John R. Wiegand

John Richard Wiegand (February 23, 1912 – December 1986)  discovered the Wiegand effect, a physical phenomenon in which a special wire, called a "Wiegand wire", produces small magnetic fields. The accompanying Wiegand reader detects the magnetic pulses produced by the two-domain wire embedded within, typically, plastic cards. There is also a Wiegand interface commonly used to transmit the data collected by a Wiegand sensor in a card reader. The Wiegand effect was first thought to be a commercially viable solution to better ignition systems for internal combustion engines. Echlin Corporation, an automotive parts manufacturer owned Sensor Engineering of Hamden, Connecticut in the 1970s. That application was displaced by the electronic ignition system.