Dr. Scott Baker designed and built an ETA-3400 Memory/IO accessory for the vintage Heathkit ET-3400 trainer, that is available on GitHub: I’ve always wanted one of these Heathkit microprocessor trainers, and finally one caught my eye on eBay and I pulled the trigger. The basic interaction with the trainer is through the onboard keypad and […]
Category Archives: PCBs
Custom NES cartridge – Harambe’s revenge
Troy Denton and Brad Taylor made a USB reprogrammable NES cartridge: Initially, Brad and I wanted to make a PCB that could do some very ambitious things, requiring either a very capable processor, or an FPGA device. We began down this path, but soon realized that we were biting off much more than we could […]
A self-expanding ESP32 PWM board
Eric Gunnerson writes: I’ve been working on a little ESP32 expansion board/shield for an LED project I’ve been working on. One of the nice things about the ESP32 is that it has a peripheral known as “LED control” that provides 16 independent channels of PWM for controlling LED brightness, and my project uses that capability. […]
Acorn BBC Master and electron cartridge breakout
The Acorn Master cartridge breakout board by Simon Inns: This project provides a simple breadboard adapter/breakout board for prototyping cartridges for the Acorn BBC Master and Acorn Electron 8-bit computers. The design consists of two PCBs, the first plugs into the computer’s cartridge slot and the second is designed to plug along the edge of […]
NFC antenna tuning without a VNA
Fred writes: Recently I started work on a new board. This one will be a front door entry system, so I decided to go with something that could read my NFC implant but also had a numeric keypad for the kids (and anyone else) to use. Not everyone wants to be chipped. Crazy, isn’t it? […]
Serial Star, a 4 in 1 USB serial and I2C converter
Jesus Echavarria published a new build: Here’s one of the last board I design the last year. On 2016, I develop the Dual USB Serial and I2C Converter board. Although this board works fine, it has a couple of lacks. First one, is that to use the both converters, you need two free USB ports. […]
Multislope ADC bring up (dual slope)
Nava Whiteford has been working on a Multislope ADC: I’ve been playing with a multislope ADC design. Multislope ADC are often used in high end multimeters, and as I have a mild obsession with 8.5 digit multimeters, I wanted to try making a multislope ADC. See the full post on 41J blog.
uMesh – A self-contained, battery operated ESP32 module
Jarrett published a new build: I’ve been working on an ESP32 module. Part of the problem I’ve been seeing with inexpensive IoT dev boards, is that the design around the power system hasn’t been very good. Here’s my attempt to fix that. This is a battery-ready module with a proper lithium battery charge circuit, lithium […]
6809 CPU board for the RC2014
Ben Chong posted his RC2014 6809 CPU board, that is available on github. More details on his blog.
Scott’s Z80SBC: Z80 single board computer
Dr. Scott M. Baker published a new build: When I was first getting started with electronics, wanted a Heathkit ET-3400 Microproccessor trainer, but could never afford one at the time. Eventually both I and the world moved on, to fancier more capable computers. However, I’ve still always wished I had an iconic trainer, complete with […]
Open source Agilent 53132A 53131A OCXO ultra high stability oven upgrade
Gaurav Singh made an open source 53132A OCXO Ultra stability time base, that is available on github: While i was working with my own GPSDO project. i need to have a frequency counter with descent stability so purchased my self a Agilent 53132A which is a 12 digit frequency counter, big brother to 53131A 10 […]
Twin ‘T’ CW (Morse) Practice Oscillator
Steve Smith (G0TDJ) writes, “I successfully completed the Twin ‘T’ Oscillator, original by Mike Maynard – K4ICY. It’s a great circuit and sounds really good. Much better than a raspy 555 version. Mike has been kind enough to put a link to my project on his website.” More details at www.ProjectAVR.com.
Wavecatcher
Anfractuosity published a new build: “Acoustic cryptanalysis is a type of side channel attack that exploits sounds emitted by computers or other devices” Wavecatcher is a simple PCB that makes use of a MEMS ultrasound microphone, in order to capture audio to around 80kHz, with the goal of finding interesting ultrasound sources and playing with […]
StyloCard
Stylophone business card project from mitxela.com Printed Circuit Boards as a business card are a great gimmick. I’d seen ones with USB ports etched into them, which enumerate as a keyboard and then type a person’s name or load up their website. It’s just about possible to build them cheap enough to hand out as a […]
BLE Module PCB made with silver paste/laser printer
NRF52 Bluetooth Low Energy Module PCB using laser printer/silver paste method by Rich Olson. More details at nothinglabs.com.
10MHz distribution amplifier
G4FRE built a 10MHz distribution amplifier: I have had a need for a distribution amplifier for a while now. Searching around I found the design by G4JNT in Radcom, which filled my needs. I redrew the circuit for 4 outputs and had PCBs made. (if you want one contact me!) I now have the units […]
DIY Arduino PCB Pryamiduino
A how-to on designing a DIY Arduino PCB Pryamiduino from Bald Engineer: Continuing the DIY Arduino tutorial series, this AddOhms episode shows how to create a PCB in KiCad. I make a joke that the original design was a rectangle, which I found boring and pointless. So instead, I designed a triangle to give the board […]
Small motor controller with integrated position sensor
Ben Katz writes: A while ago I added the hall effect encoder IC I’ve been using directly to the motor controller PCB. The controller sits directly on the back of the motor (with a magnet added to the motor shaft), and the phase wires solder straight in. I also have a pair of board-mounted XT30 […]
Open source 22mm diameter PCB project
An open source 22mm diameter PCB project from Concretedog, that is available on github: So I posted a while back about how I had used these 22mm pcb’s I’d made in prototyping an ematch ignitor system for use in rocketry. Although I made these stackable boards so they would fit inside a popular size of […]
DIY through hole plating of PCBs
Jan Mrázek documented his experience experimenting with DIY through-hole plating of PCBs: I’ve been thinking about though hole plating for several years. The general procedure is simple – you have to activate non-copper surfaces (make them conductive) and then you apply standard electroplating procedure. You can find many tutorials on the internet, however, most of […]