This circuit was found in a Popular Electronics of the 1990s. The sensor is a rotating mechanical system with a propeller-driven magnet to count pulses with a reedswitch.
This circuit is from a 1968 publication, but it can be implemented with more modern transistors such as...
With the coded activation of the relays, it is possible to control which of the 16 outputs...
This circuit appeared in the July 1969 issue of Radio Electronics magazine. The sensor is an LDR....