Piezo volume too soft

by marknano on Sat Jun 23, 2012 8:17 pm

I need the piezo speaker that came with the arduino starter kit to make a loud buzzer when called. The tone that comes out of it is very soft. I connected It to pin 9 in series with a 100ohm resistor to ground. The code that i use to call it is "tone(9, NOTE_C4, 1000)". First argument is the pin#, 2nd is the note, and the 3rd is the duration. I dont need a complicated sound. Just a basic loud buzzer enough to be heard from 20 feet. Please help.
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Re: Piezo volume too soft

by adafruit_support_mike on Sat Jun 23, 2012 9:39 pm

First, try removing the 100ohm series resistor. A piezo element is roughly like a capacitor electrically, so you don't have to worry about current flowing through it. All the resistor does is slow down the current charging the piezo element, which means it moves slower, thus producing less volume.

If that doesn't do the job, try the reference circuit in the datasheet:

http://www.tdk.co.jp/tefe02/ef532_ps.pdf (last page)

An Arduino can only deliver about 40mA of current per pin, so it's not really an audio drive circuit. A good transistor can move a lot more current (the 2N7000 mosfet is rated for 500mA of pulsed current, and the SS8050 bipolar can swing 1.5A aound).

A transistor will also let you use a separate, higher voltage power supply for the piezo element. It's rated for up to 30v, so a 12v wall wart should give you plenty of power.
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Re: Piezo volume too soft

by marknano on Sun Jun 24, 2012 4:18 am

Removig the resistor did not do anything with the volume. I will try the transistor. Thanks.
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Re: Piezo volume too soft

by adafruit on Mon Jun 25, 2012 9:50 am

Try 4000 Hz - thats the loudest tone
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Re: Piezo volume too soft

by marknano on Mon Jun 25, 2012 12:29 pm

adafruit wrote:Try 4000 Hz - thats the loudest tone


Please send me a code that will make me produce 4000hz. I am new o arduino and I do not know about sounds yet. Thanks.
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Re: Piezo volume too soft

by adafruit_support_bill on Mon Jun 25, 2012 3:11 pm

There is a functin for that in the Arduino language:
http://arduino.cc/en/Reference/Tone
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Re: Piezo volume too soft

by hydronics on Tue Nov 05, 2013 7:50 pm

I figured it out how to make a Piezo loud after way too long of tinkering! You can use 5V and you get a ton of noise.. The trick is to add an Auto-transformer to the circuit that you can get at the dollar store. I made an instructable on it here:

http://www.instructables.com/id/How-to- ... iezo-LOUD/

If anyone can identify this dollar store part on Mouser, that would be cool. cheers, tom

specs: Pin-1/2 ~154 ohms Pin 2/3 ~ 8ohms. Not sure on the inductance.
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