Used in a variety of timer, pulse generation, and oscillator applications, the 555 was designed in 1971 by Hans Camenzind. A favorite for many engineers, the 555 is still in widespread use due to its ...

[R-B] designed a 555 timer circuit to scan a keypad. Keypads are common interfaces for small projects and require row and column scanning by a microcontroller. [R-B’s] setup allows you to reduce the ...