Powerblade A Low-Profile, True-Power, Plug-Through Energy Meter

We present PowerBlade, the smallest and lowest power AC plug load meter that measures real, reactive and apparent power, and reports this data, along with cumulative energy consumption, over an industry -standard Bluetooth Low Energy radio. Achieving this design point requires revisiting every aspect of conventional power meters: a new method of acquiring voltage; a non-invasive, planar method of current measurement; an efficient and accurate method of computing power from the voltage and current channels; a radio interface that leverages nearby smart phones to display data and report it to the cloud; and a retro power supply reimagined with vastly lower current draw, allowing extreme miniaturization. PowerBlade occupies a mere 1 '' by 1 '' footprint, offers a 1/16 '' profile, draws 176 mW continuously, offers 1.13% error on unity power factor loads in the 2-1200 W range and slightly worse for non-linear and reactive loads, and costs $11 in modest quantities of about 1000 units. This new design point enables affordable large-scale studies of plug-load energy usage-an area of growing national importance.