You know how it is. You’ve got that new project running, and while it doesn’t consume much power, it also doesn’t give much indication of whether it’s functioning or just sitting there with a dead ...

A LED flashing briefly once every 5 seconds to imitate the indicator of a real alarm is the function of this dummy alarm project with the use of a 7555 timer IC. To prolong battery life, the circuit ...

It is a pretty common first project to use an Arduino (or similar) to blink an LED. Which, of course, brings taunts of: you could have used a 555! You can, of course, also use any sort of oscillator, ...