This “people detector” with pyroelectric sensor was found in the April 1991 issue of Radio Electronics magazine. The circuit is based on an LM324 and a sensor from that time.
With the coded activation of the relays, it is possible to control which of the 16 outputs...
The integrated circuit used in this application is not very common. Transistors and resistors...
This simple circuit makes use of neon lamps to indicate the voltage of a power grid. The lamps are...