Measuring the usage of domestic utilities such as water, gas or electricity ... meters have a pulsed LED output, which can be used to monitor the consumption by using an external optical sensor.

After building devices that can read his home’s electricity usage ... be sure to check out his electricity meter that we featured a few years ago.

Most inductance meters are digital, hand-held devices suitable for measuring inductance of very low value. The results of the inductance calculation can be plotted as a graph for future study.