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
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
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
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
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
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
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.
-- -- kensmith@rahul.net forging knowledge
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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