An easy way to build a metronome, which are used by some musicians to keep in beat, and these produce a series of ticks at regular time intervals or beats per minute, a 555 timer circuit in astable mode can be used, with a varying frequency, like the one on LedLabs board, all that requires adding to the clock output (pin3) is an electrolytic capacitor around 22uf and a speaker in series to 0v, this will allow you hear the tick effect, or using an audio amp  as diagram below


Metronome from output from 555 through a capacitor or amplifier