October 2018

6GHz+ Touchscreen Frequency & Period Counter (Part 1)

Based on the Micromite Plus Explore 100 module, this sophisticated new touchscreen design supercedes the 2.5GHz 12-digit Frequency Counter we described in the January and February 2014 issues.

This new 6GHz design has unparalleled performance, offering much higher maximum and lower frequency measurements (10mHz – 50MHz low freq. input, 6MHz-6GHz or more, high freq. input). Plus of course a large 800 x 600 24-bit colour touchscreen means a radical upgrade of its display capabilities combined with the convenience of touch-screen operation.

In Part One this month, circuit principles are described with construction and calibration to follow in Part Two next month.

  Surface mount design needs good soldering skills

3-Way Fully Adjustable Stereo Active Crossover for Loudspeakers

Last month we described the circuitry of our new Active Crossover. In Part Two this month, we continue with the constructional details, building the PCB and final assembly of the project into its acrylic case.  All assembly details are described clearly in full colour enabling this design to be assembled with confidence.

 Surface mount design needs good soldering skills

230V Cyclic Mains Timer

This useful device can limit the damage or risk arising when a mains-powered device operates for a longer period than is normal, possibly indicating that a fault condition has occurred. Examples include unattended pumps or compressors, or many other motorised electrical equipment.

The project monitors when mains power is being consumed and if it runs for longer than usual, its internal relay will disconnect the power. It has a further application as a simple period timer that times out after a preset delay, to prevent an apparatus from being left powered up accidentally, eg soldering iron.

It has switching contacts rated at 30A and a run-time of 1-100 minutes as a cyclic pump timer, or 2.5-250 minutes as a simple period timer. PIC 12F675 controlled with source code available from our web site (see link, top right).

WARNING MAINS VOLTAGE

High Voltages  are present throughout.  This design is suitable for skilled and experienced constructors only.

Using Cheap Asian Electronic Modules – Part 10
Two Low-Cost GPS Receiver Modules

Combining low cost with impressive performance, we investigate two GPS modules – the V.KEL ‘GMouse’ VK2828U7G5LF AND THE U-BLOX Neo-7M and show you how to use them in all kinds of projects.

PIC n’ MIX

Part 2 of our PIC columnist’s PICMeter delves into some SPI considerations and continues with source code development. This month’s files are available for free download  (see link, top right).

Circuit Surgery
Introduction to Circuit Simulation with LTSpice (Part 1)

The start of an excellent new tutorial series introducing LTSpice (and SPICE simulation in general), our ‘Surgeon’ Ian Bell points the way to downloading, installing and using LTSpice to help you simulate and develop electronic circuits. If you’ve never used a simulator before then don’t miss this top quality primer from EPE! This month’s files are available for free download  (see link, top right).

Audio Out – Analogue Synthesis (Part 3).

Our analogue audiophile continues to design, develop and construct the building blocks of an analogue synthesiser: the keyboard, controller and VCO are built on PCBs with free PCB files available for download this month  (see link, top right).

Also in this issue:

• Techno Talk – Are light bulbs ruining your radio? The hidden perils of LED bulbs that manufacturers don’t want you to know about.
• Lucy’s Lab – how our new columnist got into engineering in the first place
• Electronic Building Blocks – Mini Hydro Power Station – exploring a cheap and cheerful mini turbine generator that fits into a domestic hosepipe or plumbing, to generate some small but useful electrical power when water flows through.
• Net Work – the Internet column – Is interest in the Internet peaking? Recent reports on fake news and the ‘digital dependency’ culture highlight current trends and thinking.

Next month

6GHz+ Touchscreen Frequency & Period Counter (Part 2); Super-7 AM Radio Receiver (Part 1); High-performance Dipole Loudspeaker; SDR (software defined radio) radio review.