July 2018

Touchscreen Energy Meter for Appliances (Part 1)

This very modern and versatile design measures the mains voltage and an electrical appliance’s load current to calculate the power being consumed. It takes into account the appliance’s power factor and determines the total kilowatt-hours used, and also displays the true running costs using the electricity tariffs configured in the meter.

The sophisticated design is based on a ready-made Micromite Mk2 LCD Backpack which hosts a 2.8” 320 x 240 colour touchscreen LCD to display power consumption data in both digital and graph form, including voltage, current, frequency, real power, power factor, VA, kWh and energy costs.  The Energy Meter can measure up to 20 amps (100A surge) and displays a multitude of parameters which can be computed from your electricity tariff.  Data can also be downloaded from the logger onto a PC via USB.

In Part One this month, the circuit operation is outlined along with a tutorial using sinewave graphs to explain the principles of voltage, amps and energy. Constructional and usage details are provided in Part Two next month.

 Surface mount design needs good soldering skills

Automotive Sensor Modifier

A deceptively powerful project that enables vehicle sensor outputs to be modified, eg to compensate for modifications or tuning to “trick” the ECU into operating correctly, or to tailor the response of an engine to meet individual requirements. Possible modifications include oxygen sensor level, air/fuel mixture, turbo boost cut, throttle position sensor response, fuel injector changes and air flow meter changes.

It’s straightforward to build on a single pcb which also carries the push switch controls and a two-line mono LCD. How to use the popular Torque app for Android is also suggested.  PIC microcontroller based, with free .hex file available for download (see top right of this web page).

 This is an advanced design for very skilled electronics and automotive enthusiasts. Using the Automotive Sensor Modifier could result in engine damage if the programming adjustments are not done carefully and methodically. Your vehicle insurance cover may also be affected by this engine modification.

High Performance 10-Octave Stereo Graphic Equaliser (Part 2)

In last month’s issue we described the circuit and performance of our new 10-octave Stereo Graphic Equaliser. This concluding part covers the assembly of the main board and acrylic cover, and initial testing and powering up.

Cheap Asian Electronics Modules (Part 7)

Trying out an SPI (Serial Peripheral Interface) 8×8 LED Matrix Module and discovering some surprises! Use them with a Micromite, Arduino and more besides to produce a versatile opto display with little hassle.

Lascar PanelPilot Voltmeter Review

A review of a new type of programmable panel meter from Britain’s Lascar. This very versatile alphanumerical-graphical display uses ‘e-paper’ technology and is software programmable. What can it do for you? EPE takes a quick look.

Audio Out

Considerations and actual examples of the benefits and satisfaction of repairing older circuitry instead of throwing it away. Our analogue audiophile offers plenty of practical hints and tips to give older electronic circuitry a new lease of life.

Also in this month’s issue:

• Techno Talk – the quest for consumer batteries using liquid electrolytes
• PIC n MIX – the final part of our mini-series offering a practical DSP
• Electronics Building Blocks – How to add a digital tachometer to a home workshop machine tool such as a lathe or milling machine. All for next to nothing!
• Net Work – Facebook’s woes; Data Protection’s big guns
• Circuit Surgery – chopper and auto-zero amplifiers (Part 2)

Next month

Energy Meter for Appliances (Part 2); Universal Temperature Alarm; Low-Cost Electronic Modules (Part 8): Li-Ion-Li-Po charger modules; Power Supply for Battery-operated Valve (Vacuum Tube) radios.