [Vincent Baillet]. The simple tool, consisting of just two parts, makes it easier and faster to make consistent DIY springs when compared to traditional methods. Rather than trying to eyeball the spacing of the coil as you wind the wire around the mandrel, this design does it for you.

As seen in the video, springs made with this tool look very professional. Not only does the threaded mandrel keep the spacing between coils even, it also makes sure all the springs you produce are identical. This can be especially important with projects that need to use multiple matching springs. [Vincent] says his handy tool works with piano wire from 0.8 to 1.2 mm, and slightly thicker if plain steel.

Of course, the obvious flaw in a tool like this is that it can only be used to make springs of a specific diameter. Changing the length is easy enough, just use more or less wire. But to make a thinner or thicker spring, you’d need a different size of mandrel. It seems that [Vincent] has only released the gadget in this approximately 9 mm diameter so far, but here’s hoping a few more sizes get added to the mix before too long.

Looking for something a bit more advanced? This Arduino-powered wire bender is capable of making some very impressive custom springs, among other things.

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Custom Piano Tickles The Ivories

January 28, 2022 by Bryan Cockfield 6 Comments

The core ethos of “hacking” is usually interpreted as modifying something for a use that it wasn’t originally built for. Plenty of builds are modifications or improvements on existing technology, but sometimes that just isn’t enough. Sometimes we have to go all the way down and build something completely from scratch, and [Balthasar]’s recent piano-like musical instrument fits squarely into this category.

This electronic keyboard is completely designed and built from scratch, including the structure of the instrument and the keys themselves. [Balthasar] made each one by hand out of wood and then built an action mechanism for them to register presses. While they don’t detect velocity or pressure, the instrument is capable of defining the waveform and envelope for any note, is able to play multiple notes per key, and is able to change individual octaves. This is thanks to a custom 6×12 matrix connected to a STM32 microcontroller. Part of the reason [Balthasar] chose this microcontroller is that it can do some of the calculations needed to produce music in a single clock cycle, which is an impressive and under-reported feature for the platform.

With everything built and wired together, the keyboard is shockingly versatile. With the custom matrix it is easy to switch individual octaves on the piano to any range programmable, making the 61-key piano capable of sounding like a full 88-key piano. Any sound can be programmed in as well, further increasing its versatility, which is all the more impressive for being built from the ground up. While this build focuses more on the electronics of a keyboard, we have seen other builds which replicate the physical action of a traditional acoustic piano as well.

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Shelf Actualization

January 28, 2022 by Al Williams 54 Comments

If you are old enough, you may remember that, for a time, almost every year was the year that home video was going to take off. Except it never was, until VHS tape machines appeared. We saw something similar with personal computers. Nowadays, we keep hearing about the home robot, but it never seems to fully materialize or catch on. If you think about it, it could be a problem of expectations.

What we all want is C3PO or Rosie the Robot that can do all the things we don’t want to do. What we usually get is something far less than that. You either get something hideously expensive that does a few tasks or something cheap that is little more than a toy.

Labrador Systems is trying to hit the middle ground. While no one would confuse their Caddie and Retriever robots with C3PO, they are useful but also simple, presumably to keep the cost down which are expected to cost about $1,500. The robots have been described as “self-driving shelves.” You can watch a video about the devices below.

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Hackaday Podcast 153: A 555 Teardown To Die For, Tetrabyte Is Not A Typo, DIY Injection Molding, And Using All The Parts Of The Trash Printer

January 28, 2022 by Tom Nardi No comments

Join Hackaday Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi on another whirlwind tour of the week’s top stories, hacks, and projects. We start off with some breaking Linux security news, and then marvel over impeccably designed pieces of hardware ranging from a thrifty Z table for the K40 laser cutter to a powerful homebrew injection molding rig. The finer technical points of a USB device that only stores 4 bytes at a time will be discussed, and after taking an interactive tour through the internals of the 555 timer, we come away even more impressed by the iconic 50 year old chip. We’ll wrap things up by speculating wildly about all the bad things that can happen to floating solar panels, and then recite some poetry that you can compile into a functional computer program should you feel so inclined.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct Download (58 MB)