This circuit from a Popular Electronics from the 90s uses a common optocoupler and a general-purpose transistor to control a sensitive relay that can be from 6 to 12 V.
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...