December 2017

Theremins are electronic musical instruments that traditionally use radio frequency sensitive controls to set pitch and volume. By positioning your hands carefully, tunes can be played.

Our latest Theremin project uses an Arduino-powered ultrasonic sensor to detect hand movements and (hopefully) create a meaningful tune in thin air!

Precision Voltage and Current reference with Touchscreen Control (Part 2)

This new design, based on the Micromite LCD Backpack with touchscreen, lets you generate any voltage from 0 to 37V with 0.1% or better accuracy, with the added convenience of a touch-screen interface. It can also act as a precision current source or sink from 1mA to several amps, and is largely self-calibrating.  The design doubles as a precision AC signal or DC voltage attenuator/ divider.

This instrument is a first for us: its comprehensive touchscreen eliminates switches and control knobs. Full constructional details are provided in this, the second and final part. Please note Part 1 was published in the October 2017 issue.

The Micromite Plus LCD Backpack

Combining on a single board the best features of the Explore 64 and the Micromite LCD BackPack, it can be used to supercharge your BackPack project or just as a convenient and cost-effective controller module.

Micromite Plus Advanced Programming (Part 2)

Last month some of the new features of the Micromite Plus were described, including handling files on an SD card and defining touchscreen GUI controls.  In Part Two this month, more advanced GUI control techniques are described.

You can also see a Youtube video introducing the features of the Micromite Plus.

Teach-In 2018 – Get Testing!
Part 3: AC millivoltmeters

The next instalment of our specially-written tutorial series looks at different types of waveform and how to analyse and measure them. A wideband AC range extender is offered as a simple project.

Also in this month’s issue:

• Net Work – Firefox Quantum breaks cover, and the latest interactive gadgets from Amazon.
• PIC n MIX – investigating the ins and outs of the popular 4-digit 7-segment LED display, and how to control them.
• Circuit Surgery – continuing an in-depth discussion describing the subtleties and intricacies of utilising various temperature sensors.
• Audio Out – MX50 power amplifier circuit tweaks (Part 2) Continuing the theme of eliminating ‘wet’ capacitors from the MX50 amplifier, and some testing hints.
• Techno Talk – the threat from GPS spoofing; Happy  80th birthday to RS Components.
• Max’s Cool Beans – next steps in Max’s Nixie-style countdown display timer.

Next month:

SC200 Audio Amplifier (Part 1) – first in a series offering an exceptional 200W amplifier that’s straightforward to build. DC Motor Speed Controller (Part 1) – a 12V-60V controller at up to 40 Amp, with soft start, speed regulation and low-battery cutoff. Arduino meets the ATtiny85 Microcontroller; Using low-cost modules from Asia (Part 1); Teach-In 2018 (Part 4): Component Measurements.