June 2019

Wide-range Arduino-based LC Meter

This easy-to-build piece of test gear uses a custom Arduino shield, a backlit 20 x 4 alphanumeric LCD and measures capacitance from less than 1pF to over 1F and inductance from < 100nH to several henries.

It features very low drift thanks to a constant self-calibration procedure, accuracy of ±1% and a sample rate of once every two seconds. A valuable addition to the constructor’s test equipment array.

USB Flexitimer

This very useful timing module drives a DPDT relay and will find many applications in home, DIY, car, security, workshop, horticulture, lighting and other areas.

Configurable in a multitude of modes, it’s perfect when you need a versatile timing function, and it can operate in astable or monostable modes with on-off periods from milliseconds to 50 days. It can be adjusted using its on-board trimpots (optional) or fully configured using a laptop PC via its USB port.  Multiple triggering options available.  Easy through-hole PCB construction on a self-contained PCB and full, easy-to-use programming instructions are included. The best Flexitimer yet, and sure to prove a ‘stock’ solution for many timing needs.

Using Cheap Asian Electronic Modules (Part 17)
4GHz Digital Attenuator Module

We investigate a highly linear digital attenuator module that’s available ‘off the shelf’ as an import.

Based on the PE4302  i.c., this RF attenuator provides any desired level of attenuation from 0dB to -31.5dB. Our feature includes a full explanation of operation and use.

MIDI Ultimate Synthesiser (Part 5)

This month’s instalment of this amazing synthesiser design offers an in-depth overview of the MIDI interface itself, a look at the author’s home studio MIDI setup and details of the MIDI hardware for the Ultimate Synthesiser.

Teach-In 2019
Powering Electronics (Part 7)

The penultimate part of this tutorial series devoted to all aspects of power supply design for the electronics hobbyist focuses on the principle of heatsink selection and the correct way to mount power semiconductors on them.

PIC n’ MIX

More on the small, cheap but powerful PIC10F microcontroller series, demonstrating a ‘smart’ power switch.

Audio Out – the PE Theremin (Part 1)

Jake Rothman, our resident analogue audio and Theremin expert, embarks on his latest project, the new PE Theremin. We start with an in-depth primer on Theremin basics and introduce some of the sound generator circuitry to readers. A real treat for Theremin fans everywhere and not to be missed!

Also in this issue:

• Techno Talk – some of the hidden perils of LED lights and shortcomings in the UK’s CLID technology
• Net Work – ‘whole home’ mesh networking explained
• Circuit Surgery – Introduction to Circuit Simulation with LTSpice (Part 5)
• Max’s Cool Beans – options for ‘micing’ the Arduino
• Make it with Micromite – continuing the traffic lights demo, subroutines, interrupts and IR control.

Next month

Full-wave 10A Universal Motor Speed Controller; Recurring Event Reminder; Temperature Switch Mk. 2; Low-cost Modules (500MHz couinter, wideband amplifier). Teach-In Part 9 – battery types; MIDI Ultimate Synthesiser (Part 6).