“A metronome is any device that produces a regulated audible and/or visual pulse, usually used to establish a steady beat, or tempo, measured in beats-per-minute (BPM) for the performance of musical compositions. It is an invaluable practice tool for musicians that goes back hundreds of years.”(wikipedia about metronome)
Basically the project consists of 3 resistors, 2 capacitors, 2 led’s, a speaker and the 555 IC so its not much that can go wrong. I recommend this project to beginners, you can either fabricate a PCB for it or just assemble it on a breadboard.
555 Simple Metronome: [Link]