This is a work in progress, capturing several observations gleaned from some of my recent experiments and projects of varying success that use ESP32 modules and run from batteries. One project in particular uses disposable AA batteries and another uses an old-school NiCad and small solar panel (it’s a wifi…
An impressively loquacious comment-spam diatribe
I have received a notable uptick in comment spam lately, despite removing the website field (the main value proposition for spammers) and requiring a CAPTCHA. Usually I let my automated spam filters just delete it all, but when I saw this particular comment in the spam folder I thought it…
Clothes Dryer Window Interlock – Edit: now with Wifi
Introduction My house was built without a penetration for the clothes dryer vent. When drying clothes, it is important to first open the window and poke the vent pipe out. Occasionally one of my housemates (or I) forget to do this, causing the laundry room to become a sauna rain indoors…
Amplifier Fan Controller
This article describes the temperature controlled fan circuit that I designed for my audio amplifier. The Amplifier A few years ago I built a new amplifier – the Ultra Low Distortion Amplifier Mk3 by Silicon Chip magazine. It’s an excellent amplifier packing 135W RMS per channel into 8Ω (200W into 4Ω) with…
Opamps
Operational amplifiers (opamps for short) are a fantastic analogue circuit building block. While they were originally used for mathematical operations (hence the name) in early analogue computers, they are now mainly used for audio applications. What is an opamp? An op-amp or operational amplifier to be exact is quite literally…
Disco Lights
What does it do? The Disco Lights project is what you get when you combine the fantastic beat detection circuitry of my ever popular beat triggered strobe light with coloured halogen lamps! In other words, four coloured lights flash in a variety of patterns in time with your music. Some…
Karaoke Circuit
What is it? The simple karaoke circuit takes a stereo line level audio signal from a CD player, mp3 player or similar and, in the case of most music recorded in the last 2 or 3 decades, significantly reduces the volume of the vocals without removing much of the accompaniment. …
Beat triggered strobe light
Due to the substantial improvements in LED technology over the years, this ancient (2005) project is outdated. High voltage Xenon flash tube based strobe lights are simply not relevant in DIY applications any more when one can now purchase LED modules really cheaply that are actually a lot brighter than tube…