October 2015

Digital Effects Processor for Guitars and Musical Instruments

This deceptively simple unit offers ten different musical instrument effects including echo, reverb, tremolo, fuzz, compression, flanging and phasing. Each effect is adjustable and can be defeated with an optional foot pedal switch.

Designed for electric guitars but will work with other instruments and vocals too. Optional headphone output and mic pre-amp.  PIC 32MX microcontroller powered, free source code available from our Library.

 Surface mount design needs good soldering skills

Opto-Theremin (Part 2)

A 21^st Century update on a historic discovery in electronic music making, our latest Opto-Theremin uses light sensors for a manual volume control combined with the original principle of using a vertical radio antenna for pitch control.

By manipulating one’s hands around the sensors, it is possible to produce a very exciting, intriguing and sometimes weird electronic music and sounds. It has a Line Out as well as an integral speaker.

In Part Two this month, assembly details are described.

 Surface mount design needs good soldering skills

Courtesy LED Lights Delay for Cars

Designed with older cars in mind, this unit is specially designed to suit LED lamps but also works with conventional filament bulbs. It keeps the car’s interior light illuminated for a preset time after you shut the car doors, and they will be extinguished if the exterior lights or ignition switch are activated during the time-out period. PIC 12F micro powered, free code available from our Library.

PIC n MIX

After a decade of writing popular articles for our readers we bid a temporary farewell to Mike Hibbett who brought the power of the PIC microcontroller to many. We welcome our new PIC expert, Mike O’Keefe who takes over the reins this month with the conclusion of the LPLC Oscilloscope.

Teach-In 2015 (Part 9)

Our penultimate tutorial in the series devoted to discrete linear circuit design looks at classic designs for loudspeakers as loads, amplifier stability, amplifier thermal protection and more. TINA software is used to analyse circuitry. Then the design and construction of a high performance 10W audio power amplifier are described.

Also in this issue:

• Net Work – Amazon’s acquisition of ‘Top Gear’, Flash vulnerabilities and trends in web site designs
• Interface – Raspberry Pi and Pulse Width Modulation principles
• Circuit Surgery – current mirrors and transistor matching explained, and SPICE modelling
• Audio Out – our enthusiastic audiophile describes some test routines for RIAA equalisation.
• Max’s Cool Beans  – more on using Tri-Colour LEDs
• Electronic Building Blocks – adapting cheap and cheerful modules that cost next to nothing online. This month, a 9W stereo amplifier.
• Techno Talk – the latest trends in solar power.

Next month:

The Currawong 2x10W Stereo Valve Amplifier (Part 1); Programmable Mains Timer with Remote Switching; 48V Dual Phantom Power Supply for DI boxes & Condenser microphones;Teach-In 2015 Part 10: practical measurement, adjustment and faultfinding in power amplifiers.