Instant Macropad: Just Add QMK

August 20, 2025 by Al Williams 2 Comments

I recently picked up one of those cheap macropads (and wrote about it, of course). It is surprisingly handy and quite inexpensive. But I felt bad about buying it. Something like that should be easy to build yourself. People build keyboards all the time now, and with a small number of keys, you don’t even have to scan a matrix. Just use an I/O pin per switch.

The macropad had some wacky software on it that, luckily, people have replaced with open-source alternatives. But if I were going to roll my own, it would be smart to use something like QMK, just like a big keyboard. But that made me wonder, how much trouble it would be to set up QMK for a simple project. Spoiler: It was pretty easy.

The Hardware

Simple badge or prototype macropad? Why not both?

Since I just wanted to experiment, I was tempted to jam some switches in a breadboard along with a Raspberry Pi Pico. But then I remembered the “simple badge” project I had up on a nearby shelf. It is simplicity itself: an RP2040-Plus (you could just use a regular Pi Pico) and a small add-on board with a switch “joystick,” four buttons, and a small display. You don’t really need the Plus for this project since, unlike the badge, it doesn’t need a battery. The USB cable will power the device and carry keyboard (or even mouse) commands back to the computer.

Practical? No. But it would be easy enough to wire up any kind of switches you like. I didn’t use the display, so there would be no reason to wire one up if you were trying to make a useful copy of this project.

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Project Scribe thermal printer printing out a receipt

Project Scribe: Receipts For Life

July 20, 2025 by John Elliot V 16 Comments

Here’s a fun project. Over on their YouTube page [Urban Circles] introduces Project Scribe.

The idea behind this project is that you can print out little life “receipts”. Notes, jokes, thoughts, anecdotes, memories. These little paper mementos have a physical reality that goes beyond their informational content. You can cut them up, organize them, scribble on them, highlight them, stick them on the wall, or in a scrapbook. The whole idea of the project is to help you make easier and better decisions every day by nudging you in the direction of being more mindful of where you’ve been and where you’re going.

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Volume Controller Rejects Skeumorphism, Embraces The Physical

July 9, 2025 by Tyler August 34 Comments

The volume slider on our virtual desktops is a skeuomorphic callback to the volume sliders on professional audio equipment on actual, physical desktops. [Maker Vibe] decided that this skeuomorphism was so last century, and made himself a physical audio control box for his PC.

Since he has three audio outputs he needs to consider, the peripheral he creates could conceivably be called a fader. It certainly has that look, anyway: each output is controlled by a volume slider — connected to a linear potentiometer — and a mute button. Seeing a linear potentiometer used for volume control threw us for a second, until we remembered this was for the computer’s volume control, not an actual volume control circuit. The computer’s volume slider already does the logarithmic conversion. A Seeed Studio Xiao ESP32S3 lives at the heart of this thing, emulating a Bluetooth gamepad using a library by LemmingDev. A trio of LEDs round out the electronics to provide an indicator for which audio channels are muted or active.

Those Bluetooth signals are interpreted by a Python script feeding a software called Voicmeeter Banana, because [Maker Vibe] uses Windows, and Redmond’s finest operating system doesn’t expose audio controls in an easily-accessible way. Voicmeeter Banana (and its attendant Python script) takes care of telling Windows what to do.

The whole setup lives on [Maker Vibe]’s desk in a handsome 3D printed box. He used a Circuit vinyl cutter to cut out masks so he could airbrush different colours onto the print after sanding down the layer lines. That’s another one for the archive of how to make front panels.

If volume sliders aren’t doing it for you, perhaps you’d prefer to control your audio with a conductor’s baton.

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Smallest Gaming Mouse Has Crazy Fast Polling Rate And Resolution

July 2, 2025 by Lewin Day 11 Comments

[juskim] wanted to build a tiny mouse, but it couldn’t just be any mouse. It had to be a high-tech gaming mouse that could compete with the best on raw performance. The results are impressive, even if the final build is perhaps less than ideal for pro-level gameplay.

The build riffs on an earlier build from [juskim] that used little more than a PCB and a 3D-printed housing to make a barebones skeleton mouse. However, this one ups the sophistication level. At the heart of the build is the nRF54L15 microcontroller, which is paired with a PAW3395 mouse sensor which is commonly used in high-end gaming mice. It offers resolution up to 26K DPI for accurate tracking, speeds up to 650 ips, and 8 kHz sampling rates. Long story short, if you want fine twitch control, this is the sensor you’re looking for. The sensor and microcontroller are laced together on a custom PCB with a couple of buttons, a battery, and a charging circuit, and installed in a barebones 3D-printed housing to make the final build as small as possible.

The only real thing letting the design down is the mouse’s key feature—the size. There’s very little body to grab on to and it’s hard to imagine being able to play most fast-paced games at a high level with such a tiny device. Nevertheless, the specs are hardcore and capable, even if the enclosure isn’t.

[juskim] loves building tiny peripherals; we’ve featured his fine work before, too. Video after the break.

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Open-Source Knob Packed With Precision

June 28, 2025 by Matt Varian 63 Comments

The world of custom mechanical keyboards is vibrant, with new designs emerging weekly. However, keyboards are just one way we interact with computers. Ploopy, an open-source hardware company, focuses on innovative user interface devices. Recently, [Colin] from Ploopy introduced their latest creation: the Ploopy Knob, a compact and thoughtfully designed control device.

At first glance, the Ploopy Knob’s low-profile design may seem unassuming. Housed in a 3D-printed enclosure roughly the size of a large wristwatch, it contains a custom PCB powered by a USB-C connection. At its core, an RP2040 chip runs QMK firmware, enabling users to easily customize the knob’s functions.

The knob’s smooth rotation is achieved through a 6705ZZ bearing, which connects the top and bottom halves and spans nearly the device’s full width to eliminate wobble. Unlike traditional designs, the Ploopy Knob uses no mechanical encoder or potentiometer shaft. Instead, an AS5600 magnetic encoder detects movement with remarkable precision. This 12-bit rotary encoder can sense rotations as fine as 0.088 degrees, offering 4096 distinct positions for highly accurate control.

True to Ploopy’s philosophy, the Knob is fully open-source. On its GitHub Page, you’ll find everything from 3D-printed case files to RP2040 firmware, along with detailed guides for assembly and programming. This transparency empowers users to modify and build their own versions. Thanks to [Colin] for sharing this innovative device—we’re excited to see more open-source hardware from Ploopy. For those curious about other unique human-machine interfaces, check out our coverage of similar projects. Ploopy also has designs for trackballs (jump up a level on GitHub and you’ll see they have many interesting designs).

Making GameCube Keyboard Controller Work With Animal Crossing

June 26, 2025 by John Elliot V 2 Comments

[Hunter Irving] is a talented hacker with a wicked sense of humor, and he has written in to let us know about his latest project which is to make a GameCube keyboard controller work with Animal Crossing.

This project began simply enough but got very complicated in short order. Initially the goal was to get the GameCube keyboard controller integrated with the game Animal Crossing. The GameCube keyboard controller is a genuine part manufactured and sold by Nintendo but the game Animal Crossing isn’t compatible with this controller. Rather, Animal Crossing has an on-screen keyboard which players can use with a standard controller. [Hunter] found this frustrating to use so he created an adapter which would intercept the keyboard controller protocol and replace it with equivalent “keypresses” from an emulated standard controller.

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Split Keyboard Uses No PCB

June 18, 2025 by Al Williams 18 Comments

When [daniely101] wanted a split keyboard, he decided to build his own. It wound up costing $25 to create a wireless board with no custom PCB required. Each half has its own microcontroller, and the whole thing connects via Bluetooth. While we don’t mind making a PCB, we can appreciate that you could change your mind easily with this wiring scheme.

The 3D printed case holds the keys, and then it is just a matter of carefully soldering the keys to the microcontrollers. Of course, each side also has to have its own battery. The ZMK firmware is split in half, one part for each side of the keyboard. The nRF52840 CPUs have plenty of wireless connectivity. The keys are set in rows and columns, so the amount of soldering back to the controller is manageable.

While we applaud the wireless design, it does seem odd that you have to charge both halves and turn them on and off separately. But that’s the nice thing about a design like this — you could modify the design to not have a split. Or, you could allow one flexible wire pair to run across for power. Of course, you could modify the layout, including adding or deleting keys.

You might consider adding a pointing device. At least you don’t have to pull out a saw.

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