Being a saxophonist myself, one of the tools I use the most when practicing is my metronome. A metronome is a device that gives pulses at a selectable frequency and that helps us maintain the correct tempo when playing music.
The metronome has a double indication; it produces clearly audible ticks and also swings a pendulum to give us visual feedback.
With the next project, I'd like to propose that you build a digital metronome with Arduino. If you think about it carefully, you will notice that we have almost created the core of the metronome in the previous example.
We will only add a pair of buttons to allow us to change the tempo and another LED to simulate the pendulum swing by oscillating between two LEDs.