Hi all!
Could someone tell me how to make a piezo louder? I did connect it directly to uP PIN and to ground, only 5V is avail in circuit. also I woundn`t like to use externel ICs such MAX232 to imprve voltage over piezo. I have got square wave with piezo`s resonate freq.
any ideas?
besr regards david
Drive one pin with the uP and connect the other pin to an inverted version of the same signal. I hope you have a spare inverter handy. It'll double the volts.
Graham
Homework problem?
Best regards, Spehro Pefhany
Put a small tube on it, it will "amplify it". Adjust the length of the tube for maximum sound
martin
i have got tube, i do alsa connect it with NPN key and the inductor across the piezo but it is still not lout enough any more ideas ?
Or design a tuned (eg. Helmholtz) cavity.
Best regards, Spehro Pefhany
connect the uP PIN to a transistor to switch the power (5v) through the piezo.
The uP PIN is probably only capable of driving a few Ma.
Alex.
it is capaple to rive bout 20ma, itis connected via transistir...but still not loud enough...
Drive a push-pull step-up transformer with, oh, 100mA or 200mA, then.
Best regards, Spehro Pefhany
Connect it to two inverted outputs,it doubles the voltage.
12AX7 ? ;-)
Graham
I think you mean connect it to the output and an inverted output ! ;-)
Graham
Try using a different piezo. The quality varies a fair bit from brand to brand. In general the larger ones are louder.
Place the device as it will be in the final product and hook a generator up to it and find the loudest point. This may be far from the makers published resonant frequency number, depending on the mounting.
Drive the device with a discordant sound. They always sound louder and get more attention.
Connect parallel piezo with inductor. Calculate inductance for resonanse at the maximum laoudnes of piezo. Use driver with overvoltage and other protections.
Called a "Helmholz resonator"
Dirk
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