Piezo question

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Hi Freaks,
I am planning to drive a piezo directly from my Attiny24 digital o/p pin. All I am looking for is a simple low current(but loud) piezo speaker. I am thinking of using PWM to control the speaker. Also my Tiny runs on 3.3V so I would like to save power.
Any ideas for a good, loud but low resistance speaker?
Thanks.

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Piezo != (magnetic) speaker.

For your intended application, piezoelectric buzzers are the best option due the low power consumption, but they are usually limited to play 'high' tones (>1500Hz).

If you plan to use AC type piezos (the simpliest and cheapest ones), then you can play music, but then you have to play with timers. After all, music is a question of time and frequency. You can try Murata, OBO, Hitpoin (IIRC), Kingstate or others at your preferred supplier.

Have fun.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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Thanks, Guillem.

I think I will stick to Piezoelectric buzzers. All I need is a simple beeping buzzer. I don't need any music or anything. Do you know any popular, commonly used piezo buzzers?

Also a buzzer needs only supply and GND right? So all I will have to do is connect it to a port and send high and then low right?

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Actually, I will need a piezo which can beep ON and OFF at a frequency and also be able to generate a continuous beep;the time for which I should be able to program from the Tiny.

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the piezo buzzers simply emit a constant tone. If you want beeping you modulate the input at your beep frequency (aka turn it on and off).

Writing code is like having sex.... make one little mistake, and you're supporting it for life.

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Looks like this may be a good one.

[url]
www.murata.com/catalog/p15e6.pdf
[/url]

I may have to go for the PKB24SPC-3601-B0 part.

Any ideas what is the difference between a self drive and built in circuit?
I think self drive should be ok and I can use the AVR to turn it ON/OFF.

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That is a very useful link. Thanks.

This one looks like a good one to use.

[url]
http://www.allelectronics.com/ma...
[/url]

It says emits medium-high tone when energized which would mean it has a self drive circuit in it?

I wish there was a spec. showing the SPL vs. supply voltage.
I want to use it at 3.3V.

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Quote:

Any ideas what is the difference between a self drive and built in circuit?

Built-in circuit has built-in oscillator, fixed tone.
Self-drive means you have to drive it (like a speaker) with a tone, square wave is OK.