August 2020

Micromite LCD BackPack V3

This upgrade has all the features of the V1 and V2 BackPacks, plus it supports both 2.8-inch and 3.5-inch touchscreen displays. Also included are optional extra memory, temperature, humidity and pressure sensors, an RTC, IR receiver and more.

Steering Wheel Audio Button to InfraRed Adaptor

If you upgrade the radio or infotainment head in a car having push-button steering wheel controls, those controls may no longer work because aftermarket head units do not support them. This new adaptor lets you use many of those handy controls with a wide range of aftermarket head units. Suitable for resistance-switching type controls only, not intended for digital types. (Vehicle testing instructions are included in the article.) Easy to build, PIC micro based design. (Next month, we offer a car ‘radio head’ dimmer unit.)

Junk Mail Repeller

This fun project is an adaptable sound recorder/ playback module that can store up to 11 seconds of audio. It uses a very cheap ISD1820 recorder module which is readily available on the Internet, complete with microphone and speaker. This article explores its operation and shows one use, triggering a voice clip when activated by a letterbox!

Class-D Stereo Plus Subwoofer Amplifier

Unbelievable but true, this project uses a ready-assembled 2+1 50W amplifier module for about £7.50. Based on the latest Texas Instruments TPA3116D2 power IC, the boards come ready-made and will benefit from some modifications that just require some straightforward soldering. A Bluetooth-enabled version is examined as well.

Also in this issue:

• The Fox Report – Barry Fox on how woeful tech sector PR avoids scrutiny from journalists
• Techno Talk – Mark Nelson harks back to the era when mobile phone communications were foreseen
• Net Work – the rise of video conferencing, Yubico 2FA security keys and more SpaceX news
• Circuit Surgery – our in-house expert Ian Bell gives an in-depth overview of LTspice sources
• Audio Out – Part 1 of a low-noise Theremin Power Supply
• Make It with Micromite (Part 19):  programming the Micromite Robot Buggy LED ‘eyes’
• Practically Speaking – Introduction to surface-mount technology (Part 3) – the evolution of SMDs and first steps in utilising them
• Max’s Cool Beans – next stages in building a NeoPixel-powered array of 144 ping-pong balls (why wouldn’t you?)
• Electronic Building Blocks – trying a 1-15V battery capacity tester sourced from the web.

Next month

An Ultrabrite LED Pushbike Light, The Micromite Explore-28, and three popular stepper motor drivers are described.