Arduino Forum

Using Arduino => General Electronics => Topic started by: abasel on Sep 25, 2018, 12:04 pm

Title: Active buzzer plays a single tone
Post by: abasel on Sep 25, 2018, 12:04 pm
I have  an active buzzer. When I try and use it with the following example (https://www.arduino.cc/en/Tutorial/PlayMelody (https://www.arduino.cc/en/Tutorial/PlayMelody)) on an ATTiny85. I only get a single tone i.e. not pauses and no varied tones. I tried a passive buzzer but I get no sound at all. Initially I wanted to use the passive buzzer but when I could not get it to work I thought I would try it with an active buzzer (as I had a few of them lying around) and to test if the ATTiny85 was at least working. I think that I may have damaged the passive buzzer but as for the active one which is making a sound I can't work out why I am not hearing some sort of tune.
Title: Re: Active buzzer plays a single tone
Post by: MarkT on Sep 25, 2018, 12:14 pm
An active buzzer plays a single note and requires power input - its an oscillator.

A passive piezo element will respond to voltage at any frequency, but _much_ more strongly at
its mechanical resonant frequency - with only 5V drive it will be pretty quiet unless at resonance.

Connect the passive buzzer to a multimeter on AC volts and tap it - you should see some sort of reading
if its intact.
Title: Re: Active buzzer plays a single tone
Post by: abasel on Sep 25, 2018, 10:08 pm
Thanks @MarkT. It turns out that I had not check the datasheet of my passive buzzer; it has a 30V input. I have therefore ordered the following SMD Diaphram External Piezo Buzzer Transucer (https://docs-apac.rs-online.com/webdocs/14f7/0900766b814f7168.pdf (https://docs-apac.rs-online.com/webdocs/14f7/0900766b814f7168.pdf)).

Resonant Impedance is 500 ohms with 20nF capatictance. How do I need to use a resistor for this?
Title: Re: Active buzzer plays a single tone
Post by: Paul_KD7HB on Sep 26, 2018, 05:36 pm
Thanks @MarkT. It turns out that I had not check the datasheet of my passive buzzer; it has a 30V input. I have therefore ordered the following SMD Diaphram External Piezo Buzzer Transucer (https://docs-apac.rs-online.com/webdocs/14f7/0900766b814f7168.pdf (https://docs-apac.rs-online.com/webdocs/14f7/0900766b814f7168.pdf)).

Resonant Impedance is 500 ohms with 20nF capatictance. How do I need to use a resistor for this?
It IS a capacitor with a poor dielectric. No current will go through the device. Use a pulsed DC, up to 30 volts to drive it.

Paul