Everything for Electronics


Take the Z80 Challenge

This project started out as a challenge to myself: Could I cram a full-featured Z80 microcomputer using DIP packages onto an ExpressPCB MiniBoard (3.8” by 2.5”)? Here’s what happened.

Build a $6 Desk Mic

I certainly didn’t need another desk mic, but the prospect of building one from a $1 LED lamp and a spare mic cartridge was a project I could not pass up.

Build an Instant Heart Pulse Sensor

In about 10 minutes and for about $6, you can display the blood flow through your finger. From this measurement, you can extract your heart rate, check for arrhythmia, and even modulate a red light to pulsate with your heart rate. Here’s how.

Build a Lunch Box Jukebox

The Lunch Box Jukebox is a compilation of various projects to make a compact portable music, video, and game entertainment device with the Raspberry Pi Zero at the heart of the Jukebox Internet radio.

Updating a General-purpose Programming System

Twenty years ago, I published an article in Nuts & Volts about designing a general-purpose programming system: the LP120. I’ve used the LP120 heavily for the last 20 years to support my eight-bit design hobby. It now has uploadable drivers and programming modules for many eight-bit micros, EPROMs, and GALs. However, things have changed since 2000. Back then, few microcontrollers had more than 4K bytes of program memory. Now, eight-bit PICs have up to 64K words of memory. Clearly an update to the LP120 was called for.

Build a Freezer Alarm Circuit

I’m not sure if it’s absent mindedness or just old age, but sometimes I’ll forget to close the food freezer lid after shopping for groceries. With food prices seemingly going up every three days, there’s really no good time to lose a pile of food because of a simple mistake. This article describes my solution to the freezer problem.

Build the FLiPVox Laser Theremin

In my previous Theremin article, I described the first of my laser Theremin projects: the LASERVox. This is a simple-to-construct Theremin-like device that acts as a MIDI controller for a synthesizer. In that article, I discussed the possibility of a more analog style laser Theremin that has its own built-in synthesizer or pitch generator. That’s the topic of this article! We’ll build the FLiPVox: a continuous pitch laser Theremin with its own mini synthesizer.

Pinochle — Social Distance Style

I belong to a group who enthusiastically plays Pinochle once a week. Unfortunately, with the present circumstance of social distancing during the COVID-19 pandemic, we have been deprived of our weekly get together. So, with today’s technology and an introduction to the virtual conferencing provided by Zoom, I decided to see if we could play Pinochle online.

An Altair Clone: Then and Now

When I read the article “Build a Pocket-Sized Altair Computer” by David Hunter on building an Altair clone, I was reminded that I too had designed an Altair clone, but I built mine in 1977. Mine required seven boards in a 19” rack. This article details the resources I had then in a comparison of what resources are available today. I’ll also describe how I designed and built my clone.

Can’t Keyboard? Use Morse Code Instead

A few months ago, I accepted a challenge: Design a way for people who can’t easily use a keyboard to create text for applications such as Word, OpenOffice, eBay, or Google via Morse code. It takes only two fingers to create them, and learning to send Morse code proves easier than learning to receive it, which requires much practice. See how I used a $10 Cypress Semiconductor CY8CKIT-059 MCU board to mimic a USB keyboard but without software drivers, code libraries, or special USB-interface ICs.