Low-cost current meter.
Anthony Hathaway Berry, Dennis Scott Isenhour, Michael Carlozzi · Digital WPI · 2002
This report describes the design of a low-cost current meter sponsored by General Electric Industrial Systems. The meter is intended for residential use as a means of monitoring current consumption through a one-inch circuit breaker. This application is relevant given the recent power crisis, particularly on the West coast. The challenge is to design a non-intrusive measuring device that displays accurate information to the user. The solution developed in this project achieves non-intrusive current sensing by means of a magnetic field sensor that exploits Faraday's law. These magnetic field measurements are sampled by a PIC microcontroller and are used to calculate the true RMS current. The results show the meter to be accurate to ?1 Amp over a measure range of 0-30Amps at 60Hz.