  Smart meters are an enabling technology for many smart grid applications.
This paper introduces a design for a low-cost smart meter system as well as the
fundamentals of smart metering. The smart meter platform, provided as open
hardware, is designed with a connector interface compatible to the Arduino
platform, thus opening the possibilities for smart meters with flexible
hardware and computation features, starting from low-cost 8 bit micro
controllers up to powerful single board computers that can run Linux. The
metering platform features a current transformer which allows a non-intrusive
installation of the current measurement unit. The suggested design can switch
loads, offers a variable sampling frequency, and provides measurement data such
as active power, reactive and apparent power. Results indicate that measurement
accuracy and resolution of the proposed metering platform are sufficient for a
range of different applications and loads from a few watts up to five
kilowatts.
