As we saw earlier, Wilko Lunenburg was able to make an oscillator, and even a clock, based on a tuning fork. This, then, begs the question of “what else can be made into an electronic oscillator?” and was dared by his brother to make one out of a wineglass. Lunenburg correctly assumed this task would be more difficult than using a tuning fork, but after quite a bit of experimentation, he was able to rise to the challenge.
The first task was actually making the glass vibrate, and unlike the tuning fork, he couldn’t use magnetism to strike it. While a mechanical wet finger could possibly be used to rub the top and make it sing, he instead decided on a piezo element to make the glass vibrate using sound waves.
From here, a detection method was needed, which turned out to be the most difficult part of the project. The initial idea was to set up a sort of laser microphone that a spy might use to listen to vibrations on glass, but given this project’s short range that wouldn’t work properly. Using a traditional microphone here was also ruled out, as the sound from the speaker would overpower the sound from the glass. Another idea was to use the glass to bend light, but after that was unsuccessful, he finally skimmed a laser beam across the glass in such a way that allows the wineglass to block most of the light and modulate with its vibrations.
This skimming technique is a very sensitive setup, but after some filtering, he was able to feed the proper amplified signal to a speaker, causing it to oscillate. While it won’t replace traditional crystal oscillators any time soon — or even tuning forks — it’s an interesting experiment, as seen in the video above.
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Author: Jeremy S. Cook