Rotary encoders, done properly

Rotary encoders, in the most recognisable form, are mechanical devices that look a bit like potentiometers, and are often used in their place. Some audio gear uses them, and are recognisable as volume controls with regular bumps or clicks as they turn. They are also used in mechanical trackballs and mice, as well as lots of other applications that require accurate rotational sensing.

In hobbyist applications, they are handy for all sorts of things - potentiometer replacements, up/down switching, etc. Using them with AVRs, PICs and Arduinos is quite common and they are easily available.

Open Bench Logic Sniffer "case"

The Open Bench Logic Analyser is a cheap ($50) open source logic analyser board, which talks a standard (ie open) protocol to a PC client. Very useful!

As it's just a bare board, lots of people have designed and build their own case for it. Many are built with 3d printers and related methods. I did one too, but instead of going the real high tech route, I just used a slab of 6mm Perspex, cut into 3 pieces and with slots milled for the PCB to slide into.

Check it out:

A Nixie Tube clock

This is a repost from my old mothballed blog, this project still gets interest.


For the last couple of years I've been keen to build a nixie tube clock.

Nixie tubes are those early (1950's-70s) display tubes often used in industrial and commercial applications, before the advent of LEDs and LCDs. They novelty and attractiveness led me to finally wanting to build one, but it wasn't until after I'd moved back to Sydney from Holland that I was able to get around to it.

My clock is built entirely from scratch, and is based on 4000 series logic ICs for the actual clock counting, and 74141 chips for the tube drivers. It's self contained, requiring only a 12v AC/DC plug pack to run. It features 6 digits (HH.MM.SS), buttons for setting hours, minutes, and zero seconds, 1 minute per year accuracy, supercap power backup and an LDR to shut the display off after a predetermined period of darkness (switch overridable).