[TheNext]

In earlier times circuits did not accomplish much. A resister capacitor circuit, a 555 timer, NAND NOR logic chips, analog oscillator. I got ripped off compared to Arduino today.

Arduino software is a simple loop, but effective.

[loungitude]

Hi see my post # 20.

[Cololeo]

You write functions for various things and call them from the loop. The loop is just the shell. I have written very useful programs for my photography, automating things like water drops, etc.