This simple three-LED sensor uses an NTC at the input. The circuit is based on an uncommon integrated component today. We found it in documentation from the 80s.
This article is old, from 1994. But, for those who have an old PC and want to use a joystick from...
The passage of an object in front of the LDR, producing a shadow or even turning off the ambient...
The transistor used in this circuit is uncommon today. AC124 or equivalent such as AC188K and...