The integrated circuit used in this detector is uncommon today. We found it in a documentation from the 70s. Detection is done by an optical camera with LEDs and a photo sensor.
This circuit is from a Popular Electronics from April 1991. The magazine no longer exists, but the...
The circuit is from an 80's publication, but the components are current, only special type diodes...
The galena XTAL is replaced by a germanium diode in this Project. Diodes such as the 1N60 or 1N34...