PIC, AVR, and Arduino are ubiquitous ... to use a momentary tactile switch to turn something on and off. Instead of going with a microcontroller he built the circuit around a 555 timer.

Here is a simple Arduino Camping Light project. In this design, only one push button switch is used to control the light output (from a bunch of white LEDs) between off, dim, medium, and full ...

[Ed] was tasked with adding push-button degaussing ... to use an SSR to switch the coil, and after making lots of transistor-based designs on paper, grabbed a nearby Arduino.

The code (Arduino sketch) allows push button increment of the counter from 0 to 9. The whole circuit can be powered from a standard ... In case of any doubt refer this table. Push Switch (S1) input ...