emonPi: Pi-powered smart meter from Welsh company
By Russell Barnes. Posted
Welsh company delivers open-source smart appliance and energy monitoring
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OpenEnergyMonitor’s Pi 3-based emonPi monitors your energy use in real time, and coordinates all your smart- and eco-tech. Co-founder Glyn Hudson told us about the company’s latest project, the emonPixel.
“For many years we’ve had a little LCD display called the emonGLCD. But it doesn’t give a whole lot of information.” Hudson informed us about his work with Energy Local (energylocal.co.uk), and a group of homes in North Wales, to develop a better energy monitoring system. These homeowners have four different tariffs during each day, depending on the behaviour of the nearby hydroelectric generator. “When the hydro is running, their energy bills are very, very low.”

emonPi: Raspberry Pi-powered smart energy monitor
Hudson wanted an intuitive display for the current tariff, so he developed the emonPixel. Based on a NeoPixel ring, the emonPi control hub monitors the energy supply in real time, and turns quarters of the ring either red or green. If the ring is fully red, don’t use the tumble dryer!
The emonPixel should be on sale soon. The OpenEnergyMonitor lists a price of £155.04 (inc VAT) £129.20 (exc VAT).
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Russell runs Raspberry Pi Press, which includes The MagPi, Hello World, HackSpace magazine, and book projects. He’s a massive sci-fi bore.
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