Non-Contact Probe Works Better With A Little More Complexity

March 29, 2022 by 5 Comments

Non-contact voltage probes have been around a while and some test equipment now has them built-in. This is one of those things that you probably don’t think about much, but surely it isn’t that hard to detect AC voltage. Turns out there are a lot of circuits floating around that can do it and [nsievers51] tried a bunch. Many didn’t work very well, but the best used a 4069 CMOS hex inverter. A dollar store flashlight provided power, a case, and an LED and the result was a good-looking and effective probe.

The circuit came from the Electronics Library website and is fairly complex for this sort of device. The CMOS inverters have a high input impedance so they pick up the weak signal. Instead of directly driving an LED, two inverters form a ring oscillator that generate pulses around 1 kHz. At that frequency, the LED appears to be on, but battery consumption is less severe. A single 2N2222-style transistor drives the LED.

We’ve seen a number of variations on this tool in the past. Many of them only use transistors.

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Converting Your Bike To Electric: Why You Should, And When You Shouldn’t

March 29, 2022 by 96 Comments

A decade ago I was lucky enough to work for an employer that offered a bicycle loan scheme to its employees, and I took the opportunity to spend on a Brompton folding bike. This London-made machine is probably one of the more efficiently folding cycles on the market, and has the useful feature of being practical for longer journeys rather than just a quick run from the train. A 3-speed hub gearbox is fine for unhurried touring, but sadly my little folder has always been a bit of a pain on the hills. Thus around the start of the pandemic I splashed out again and bought a Swytch electric upgrade kit for it, and after a few logistical and life upheavals I’ve finally fitted it to the bike. I’ve ridden a few electric bikes but never had my own, so it’s time to sit down and analyse the experience. Is an electric bike something you should have, or not?

A Box Of Bits Becomes An Electric Bike

All the parts of a Swytch kit
All the parts of a Swytch kit. From the Swytch assembly manual.

Swytch sell their kits via crowdfunding rounds, so I’d been on a waiting list for a while and got an early-bird price on my kit. It took quite a while to arrive, much longer than the expected time in mid-2020 because of the pandemic, finally being delivered some time in February last year. It came in a modestly-sized cardboard carton which would be an easy carry on the Brompton’s luggage rack, containing neatly packed a new front wheel with motor, as well as the battery and all sundry parts.

Fitting the kit shouldn’t stretch the capabilities of a Hackaday reader, with probably the trickiest part being the positioning of a Hall-effect sensor near the crank. The kit works by providing a motor assist when you pedal, so part of it is a set of magnets on a plastic disk with various attachments for different cranks and pedal sets. The Brompton front wheel is removed and its tyre and tube transferred to the Swytch one, which is then put on the bike. Once the magnet disk and Hall sensor are attached, the cables follow the existing ones and emerge at the handlebars where a sturdy bracket for the battery box is fitted. Continue reading “Converting Your Bike To Electric: Why You Should, And When You Shouldn’t” →

LED Kaleidoscope Uses Induction Power Magic

March 29, 2022 by 4 Comments

The kaleidoscope was first invented back in the early 1800s, with the curio known for showing compelling psychedelic patterns as light passes through colored glass and is reflected by mirrors in a tube. [Debra] of Geek Mom Projects recently gave the classic toy a thoroughly modern twist with her own build. (Thread Reader Link).

[Debra]’s kaleidoscope still relies on the typical mirror-tube construction to create reflections upon reflections which generate symmetrical patterns for the viewer. However, instead of colored glass beads lit by external light, she replaced these with so-called “wireless LEDs.” These little bead-like LEDs are fitted with small coils that allow them to be inductively powered without wires when they are placed in the magnetic field generated by a powered coil. Thus, [Debra]’s kaleidoscope works day or night, even in a dark room, since the light is coming from the little beady LEDs themselves.

It’s a great demonstration of wireless LED technology; there’s something almost magical about the tiny free-moving glowing beads. If you don’t want to buy them off the shelf, you can even make your own! Video after the break.

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Enter The 2022 Hackaday Prize And Help Save The World

March 29, 2022 by 7 Comments

The biggest challenge facing humanity over the next century is how to do as much or more, with less environmental impact. Reducing our collective footprint on the planet is of course not any one person’s responsibility alone, and if it’s going to require a million clever solutions to create a sustainable future, then we know just the group of hackers to get to work.

This year’s 2022 Hackaday Prize challenges you to think of big or small ways to create greener energy sources, make recycling easier, hack old devices to save them from the landfill, or build out the networks that keep our local communities together and conscious of our group effort. If you’ve got a super solar harvester, a recycling robot, or even reverse engineering tools to help combat forced technological obsolescence, we want to see your hacks. Or if you’d like, you can simply save the world in the wildcard round.

As always, courtesy of our overlords at Supplyframe and the generous sponsorship of Digikey, we’ve got tons of prize money to give out to the best projects. The top ten projects in each of five challenge rounds will receive a $500 cash prize, and five winning projects will bag from $5,000 to $50,000 in the finals in November. But you shouldn’t wait — the first round, Planet-Friendly Power, starts right now!

Get your team together, start brainstorming an idea, post it up on Hackaday.io to enter in the Prize, and you’re on your way. Independent of the judging, we’ll be looking through the field and writing up awesome projects as we find them. This is your chance to be seen, to help create a better world, and maybe even to win big.

Challenge Date The Details
Planet-Friendly Power Mar 29 – May 1 Your solution should lower the cost of clean energy, through energy harvesting and/or storage efficiency improvements.
Reuse, Recycle, Revamp May 1 – June 12 Your project facilitates recycling of material that would otherwise end up in the waste stream.
Hack it Back June 12th – July 24 Your project adds new capabilities to older electrical gear to keep it useful.
Climate Resilient Communities July 24 – Sept 4 Design devices that help communities be more resilient to weather and climate disasters and/or collect data from their environments so that they may advocate for changes in local infrastructure.
Save the World Wildcard Sept 4 – Oct 16th This is where anything goes, your designs should stand apart from the other challenges but still create a more promising future for all.

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A miniature Vectrex console being used

Finally, The Venerable Vectrex Gets A Mini Makeover

March 29, 2022 by 16 Comments

It appears that every great console is bound to get a miniature remake: we’ve had the PlayStation Classic, the Mini NES and SNES, and even a miniature Sega Genesis/Mega Drive. But one great console that was sorely missing from that list, at least according to [Brendan], was the Vectrex. So he went ahead and built a fully-functioning miniature Vectrex Console.

If the name “Vectrex” doesn’t ring a bell in your mind, you’re not alone: a commercial failure, it was quickly forgotten by most following the 1983 video game crash. But it has retained a cult status among enthusiasts due to its unique design featuring a monochrome vector monitor, onto which you can place transparent overlays to obtain a sort-of color display. Its games can now all be emulated using software like RetroPie, which is what [Brendan] chose to run on a Raspberry Pi Model 2 that he had lying around.

As for the display, he settled on a Pi-compatible 3.5″ TFT device. Hooking it up to the Pi was easy enough, but getting the image rendered in its proper portrait orientation was quite a headache, requiring endless fiddling with drivers and configuration files.

Once he got this working, [Brendan] set to work designing a miniature copy of the Vectrex’s original case. It took a few iterations and several 10-hour runs on his 3D printer before he ended up with a sturdy case that securely held the Pi and its display in place. A few more hours of printing later he also had a handheld controller, which he based on an Arduino Pro Mega. The Arduino reads out four regular pushbuttons and a joystick, and communicates with the Pi through a coiled USB cable.

The end result, as you can see in the video embedded below, is the cutest little Vectrex we’ve ever seen. It’s really the opposite of this big-screen Vectrex project. We’ve also seen a Vectrex projector, and even one with a real color monitor hacked in. Continue reading “Finally, The Venerable Vectrex Gets A Mini Makeover” →

LEGO String Winder Hints At Greater Possibilities

March 29, 2022 by 9 Comments

Unless you’re an avid fan of 1997’s box office hit Mouse Hunt, or actively working in the string industry, you probably don’t spend a lot of time thinking about how those balls of string are made. [ord] has, however, and built a tidy little winding machine that has us contemplating the possibilities of how useful LEGO machines can really be. 

The design uses a large and imposing-looking ring gear to drive a spinning arm which carries the string onto the bobbin. The bobbin itself is rotated along with the spinning arm as the hand crank that operates the machine is mechanically linked to both. As the arm and bobbin turn, string is deposited onto the bobbin, building up into a pleasing ball of string that looks just like the ones you buy at the store.

We suspect that, unless [ord] is doing some very interesting things that we haven’t seen yet, the string was probably sourced off a reel or ball anyway, and this machine just serves to demonstrate how the process works.

However, it does go to show how LEGO machines can do real work. We’d love to see LEGO put to more practical uses like winding pickups or transformers, or other jobs that are maddeningly tedious when done by hand. Video after the break.

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Raspberry Pi Creates Melody

March 28, 2022 by 2 Comments

For those who are not into prog rock in the 70s or old radio shows from the 40s, the Theremin may be an unfamiliar musical instrument. As a purely electronic device, it’s well outside the realm of conventional musical instruments. Two radio antennas detect the position of the musician’s hands to make a unique sound traditionally associated with eeriness or science fiction.

Normally a set of filters and amplifiers are used to build this instrument but this build instead replaces almost everything with a Raspberry Pi Zero 2, and instead of radio antennas to detect the position of the musician’s hands a set of two HC-SR04 distance sensors are used instead. With the processing power available from the Pi, the modernized instrument is able to output MIDI as well which makes this instrument easily able to interface with programs like GarageBand or any other MIDI-capable software.

The project build is split into two videos, the second of which is linked below. The project code is also available on the project’s GitHub page, so anyone with the Pi and other equipment available can easily start experimenting with this esoteric and often overlooked musical instrument. It’s been around for over 100 years now, and its offshoots (including this build) are as varied as the sounds they can produce.

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