Op-Amp Challenge: A Logic-Free BCD

Of digital electronics, a wise man once said that “Every idiot can count to one.” Truer words have rarely been spoken, because at the end of the day, every digital circuit is really jus…

Tiny PCB Banishes Soldering Fumes, Automatically

A fan to remove fumes is a handy thing to have when soldering, even better is a fan furnished with a filter. Better still is a fan that activates only when the iron is in use, turning off when the …

A Cassette Interface For A 6502 Breadboard Computer, Kansas City-Style

It’s been a long time since computer hobbyists stored their programs and data on cassette tapes. But because floppy drives were expensive peripherals and hard drives were still a long way fro…

The No-MCU Fan Controller

The default for any control project here in 2019 was to reach for a microcontroller. Such are their low cost and ubiquity that they can be used to replicate what might once have needed some extra c…

Homebrew Circuit Explores The Mysteries Of Analog-to-Digital Conversion

When it comes to getting signals from an analog world into our computers, most of us don’t give much thought to how the hardware that does the job works. But as it turns out, there are a numb…