The sensor is S1 in this alarm that we found in a Radio Electronics magazine from May 1971. Several sensors can be used in series. The SCR supports equivalents from the 106 series.
This 9-pixel circuit has been implemented with 9 LDRs and can be coupled to a processing system for...
This circuit was obtained in a 1979 magazine, but it can be easily assembled today, as the...
The presented circuit makes use of a common operational amplifier that must be powered by a...