Wow! Yet another near-field hand-waving detector! Is there no limit to the versatility of the ubiquitous 555 integrated circuit? Not just an IC, it's a career!
Its amazing how such a small device can do so much. I have always wondered if the original designer of the 555 ever really knew what uses it would be put to.
Just checked on Google and see it has been around since 1971, and is still going strong.