Adaptive Keyboards & Writing Technologies For One-Handed Users

June 15, 2025 by 12 Comments

After having been involved in an accident, [Kurt Kohlstedt] suffered peripheral neuropathy due to severe damage to his right brachial plexus — the network of nerves that ultimately control the shoulder, arm, and hand. This resulted in numbness and paralysis in his right shoulder and arm, with the prognosis being a partial recovery at best. As a writer, this meant facing the most visceral fear possible of writing long-form content no longer being possible. While searching for solutions, [Kurt] looked at various options, including speech-to-text (STT), before focusing on single-handed keyboard options. Continue reading “Adaptive Keyboards & Writing Technologies For One-Handed Users” →

The PCB Router You Wish You Had Made

June 14, 2025 by 41 Comments

The advent of cheap and accessible one-off PCB production has been one of the pivotal moments for electronic experimenters during the last couple of decades. Perhaps a few still etch their own boards, but many hobbiest were happy to put away their ferric chloride. There’s another way to make PCBs, though, which is to mill them. [Tom Nixon] has made a small CNC mill for that purpose, and it’s rather beautiful.

In operation it’s a conventional XYZ mechanism, with a belt drive for the X and Y and a lead screw for the Z axis. The frame is made from aluminium extrusion, and the incidental parts such as the belt tensioners are 3D printed. The write-up is very comprehensive, and takes the reader through all the stages of construction. The brains of the outfit is a Creality 3D printer controller, but he acknowledges that it’s not the best for the job.

It’s certainly not the first PCB router we’ve seen, but it may be one of the nicer ones. If you make a PCB this way, you might like to give it professional-looking solder mask with a laser.

A black PCB is shown, with an Arduino Nano mounted in the bottom left corner. The rest of the space on the PCB is used up by ten DIP integrated circuits and a few resistors and diodes. Several black and red wires connect different parts of the PCB.

Meowsic Keyboard MIDI Adapter Aims For Purrfection

June 14, 2025 by 3 Comments

Both small children and cats have a certain tendency to make loud noises at inopportune times, but what if there were a way to combine these auditory effects? This seems to have been the reasoning behind the creation of the Meowsic keyboard, a children’s keyboard that renders notes as cats’ meows. [Steve Gilissen], an appreciator of unusual electronic instruments, discovered that while there had been projects that turned the Meowsic keyboard into a MIDI output device, no one had yet added MIDI input to it, which of course spurred the creation of his Meowsic MIDI adapter.

The switches in the keys of the original keyboard form a matrix of rows and columns, so that creating a connection between a particular row and column plays a certain note. [Steve]’s plan was to have a microcontroller read MIDI input, then connect the appropriate row and column to play the desired note. The first step was to use a small length of wire to connect rows and columns, thus manually mapping connections to notes. After this tedious step, he designed a PCB that hosts an Arduino Nano to accept input, two MCP23017 GPIO expanders to give it enough outputs, and CD4066BE CMOS switches to trigger the connections.
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Laptop Brick Is Brought Back From The Brink

June 14, 2025 by 9 Comments

We’ve all been there. [Kasyan TV] had a universal adapter for a used laptop, and though it worked for a long time, it finally failed. Can it be fixed? Of course, it can, but it is up to you if it is worth it or not. You can find [Kasyan’s] teardown and repair in the video below.

Inside the unit, there were a surprising number of components crammed into a small area. The brick also had power factor correction. The first step, of course, was to map out the actual circuit topology.

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LED Probe

LED Probe: A Smart, Simple Solution For Testing LEDs

June 14, 2025 by 13 Comments

If you’ve worked on a project with small LEDs, you know the frustration of determining their polarity. This ingenious LED Probe from [David] packs a lot of useful features into a simple, easy-to-implement circuit.

Most multimeters have a diode test function that can be used to check LEDs; however, this goes a step further. Not only will the probe light up an LED, it will light up no matter which side of the LED the leads are touching. A  Red/Green LED on the probe will indicate if the probe tip is on the anode or cathode.

The probe is powered by a single CR2032 battery, and you may notice there’s no on/off switch. That’s because the probe enters a very low-current sleep mode between uses. The testing intelligence is handled by either an ATtiny85 or, in the newest version, an ATtiny202, though the basic concept and design are compatible with several other chips. All the design files for the PCB, the ATtiny code, a parts list, and a detailed explanation of how it works are available on [David]’s site, so be sure to check them out. Once you build one of these probes, you’ll want something to test it on, so explore some of the LED projects we’ve featured in the past.

Upgrading An Old Espresso Machine

June 14, 2025 by 25 Comments

The Francis! Francis! X1 espresso machine in its assembled state. (Credit: Samuel Leeuwenburg)

Recently, [Samuel Leeuwenburg] got his paws on a Francis! Francis! X1 (yes, that’s the name) espresso machine. This is the espresso machine that is mostly famous for having been in a lot of big TV shows in the 1990s. In the early 2000s, the X1 even became a pretty good espresso machine after the manufacturer did some more tinkering with it, including changing the boiler material, upgrading the pump, etc.

In the case of the second-hand, but rarely used, machine that [Samuel] got, the machine still looked pretty good, but its performance was pretty abysmal. After popping the machine open the boiler turned out to be pretty much full of scale. Rather than just cleaning it, the boiler was upgraded to a brass version for better heat retention and other perks.

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Wood bent into a spiral

Make Magical-Looking Furniture With Kerf Bend Wizard

June 14, 2025 by 26 Comments

The intersection between “woodworkers” and “programmers” is not a densely populated part of the Venn diagram, but [Michael Schiebler] is there with his Kerf Bend Wizard to help us make wood twist and bend like magic.

Kerf bending is a fine technique we have covered before: by cutting away material on the inside face of a piece of wood, you create an area weak enough to allow for bending. The question becomes: how much wood do I remove? And where? That’s where Kerf Bend Wizard comes to the rescue.

More after the break…

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