October 2024

More pages – an 80 page bumper issue for you to enjoy!

500W Monobloc Class-D Amplifier

Building a 500W+ audio amplifier isn’t a trivial task, either in terms of complexity or cost, so we hit upon the idea of utilising ready-made modules and power supplies to keep the challenge manageable, and also keep costs reasonable. After careful consideration of product specs and availability, we chose a particular pre-built Class-D mono amplifier along with a specific 1kW soft-switching power supply that we confidently felt would do the job nicely.

During development we went to great lengths to satisfy ourselves about specification, performance and, above all, safety. Some alternative suggestions are also described for the benefit of experimenters. All aspects are detailed including the necessity and design of a fan-cooled ventilation system.

This article describes in full detail how to build a 500W Class-D amplifier using some off-the-shelf modules. The project will be just the thing to challenge advanced constructors looking for a high-power, if not exactly hi-fi, amplifier that can safely be constructed at an affordable price.

  There are some major hazard warnings that all constructors must observe.

Programming Adaptors for SMD devices

If you’re ever faced with the job of programming a QFP (quad flat-pack) SMD microcontroller then you’ll be interested in this adaptor which will help tackle a multitude of package types. This special article describes how to program such devices, and other types besides, out-of-circuit using a number of reconfigurable programming jigs. They’re inexpensive and easy to make.

2m VHF FM Test Signal Generator

This project for radio enthusiasts used an AD9834 DDS (direct digital synthesis) chip in an unusual way. It produces signals in the 2m band (144-148MHz) even though that’s well beyond its 80MHz oscillator frequency. The project can produce a CW signal at three different levels and there’s an option to add frequency modulation as well. Constructors will find it easy to align the output filter, and everything else is digitally controlled.

Surface mount components are used which require good soldering skills to complete this project successfully.

Using Electronic Modules:
ADS1115 4-Channel, 16-bit ADC

Cheap, ready-built modules are commonplace and they can save constructors a lot of cost and hassles, freeing up hobbyists to spend more time on more challenging and rewarding things. This month we try out a tiny ADS1115 that can add up to four high-speed 16-bit ADS channels to almost any microcontroller. It has a built-in I²C interface allowing simple connection to an Arduino Uno or Nano. We also point to some software libraries that will help you get the most out of these versatile chips.

Teach-In 2024
Learn electronics with the ESP32
Part 8: Where am I? (GNSS)

In this part, we look at applications for low cost GNSS/GPS modules that can equip an ESP32 with satellite-derived time and location functionality.

Review: Linshang LS172 Colorimeter

If you want to find a paint colour that matches an existing swatch, or verify that production batches are within spec, then this colorimeter will be ideal. It supports CMYK, Pantone® RGB and many other standards . Our review also describes an interesting history of colour matching technologies.

Also in this issue:

• Techno Talk – Max muses about how obsolete technologies still find a place in today’s world (whether we want them or not!).
• Arduino Bootcamp (Part 32) – More on BCD “and other stuff”.
• Net Work – a brief history of the digital watch, and we describe what a cheap and cheerful smart watch/ fitness tracker can offer and how they work.
• The Fox Report – holographic special effects with a new twist!
• Circuit Surgery – continuing on topics in digital signal processing – DAC outputs.
• Audio Out – Audio Switching (Part 5) – more on the concept of implementing solid-state, contactless switching.

Next month:

A wide range of projects for you to tackle, including a Secure Remote Switch; Active Rectification; a Coin Cell Emulator and a Multi-channel Digital Volume Control. On sale 3^rd October. Contents may be subject to last-minute change.