DIY Electronics and Hardware

GitHub Link

A tech tinkerer has shared the full plans and resources necessary to build a compact desktop laser engraver. All the resources are available on GitHub, including the components list, 3D printer files, firmware, drivers, and software. Moreover, project creator Elias55745 is selling a fully assembled ‘mini laser printer’ created using these plans for just $64. They also intend to sell everything you need as a kit for self-assembly. However, the store is undergoing maintenance at the time of writing, so the shopping cart isn’t working, and you may see prices in Yen (I did).

GH: https://github.com/El-EnderJ/NeoCalculator

Graphics calculators are one of those strange technological cul-de-sacs. They rely on outdated technology and should not be nearly as expensive as they are, but market effects somehow keep prices well over $100 to this day. Given that fact, you might like to check out an open-source solution instead.

NumOS comes to us from [El-EnderJ]. It’s a scientific and graphic calculator system built to run on the ESP32-S3 with an ILI9341 screen. It’s intended to rival calculators like the Casio fx-991EX ClassWiz and the TI-84 Plus CE in terms of functionality. To that end, it has a full computer algebra system and a custom math engine to do all the heavy lifting a graphic calculator is expected to do, like symbolic differentiation and integration. It also has a Natural V.P.A.M-like display—if you’re unfamiliar with Casio’s terminology, it basically means things like fractions and integrals are rendered as you’d write them on paper rather than in uglier simplified symbology.

Remember tamagotchi? Those little digital pets really took the world by storm for a while, and they're still going to this day. However, unlike the early days of the digital pet, we now have the resources and the know-how to make our own tamagotchis. We can even make them open-source so people can tweak them the way they want.

If you have an ESP32 sitting around and you think it'd be better served as a cute little creature that you need to take care of, then you can do a lot worse than check out this adorable project. While it's still a work-in-progress, it's already at the point where you can take care of a cute critter in your spare time. And when you're busy. And just about all the time.

I didn't set out to avoid official ESP32 developer boards. In the beginning, the DevKitC was my default. It's the board that shows up in every tutorial, the one Espressif clearly intended as a starting point. So I bought a couple, wired them up on breadboards, and started building projects. But somewhere along the way, I realized that what I was buying weren't always official boards anyway, and as I branched out to things like the XIAO line from Seeed Studio, the gap between "official reference design" and "tool I actually want to use" became hard to ignore.

To be clear, it wasn't the price that was the problem for me. Third-party boards from reputable vendors aren't typically cheaper, and in most cases they're actually more expensive. What you're paying for is the stuff around the chip: battery charging, better connectors, basically just a form factor that doesn't fight you.

None of this should come across as being anti Espressif. Espressif makes fantastic chips, and their official boards serve an important purpose. However, these reference designs are for, well, reference. Third-party boards often feel a lot closer to being a finished developer tool rather than a physical manifestation of documentation that an official Espressif board tends to feel like. The base boards are great, but for any project you want to build, a third-party board is likely to suit your needs a whole lot better.

Ever wanted to build custom battery packs for electric bikes, solar power banks, or RC projects but found commercial spot welders too expensive? I've got the perfect solution! In this Instructable, I'll show you how to build a powerful yet affordable battery spot welder from scratch. This isn't just another simple project—it's a professional-grade tool that uses the classic NE555 timer and parallel MOSFETs to deliver precise, controlled welding pulses.

Introduction

BBTrack is a hardware-hacking project that repurposes the optical trackpad from a BlackBerry 8520 mobile phone and transforms it into a compact USB HID pointing device for modern computers. The goal of the project is to retain the nostalgic charm of classic BlackBerry hardware while giving it a new and highly practical role — this time as a tiny, hackable pointing interface.

At the core of BBTrack is the RP2040 microcontroller, chosen for its flexibility, performance, and strong ecosystem support. On the firmware side, the device is powered by QMK, enabling robust USB HID functionality and making customization straightforward for makers and keyboard enthusiasts.

GitHub Link https://github.com/nmur/M5Stack-CompositeTestPatternGenerator

GitHub Link: https://github.com/C4KEW4LK/rpi_usb_ip_display/tree/main

Ever wanted to just plug something in and conveniently read the hostname and IP addresses of a headless board like a Raspberry Pi? Chances are, a free USB port is more accessible than digging up a monitor and keyboard, and that’s where [C4KEW4LK]’s rpi_usb_ip_display comes in. Plug it into a free USB port, and a few moments later, read the built-in display. Handy!

The device is an RP2350 board and a 1.47″ Waveshare LCD, with a simple 3D-printed enclosure. It displays hostname, WiFi interface, Ethernet interface, and whatever others it can identify. There isn’t even a button to push; just plug it in and let it run.

YT Guide: https://www.youtube.com/watch?v=iUDOLJ1Ki84

The usual input device for playing a synthesizer is the good old piano keyboard. However, you don’t have to stick to such pedestrian interfaces when making music. [Daisy] has a fun build that shows us how to put together a ribbon synth that makes wonderful little noises.

Naturally, the heart of the build is a ribbon potentiometer (also known as soft pots). It’s essentially a touch sensitive strip that changes in resistance depending on where you touch it. You can slide your finger up and down to vary the output continuously; in musical contexts, they can behave rather like a fretless instrument. [Daisy] employs one of these potentiometers in such a role by hooking it up to a Daisy Seed microcontroller board, which reads it with an analog-to-digital converter (ADC). The resistance values are used to vary the pitch of a dual-saw synthesizer programmed in the plugdata framework.

If you’ve got an old black and white TV, it’s probably not useful for much. There are precious few analog broadcasters left in the world and black and white isn’t that fun to watch, anyway. However, with a little work, you could repurpose that old tube as a clock, as [mircemk] demonstrates.

The build is based around an Arduino Nano R3. This isn’t a particularly powerful microcontroller board, but it’s good enough to run the classic TVOut library. This library lets you generate composite video on an Atmel AVR microcontroller with an absolute minimum of supporting circuitry. [mircemk] paired the Arduino with a DS3231 real-time clock, and whipped up code to display the time and date on the composite video output. He then also demonstrates how to hack the signal into an old TV that doesn’t have a specific input for composite signals.

Instructables link

Designed by Nova Radio Labs in the US, the Novaduino Environmental Sensor Kit is an Arduino-programmable air quality and weather monitoring solution built around the company’s own Novaduino Display Module. It provides VOCs, eCO₂, temperature, humidity, and barometric pressure data in real time, making it ideal for Smart Home experiments, classroom projects, or hobby weather-station builds.

The kit integrates a Sciosense ENS160 air-quality sensor and Bosch BME280 environmental sensor connected via Qwiic, which measures TVOCs, eCO₂, temperature, humidity, and pressure with an on-device AQI indicator. It includes the Novaduino display PCBA, 2.4-inch IPS touchscreen, buttons, rotary encoder, Feather M0 Express or RP2040 module support, headers, mechanical hardware, and optional 3D-printable enclosures (STL/F3D/STP). Designed for learning soldering, assembly, and Arduino programming, the kit is uncalibrated and intended for educational and experimental use only.

A project I keep thinking about for my kitchen when I get it done up is an approximate clock display, so an eink display showing something like

https://kenlim.github.io/pyWordyClock/

Or similar. I guess the latter running on a Pi of some description.

I would be new to most of this, can anyone point me to a good way of getting started?

Over on YouTube [DENKI OTAKU] runs us through how a 4-pin MOSFET works and what the extra Kelvin source pin does.

A typical MOSFET might come in a 3-pin TO-247 package, but there are 4-pin variants which include an extra pin for the Kelvin source, also known as source sense. These 4-pin packages are known as TO-247-4. The fourth pin provides an additional source for gate current return which can in turn lessen the effect of parasitic inductance on the gate-source when switching current, particularly at high speed.