BLINK AN LED makes clicking sound on Internet Button's Photon

What causes the clicking sound?
Can it make other sounds?

The blue user LED is blinking every second, as expected.

I’d advise you to give the documentation a try, it’s there for a reason after all.
The examples in the IDE wouldn’t hurt either.

Even the silk print at D0 (the pin used for the LED) would provide a hint :wink:
Although you’d need to take the Photon out and remove the white cover, so looking at the docs may still be easier.

Maybe worth a not for next revision, to have the silk underneath too.