Those traffic loop sensors embedded at stop lights to detect the presence of a car have always provided fodder for vehicular snake oil vendors: I’ve seen products promising to eliminate red lights ...

Unlike the 2- and 3-wire transmitter representations shown in Figure 2, the 4-wire circuit has separate paths for the power current and signal current. Also, the 4-wire receiver does not share a ...

Pennsauken, N.J. — Macro Sensors has introduced a DC-operated position sensor that is spring-loaded and offers a two-wire, loop powered 4-20 mA operation commonly used with current-operated process ...

Editors' note, May 7, 2015: The co-founder of Notion, Brett Jurgens, responded to some of the setup questions I had. I've updated the piece accordingly. Between detecting leaks, watching the front ...