PIC, AVR, and Arduino are ubiquitous in projects these days and a lot of the time ... switch to turn something on and off. Instead of going with a microcontroller he built the circuit around a 555 ...

When transistor Q1 switches its ... by pressing the S1 button for a short or long time. Also, the load can be turned off by a short-term reset of the supply voltage when pressing the S2 button. Figure ...