i have recently taken a piezoelectric transducer out of a fire alarm and i'm hoping to use it for an arduino project...
it has three pins though... I'm pretty its voltage, ground, and frequency... i think.
i'm not too sure how to get this to produce sound, or to pick up sound... does anyone have any experience with three pin Piezoelectric transducers?
Does it have any markings that would allow you to find its datasheet? Can you post a photo?
dc42:
Does it have any markings that would allow you to find its datasheet? Can you post a photo?
I don't have a datasheet... but here is a photo of it.
The little pad is pickup section used by the driver to make it oscillate.
ajofscott:
The little pad is pickup section used by the driver to make it oscillate.
it seems you know about this type? can you be more elaborate?
how do i get this to make sound with my arduino?
how do i get this to detect sound with my arduino?
The pad attached to the large section is drive+, the brass coin part is ground. You have to drive it with a tone generator function such as is offered in the Tone Library. Or- connect drive to the collector of a 2N3904, pull the collector high via a 4.7k resistor fed by the digital pin of choice, connect the little finger pad to the base of the 2N3904 and self bias the base from the collector via 470k resistor, the emitter of course id grounded along with the piezo to the arduino's system ground. It should oscillate around 1.2KHz. The latter solution is referred to as a self driven piezo, and it has the merit of easily being driven, but can only reproduce the self oscillation freq whereas the indirect driven peizo can make sound across the audible spectrum.
If you still have the rest of the alarm, use the driver that is already on it. The input voltage most likely is 12V or 24V depending on if it's for commercial or residential use.
what if i want to use a three pin piezo to capture audio rather than to emit audio? how would i do that?
i want to use it to generate an electrical signal, rather than to send an electrical pwm signal to it.
