[FightCube] wrote in recommending a very helpful piece of circuit simulation software for those of you still constructing entries for the 555 design contest. LTSpiceIV, available from Linear ...

The 555 timer is a versatile integrated circuit (IC) that can control timing in electronic circuits. It's one of the most widely used ICs due to its reliability and flexibility.

[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 ...