Date:25 July 2012
BY EMILY GERTZ
WHEN I STARTED learning DIY electronics, using Arduino was the obvious choice. This palm-sized single-board micro-controller, which can be easily swapped between projects, is designed for programming novices. Yet it has more on-board processing power than the navigation computers used by Apollo astronauts – and at just a couple of hundred rand a pop.
These qualities make Arduino the go-to component for building DIY environmental- monitoring devices, such as the electromagnetic interference (EMI) detector shown here. Because it converts invisible electric vibrations into audible sound, it’s handy for identifying sources of standby power: the energy that flows constantly through electronics, even when they’re supposedly off. Cut the power to those electronics between uses and you’ll reduce your electric bill and your carbon footprint.
When you’re ready to build something new, take this gadget apart and reuse the Arduino in your next project. Try that with a watt meter from the hardware store.
In today’s switched-on household it’s not uncommon to find a couple of dozen consumer electronics products, many with chargers or “always-on” features such as a remote control that draw a constant trickle of electricity
When the detector’s antenna picks up electromagnetic waves, it sends the voltage to the Arduino, which converts the info to a tone emitted by a speaker.
The tone will sound lower near a charging cellphone – which draws 3,7 watts of electricity on average – than near a DVR, which draws nearly 40 watts on average even when turned off.
PROJECT: ELECTROMAGNETIC INTERFERENCE DETECTOR
ROUGH COST: R300
TIME COMMITMENT: about 1 hour
SKILL LEVEL: easy
WHY MAKE IT: this is a DIY electronics skill-builder with a practical application – reducing standby power, which can make a signicant impact on residential electric bills.
INSTRUCTIONS: Build Your Own Electromagnetic Interference (EMI) Detector