To accomplish this task, he looked over the internal block schematics of a 555 timer and constructed a pair of high-power 555 timers himself, using discrete components to mimic those usually found ...

It’s a constant of writing for Hackaday, that whenever a project appears using a 555 timer, someone will say “You could have used a microcontroller to do that!”.

An astable 555 multivibrator circuit, where the timing characteristics are determined by the interplay of an inductor, resistor, and diode.