Retro Style VFO Has Single-Digit Parts Count

December 2, 2025 by Tyler August 2 Comments

Not every project has to be complicated– reinventing the wheel has its place, but sometimes you find a module or two that does exactly what you want, and the project is more than halfway done. That the kind of project [mircemk]’s Simple Retro Style VFO is — it’s a variable frequency oscillator for HAM and other use, built with just a couple of modules.

Strictly speaking, this is all you need for the project.

The modules in question are the SI5351 Clock Generator module, which is a handy bit of kit with its own crystal reference and PLL to generate frequencies up to 150 MHz, and the Elecrow CrowPanel 1.28inch-HMI ESP32 Rotary Display. The ESP32 in the CrowPanel controls the SI5351 module via I2C; control is via the rest of the CrowPanel module. This Rotary Display is a circular touchscreen surrounded by a rotary display, so [mircmk] has all the inputs he needs to control the VFO.

To round out the parts count, he adds an appropriate connector, plus a power switch, red LED and a lithium battery. One could include a battery charger module as well, but [mircmk] didn’t have one on hand. Even if he had, that still keeps the parts count well inside the single digits. If you like video, we’ve embedded his about the project below; if not the write up on Hackaday.io is upto [mircmk]’s typical standard.

People have been using the SI5351 to make VFOs for years now, but the addition of the round display makes for a delightfully retro presentation.

Thanks to [mircmk] for the tip.

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Making A Laptop With A Mechanical Keyboard

September 16, 2025 by Fenix Guthrie 16 Comments

A laptop is one of the greatest tools at the disposal of a hacker. They come in all manner of shapes and sizes with all manner of features. But perhaps the greatest limit held by all laptops is their chiclet keyboard. While certainly serviceable, a proper mechanical keyboard will always reign supreme, which is why [flurples] built a laptop around a mechanical keyboard.

Such a keyboard could not fit inside any normal laptop, so a custom machined case was in order. The starting point was a standard Framework Laptop 13. Its open source documentation certainly helped the project, but numerous parts such as the audio board and fingerprint sensor are not documented making for a long and tedious process. But the resulting machined aluminum case looks at least as good as a stock Framework chassis, all be it, quite a bit thicker.

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Faux Potentiometers Use Magnets, No Contacts

September 6, 2025 by Al Williams 22 Comments

Ever tear open a potentiometer? If you haven’t, you can still probably guess what’s inside. A streak of resistive material with some kind of contact that moves across it as you rotate the shaft, right? Usually, you’d be right, but [T. K. Hareedran] writes about a different kind of pot: ones that use magnetic sensing.

Why mess with something simple? Simplicity has its price. Traditional units may not be very accurate, can be prone to temperature and contamination effects, and the contact will eventually wear out the resistive strip inside. However, we were a little curious about how a magnetic potentiometer could offer a resistive output. The answer? It doesn’t.

Really, these would be better described as rotary encoders with a voltage output. They aren’t really potentiometers. The SK22B mentioned in the article, for example, requires a 5 V input and outputs somewhere between 10% and 90% of that voltage on the ersatz wiper pin.

That makes the devices much easier to puzzle out. The linearity of a device like that is better than a real pot, and, of course, the life expectancy is greatly increased. On the other hand, we’d rather get one with quadrature or I2C output and read it digitally, but if you need a voltage, these devices are certainly an option.

[T. K.] goes on to show how he fabricated his own non-contact sensor using photosensors and a gray-coded wheel with a single track. You do need to be careful about where you position the sensors, though.

Could you make a real non-contact resistive pot? Seems like you could get close with an FET output stage, but it wouldn’t be as generally applicable as a good old-fashioned smear of carbon. If you have a better idea, drop it in the comments or build it and give us a tip.

Want a 20A-capable device? Build it. Want to see how we like to read encoders?

Turn A Mouse Into An Analogue Tuning Knob

September 27, 2024 by Jenny List 4 Comments

The software defined radio has opened up unimaginable uses of the radio spectrum for radio enthusiasts, but it’s fair to say that there’s one useful feature of an old-fashioned radio they lack when used via a computer. We’re talking of course about the tuning knob, because it represents possibly the most intuitive way to move across the bands. Never fear though, because [mircemk] has a solution. He’s converted a mouse into a tuning dial.

The scroll wheel on a mouse is nothing more than a rotary encoder, and can easily be used as a sort of tuning knob. Replacing it with a better encoder gives it a much better feel, so that’s what he’s done. An enclosure has the guts of a mouse, with the front-mounted encoder wired into where the scroll wheel would have been. The result, for a relatively small amount of work, is a tuning knob, and a peripheral we’re guessing could also have a lot of uses beyond software defined radio.

It’s not the first knob we’ve seen, for that you might want to start with the wonderfully named Tiny Knob, but it’s quite possibly one of the simplest to build. We like it.

Retro Inspired Cyberdeck Scrolls Around Cyberspace

July 25, 2024 by Tom Nardi 24 Comments

It’s difficult to nail down exactly what counts as a “real” cyberdeck in this brave new era of bespoke computing. But at the minimum, most in the community would agree that a proper deck should have a non-traditional form factor, and be designed to meet the unique needs of the builder. If you’re looking for a fantastic example of both concepts, check out the Cyberdore 2064 from [Tommi L].

At first glance the 3D printed enclosure of the Cyberdore looks a bit like a Speak & Spell, but it’s really more of an amalgamation of everything that made 1980s computers so unique. You’ve got the vents, the chunky switches, the undersized display, and of course, the handle. The case might have been extruded in 2024, but it’s doing a fantastic impression of a piece of tech from 40 years ago.

One of the key external features of the Cyberdore 2064 is the side-mounted rotary encoder that allows for smoothly scrolling through online feeds (such as your favorite hardware hacking site) or long documents. The cheap and easy to work with KY-040 encoder has been converted to a USB input device by way of a Pi Pico, and has been paired with an over-sized 3D printed knob that really makes this build stand out — not only visually, but in terms of usability. These cyberdeck builds often rely on touch screens for input, but we always appreciate a physical interface.

Under the hood you’ve got a Raspberry Pi Zero and an 18650 cell to keep the whole thing running while on the go. Though the Zero is certainly showing its age compared to the more modern variants of the Pi, for a device like this, raw computing power isn’t really the driving concern. A mechanical keyboard usually rounds out these cyberdeck builds, but in this case, [Tommi] went with a fairly common Rii 518BT portable board that’s been skillfully integrated into the front of the Cyberdore.

All of the STL files necessary to print out your own Cyberdore 2064 are available on Printables, and while [Tommi] didn’t exactly provide build instructions, the write-up provides plenty of information to get you started.

So is it just us, or does looking at Cyberdore 2064 make you think it’s time for another Hackaday Cyberdeck Challenge?

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Foot Keyboard

October 25, 2023 by Kristina Panos 12 Comments

[crispernaki]’s opening comments to this VCR head scroll wheel project lament that overall technical details aren’t “complex, ground-breaking, or even exciting.” Since when does that matter? The point is that not only did the thing finally, eventually get built, it gets daily use and it sparks joy in its owner.

This feel-good story is one of procrastination, laziness, and one aha! moment, and it’s roughly twelve years in the making. Inspired by an Instructable from long ago, [crispernaki] ran straight to the thrift store to get a VCR and take it apart.

The original plan was to just reuse the VCR head’s PCB and hide it in an enclosure, and then figure out way to block and unblock the path between an IR emitter/receiver pair. After many disemboweled mice and fruitless attempt, the project was once again shelved.

But then, [crispernaki] remembered the magnetic rotary encoder demo board that was just sitting around, along with various microcontrollers and Altoids tins. And it all quickly came together with a Teensy 2.0 and some bits and bobs, including a magnet glued on the shaft of the VCR head. A chip on the demo board does all the heavy lifting, and of course, the Teensy does the work of emulating an HID.

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A view of the inside of a car, with drivers wheel on the left and control panel in the middle, with red LED light displayed in the floor area under the drivers wheel and passenger side.

Bass Reactive LEDs For Your Car

April 25, 2023 by Abe Connelly 32 Comments

[Stephen Carey] wanted to spruce up his car with sound reactive LEDs but couldn’t quite find the right project online. Instead, he wound up assembling a custom bass reactive LED display using an ESP32.

The entirety of the build is minimal, consisting of a GY-MAX4466 electret microphone module, a KY-040 encoder for some user control and an ESP32 attached to a Neopixel strip. The only additional electronic parts are some passive resistors to limit current on the data lines and a capacitor for power line noise suppression. [Stephen] uses various enclosures from Thingiverse for the microphone, rotary encoder and ESP32 box to make sure all the modules are protected and accessible.

The magic, of course, is in the software, with the CircuitPythyon ulab library used to do the heavy lifting of creating the spectrogram and frequency filtering. [Stephen] has made the code is available on GitHub for those wanting to take a closer look.

It wasn’t very long ago that sound reactive LEDs used to be a heavy lift, requiring optimized FFT libraries or specialized components to do the spectrogram. With faster and cheaper microcontroller boards, we’re seeing many great projects, like the sensory bridge or Raspberry Pi driven LED spectrogram, that can now take spectrograms and Fourier transform calculations as basic infrastructure to build on top of them. We’re happy to see [Stephen] leverage the ESP32’s speed and various circuit Python libraries to create a very cool LED car hack.

Video after the break!

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