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How can I get a loud alarm? Answered

Ok so I need an alarm for my project, a very loud alarm. . .

And I can't seem to get these dumb buzzer to output a decent sound. I have a lipo checker that uses these type of buzzers
 and they are ear shattering. I tried putting the regular buzzers and the were no where near as loud.


Also if I want to use the tone function on the arduino, how do i make the buzzer louder?

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user
Downunder35m (author)2015-04-19

I guess you misunderstood the function of a buzzer.

A buzzer requires a DV input and produces a sound with a fixed frequncy.

A pieco speaker requires an audio or PWM input signal and changes the tone with the frequency.

You can try what you want with a buzzer but it won't change much on the output.

Get a normal piezo speaker or siren and feed it with a proper PWM signal to adjust frequency and loadness - the later depends on the volume level (amplitude).

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HavocRC (author)Downunder35m2015-04-20

Hey thanks man. After posting this I read up on active and passive buzzers and figured that out. I'm still having trouble making a loud alarm with the piezo speaker.

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Downunder35m (author)HavocRC2015-04-22

To make it really load you need a suitable housing for it - like the piezo sirens for home alarms.
They focus the sound and due to the construction also increase the sound pressure dramatically.
Remove the plastic housing from a piezo siren and you get a load beeper ;)
Depending on your model you can use the feedback contact to optimize the frequency, otherwise stick to the rated power levels and play with the frequencies.

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caitlinsdad (author)2015-04-19

https://www.instructables.com/id/How-to-make-an-Ard...

I think the pwm coming out of the arduino pin doesn't have enough oomph to drive the piezo loud enough.

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HavocRC (author)caitlinsdad2015-04-19

Exactly. That's why I asked "how do I make the buzzer louder?" I know I can output a sine wave/whatever wave from the arduino, but what do I need to make amp the signal?

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caitlinsdad (author)HavocRC2015-04-19

Read through the ible and image notes. The amp is that mystery chip/component in one of those small alarms.

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user
HavocRC (author)caitlinsdad2015-04-19

It seems like all that thing does it produce a wave. . .

If the transformer isn't the amp then. . .

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caitlinsdad (author)HavocRC2015-04-19

think of that autotransformer thing as a control valve or power transistor for the battery's full current. It opens and closes in sync with the pwm tone signal from the arduino. I guess really not an amp in that sense.

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