December 2021

This month’s highlights

Easy-to-build Digital AM/FM/SW Receiver

Using a cheap and readily available BK1198 digital radio chip, this design only needs an Arduino Nano and a handful of discrete components to produce a complete digital radio receiver covering AM, FM and SW bands. The radio also sports a backlit 16×2 LCD display. A smaller version is also described that drives an earpiece instead. Source code is available for free download to subscribers.

  Uses a mixture of surface mount and through-hole components and good soldering skills are required to complete this project successfully.

Balanced Input and Attenuator for the USB Codec (Part 1)

The SuperCodec USB Sound Card described in the three previous issues has a superlative specification and can form the core of a high-performance audio measurement system. This month we offer a compact balanced input attenuator that fits into the same case as the SuperCodec. Together they form a potent recording and/ or measurement system. The article also explains the merits of balanced audio signals. The circuit is described this month with construction details following in Part 2.

Mini Digital Volt/ Amp Panel Meters

There are many low-cost digital panel meters (DPMs) sold online which can display voltage or current simultaneously on dual seven-segment displays. This feature article takes a look at some typical ones that you will find on sale on the web, outlining how to hook them up and utilise their features.

KickStart – Part 6: Exploring Direct Digital Synthesis (DDS)

KickStart is a series that fast-tracks constructors using readily available, low-cost components and devices to solve a wide range of problems in the shortest possible time. This month’s instalment investigates the field of Direct Digital Synthesis (DDS) and introduces the AD9833 DDS chip before offering more go-to resources for the constructor to investigate.

Also in this issue:

  • The Fox Report – smart watches aren’t as smart as they claim to be, says Barry Fox.
  • This month’s Tekkiepix – an early 1950s video recorder designed by the BBC
  • Techno Talk- a new design of battery that is powered by human bodily fluids!
  • Net Work – how Amazon Smile donates to your charity at no extra cost to you, the Rolls Royce electric plane and more trends and developments.
  • Max’s Cool Beans – more merriment involving flashing LEDs and robotics
  • Circuit Surgery – Op.amp logarithmic and exponential amplifiers (Part 1)
  • Audio Out – Analogue Vocoder (Part 2). Continuing the design of a classic vocal effects system
  • Electronic Building Blocks – a self-contained programmable stepper motor controller.

In next month’s issue:

Vintage Battery Radio Li-ion Power Supply; MiniHEART beat simulator; Balanced Input & Attenuator for the USB SuperCodec (Part 2); Busy Loo Door Warning. Contents may be subject to last minute change.

December 2021 files for download -


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