January 2022

Vintage Battery Radio Li-ion Power Supply

Vintage radio “A” and “B” batteries have been unavailable for quite some time. To fill this gap, this project is a compact and easy to build replacement using Li-ion or LiPo cells that can generate both the A (1.2 – 2.5V) and B (24 – 135V) supplies for most battery valve (vacuum tube) sets. It suits a wide range of HT voltages and generates virtually no EMI. It runs from two or four cells and has built in over-discharge protection.

The MiniHeart

This mini module produces an authentic-sounding heartbeat on a miniature speaker that may have soothing effects on newborn children or pets, helping to improve sleep patterns. Or it could be incorporated into some toys. Using a PIC12F617 microcontroller and a miniature class-D amplifier chip, the project has adjustable volume and heart rate, and a flashing LED synchronised with the heartbeat. Powered by two AAA cells, it has an adjustable timeout from two minutes to four hours.

Includes surface mount components, good soldering skills are needed to complete this project successfully.

Balanced Input and Attenuator for the USB SuperCodec – Part 2

This add-on board for the USB SuperCodec provides two balanced inputs with four attenuation options: 0dB, 10dB, 20dB and 40dB.  This month, the practical aspects of construction are given along with detailed advice and photographs to help ensure assembly and installation are successful.

PIC n’ Mix (Part 9) – PIC 18F Development Board

This month our PICmicro expert Mike Hibbett takes the next steps in creating the PIC18F development board, adding a variety of mono and colour LCDs.

Also in this issue:

• The Fox Report – Barry Fox updates us with news of the Rampion 2 wind farm and how its detractors might have got things wrong
• Techno Talk – how protein ‘nanowires’ form a naturally occurring ‘wood wide web’
• Net Work – new top-up devices for EVs, NIO’s Power Swap system, forthcoming Ora electric cars, Rolls-Royce’s new nuclear power plant and more!
• Flowcode Graphical Programming – an overview of the Flowcode IDE and programming with RedBoard and PICs (Part 1)
• Max’s Cool Beans – more miscellaneous musings from Max
• Circuit Surgery – Part 2 of an in-depth analysis of op.amp logarithmic and exponential amplifiers
• Audio Out – Analogue Vocoder Part 3: Driver Amplifier
• Make It with Micromite – Part 32: Using iButtons with the Micromite

In next month’s issue:

Arduino-based adjustable power supply; Battery Multi Logger; Electronic wind chimes; Mini Digital AC Panel Meters.