This highly sensitive light sensor was found in a 1970 General Electric documentation. The circuit can use the 2N2646 for the UJT and the phototransistor can be of any type.
This is one of the many anti-deboucer circuits the reader can find on this site. The base is TTL...
The idea of wearables is not new and does not necessarily need to be implemented with...
General Electric suggests this circuit in a 1980s documentation. The operational of the time is...