O.C.P.: Oscilador Calçada Portuguesa (Portuguese pavement oscillator)
Portuguese pavement (Calçada Portuguesa) is a traditional style of pavement made with stones and its used mostly for pedestrian areas.
Today walking in the sidewalk I started made associations, rock on the sidewalk, rock stable oscillator and then I was "struck" by light, eg: had another "stupid idea".
What if I can use the mini quartz crystal formations on the stone for an oscillator, heck, someone made it's own transistors, diodes and valves, why can't I build a crystal....today was the day!
I went to a nearby street were they were placing "calçada Portuguesa" and borough one stone....
I have a technical notion on how to break a stone: just it her with the hammer!
Got a small piece and then made a support and hoke it up to the test oscillator...
...here's the result:
....Initialy it didn't started to oscillate because the crystal part on the rock was not making contact with the copper foil. I then grinder a little bit the piece of rock and incredible it started to oscillate, this one was near the UHF band, bigger pieces give lower frequencies.
After some more tests, discovered that I got around 10Khz higer on frequency by each time the stone was reduced. The frequency is as stable as a normal crystal but also depends on the force applied. So a screw can be placed to fix the rock and make a simple vfo.... cool!
Have fun today!