Matchbox Transceiver Pushes The Spy Radio Concept To Its Limits

May 9, 2024 by Dan Maloney 23 Comments

The Altoids tin has long been the enclosure of choice for those seeking to show off their miniaturization chops. This is especially true for amateur radio homebrewers — you really have to know what you’re doing to stuff a complete radio in a tiny tin. But when you can build an entire 80-meter transceiver in a matchbox, that’s a whole other level of DIY prowess.

It’s no surprise that this one comes to us from [Helge Fykse (LA6NCA)], who has used the aforementioned Altoids tin to build an impressive range of “spy radios” in both vacuum tube and solid-state versions. He wisely chose solid-state for the matchbox version of the transceiver, using just three transistors and a dual op-amp in a DIP-8 package. There’s also an RF mixer in an SMD package; [Helge] doesn’t specify the parts, but it looks like it might be from Mini-Circuits. Everything is mounted dead bug style on tiny pieces of copper-clad board that get soldered to a board just the right size to fit in a matchbox.

A 9 volt battery, riding in a separate matchbox, powers the rig. As do the earbud and tiny Morse key. That doesn’t detract from the build at all, and neither does the fact that the half-wave dipole antenna is disguised as a roll of fishing line. [Helge]’s demo of the radio is impressive too. The antenna is set up very low to the ground to take advantage of near vertical incidence skywave (NVIS) propagation, which tends to direct signals straight up into the ionosphere and scatter them almost directly back down. This allows for medium-range contacts like [Helge]’s 239 km contact in the video below.

Banging out Morse with no sidetone was a challenge, but it’s a small price to pay for such a cool build. We’re not sure how much smaller [Helge] can go, but we’re eager to see him try.

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The Best-Sounding Walnut You’ll Hear Today

November 2, 2023 by Kristina Panos 16 Comments

Do you ever find yourself eating walnuts and think, this would make a great enclosure for something like a Bluetooth speaker? That seems to be exactly what happened to [Penguin DIY].

In the mesmerizing video after the break, you’ll see [Penguin DIY] do what seems to be impossible. They start with a tiny 5 V power bank module which is still not small enough to fit, so they remove all the components and dead-bug them back together.

This is really just the beginning. There of course has to be a female USB of some type, so [Penguin DIY] Dremels out the perfect little slot for it.

They did manage to stack and fit a MH-MH18 Bluetooth audio module and an HXJ8002 mini audio amplifier module in the walnut, but of course, it took a lot of fiddly wiring to extend the LEDs and wire them up.

Then in the other half of the shell went the 4Ω 2 W mini speaker. [Penguin DIY] of course drilled a ton of little holes in the shell for the sound to come through. Also on this side are three tiny switches for play/pause and previous and next track, and the latter two can be long pressed to control the volume. Definitely check this out after the break.

Do the notifications of your Bluetooth speaker annoy you? There’s a hack for that.

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Circuit Sculpture Hack Chat

November 4, 2019 by Dan Maloney 7 Comments

Join us on Wednesday, November 6 at noon Pacific for the Circuit Sculpture Hack Chat with Mohit Bhoite!

For all the effort engineers put into electronic design, very few people ever get to appreciate it. All the hard work that goes into laying out a good PCB and carefully selecting just the right components is hidden the moment the board is slipped into an enclosure, only to be interacted with again through a user interface that gets all the credit for the look and feel of the product.

And yet there are some who design circuits purely as works of art. They may do something interesting or useful, but function is generally secondary to form for these circuit sculptors. Often consisting of skeletons of brass wire bent at precise angles to form intricate structures, circuit sculptures are the zen garden of electronic design: they’re where the designer turns to quiet the madness of making deadlines and meeting specs by focusing on the beauty of components themselves and putting them on display for all to enjoy.

By day, our host Mohit designs and builds hardware at Particle. By night, however, the wires and pliers come out, and he makes circuit sculptures that come alive. Check out his portfolio; you won’t be disappointed. This Hack Chat will be your chance to find out everything that goes into making these sculptures. Find out where Mohit gets his inspiration, learn his secrets for such precise, satisfyingly crisp wire-bending, and see what it takes to turn silicon into art.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, November 6 at 12:00 PM Pacific time. If time zones have got you down, 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. Continue reading “Circuit Sculpture Hack Chat” →

DIY Clapper Lets You Pick Your Components

October 6, 2019 by Al Williams 4 Comments

One thing that always means the end of the year is close is the reappearance of TV ads for “The Clapper.” After all, who needs home automation when you can clap on and clap off? While we’re partial to our usual home automation solutions, [Utsource123] shows us that building a clapper can be a fun and easy project using several similar circuits. One with a few transistors and another one with a 555 because, after all, what can’t a 555 do?

Of course, these circuits usually have a microphone. We were trying to think of how you could make a sound-sensitive element out of common parts. After all, you don’t care about the fidelity of the microphone pickup, just that it hears a loud noise. The circuits are about what you’d expect. The transistor version uses one to amplify the microphone and another to switch on the LED. You’d need a bit more to trigger a relay. The 555 uses an even simpler preamp transistor as a trigger.

While we aren’t bowled over with the idea of a clapper, we imagine these circuits aren’t far removed from the ones you buy in stores. For about $16 you also get enough switching to handle a simple AC load, though. Maybe Alexa and Google should allow making clapping a wake up word?

This is sure simpler than the last clapper clone we saw. Then there’s the deluxe DIY version.

Dead Bug Arduino Is Lively And Shield-Compatible

June 9, 2019 by Brian McEvoy 22 Comments

Microcontroller demo boards such as the Arduino UNO are ubiquitous on Hackaday as the brains of many a project which inevitably does something impressive or unusual. Sometime someone builds a particularly tiny demo board, or an impressively large one. In the case of the board featured here, the Arduino is a gorgeous labor of love which can’t really be called a board since there is no PCB. Instead of the traditional fiberglass, [Jiří Praus] formed brass bars into the circuitry and held it together with solder.

This kind of dedication to a project leaves an impression. His notes show he saw the barest way to operate an ATMega328, built it, tested, and moved on to the power supply to make it self-sustaining, then onto the communication circuit, and finally the lights. The video below shows a fully-functional Arduino happily running the blink program. He plans to encase the brass portion in resin to toughen it up and presumably keep every bump from causing a short circuit. The components are in the same position due to a custom jig which means a standard shield will fit right into place.

The Arduino started far less flashy yet nearly as fragile, and it has grown. And shrunk.

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Help For High-Frequency Hobbyists

October 5, 2018 by Brian McEvoy 21 Comments

Dead-bug circuit building is not a pretty affair, but hey, function over form. We usually make them because we don’t have a copper circuit board available or the duty of making one at home is not worth the efforts and chemical stains.

[Robert Melville and Alaina G. Levine] bring to light a compromise for high-frequency prototypes which uses the typical FR4 blank circuit board, but no etching chemicals. The problem with high-frequency radio is that building a circuit on a breadboard will not work because there is too much added inductance and capacitance from the wiring that will wreak havoc on the whole circuit. The solution is not new, build your radio module on a circuit board by constructing “lands” over a conductive ground plane, where components can be isolated on the same unetched board.

All right, sometimes dead-bug circuits capture an aesthetic all their own, especially when they look like this and they do allow for a darned small package for one-off designs.

Minimal Blinky Project Makes The Chip The Circuit Board

September 25, 2018 by Dan Maloney 16 Comments

We’ve got a thing for projects that have no real practical value but instead seek to answer a simple yet fundamental question: I wonder if I can do that? This dead-bug style 555 blinky light is one of those projects, undertaken just to see how small a circuit can be. Pretty small, as it turns out, and we bet it can get even smaller.

[Danko]’s minimal circuit is about as small as possible for the DIP version of the venerable 555 chip. The BOM is stripped to the bone: just the chip, three resistors, a capacitor, and an LED. All the discrete components are SMDs in 0805. The chip’s leads are bent around the package to form connections, and the SMDs bridge those “traces” to complete the circuit. [Danko] shows the build in step-by-step detail in the video below. There’s some fairly fine work here, but we can’t help wondering just how far down the scale this could be pushed. We know someone’s made a smaller blinky using a tiny microcontroller, but we’d love to see this tried with the BGA version of the chip which is only 1.4 mm on a side.

Cheers to [Danko] for trying this out and having some fun with an old chip. He seems to have a bit of a thing for the 555; check out this cute robot sculpture that’s built around the chip.

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