April 2017 Issue

A summary of this month's contents.

Arduino Multifunction 24-bit Measuring Shield (Part 1)


Measure voltages, decibels and power levels with this low-cost Arduino-based PC measuring system. It has four accurate DC ranges and an AF level and power meter, plus an optional RF level and power meter that can operate up to 500MHz.  It links to a PC (Windows 7+) via USB, and captured data can be logged in .csv format for later analysis.


Arduino Uno (or similar) based, 24-bit resolution.  Circuit principles and hardware construction are described this month with usage guide notes offered in Part 2 next month.



Battery Pack Cell Balancer

Many traditional battery chargers treat a ‘battery’ as a single unit with no regard for the state of the individual cells it contains. Over time, this brute-force approach to charging can result in a cell failure that renders the entire battery pack useless.  This clever project is designed to ensure the charge between cells is balanced properly and avoid cells from being ‘abused’.


It periodically checks the voltage across all cells contained in a battery pack and shunts the charging current(s) to ensure uniform charging. It balances Li-ion, LiPo or LiFEPObattery packs up to 33.6V (8 x 4.2V max) and can extend the lives of NiCd and NiMH packs too.


Plugs directly into typical battery balance connectors. Charging current 10A or more, LED status indicators. PIC microcontroller based, with free .hex file available from our Library.


Surface mount components used throughout. Good soldering skills are needed to complete this project successfully.


Microwave Leakage Detector

This mini-sized module measures leakage emanating from microwave ovens and displays the reading on a simple LED bargraph.  By passing the detector around the edges of the oven door, any variations in field strength can be seen and investigated.


Surface mount design needs good soldering skills


Meet the Mighty Micromite (Part 3)

Programming the Micromite in MMBasic


Micromite is a BASIC-programmable microcontroller capable of handling many interfacing, control and logging applications, limited only by your imagination. In Part 3 we show how to program a Micromite using MMBasic, a language very similar to Microsoft BASIC popular some years ago.


Handy Micromite Links:


UK Micromite Shop http://micromite.org/








Our PIC-microcontroller expert continues with the development of his LED Binary Clock as a worked example of modern microcontroller product design and development.


Please Take Note


On the stripboard layout Fig 4 (March 2017) , for correct operation a cut is needed in the track at location M11.


Also in this issue


  • Techno Talk – Zero Ohm resistors (!) and how lithium could soon be mined in Britain
  • Net Work – The Fitbit fashion and Amazon Fire TV Stick
  • Ingenuity Unlimited – Readers’ own circuit ideas
  • Circuit Surgery – variable voltage PWM techniques
  • Audio Out – two book reviews for the audio enthusiast
  • Electronic Building Blocks – a new control system for a spot welder
  • Max’s Cool Beans – further thoughts about his new Bodacious Brain project


Next month

The Micromite LCD BackPack; Arduino Multifunction Measuring Shield (Part 2); Precision 230V/ 115V 50/60Hz Turntable Driver. Contents subject to change.


EPE is packed with practical electronics projects and theory for the hobbyist. You can order a printed copy of EPE for delivery to your door (worldwide), or try the PDF Version (needs Adobe Reader for Windows), or the Pocketmags for your mobile device. Subscribe now!



Source code file 0417.zip


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The April 2007 issue had a Student's 20W Mono Amplifier module, a Star High Power LED power supply, PIC Polyphonium (Part 2) and SMS Controller (Part 2).


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