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awesomeshield / Awesome-Shield-PCB

MIT License
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Validate that the buzzer is compatible for the new Arduino models #27

Closed shulter closed 9 years ago

shulter commented 9 years ago

Due to the current and voltage changes at the portpin levels of the new Arduinos, a current limiting resistor might be needed in a future proof design.

cwjpalmer commented 9 years ago

As far as I can tell, buzzers have a coil resistance. To find this, I used the operating specs from the datasheet (http://www.tme.eu/en/Document/565faa25e36aa0e6e3f4693c6906e818/BZ-25SMD.pdf)

5V, 1.5mA

R = V / I = 5V / ( 1.5 / 1000 A) = 3.3K Ohm

Then using 3V3, for the new Arduinos to find current:

I = V / R = 3.3V / 3300 Ohm = 1mA 1mA < 7mA

So I think we should be okay.

One source mentioned that there's a difference between buzzers, and piezoelectric transducers. They said that piezoelectric transducers have a resistance that is ususally listed on the datasheet. The datasheet for our buzzer doesn't say it's a piezo transducer, or list a resistance. I'm going to look into this more.

shulter commented 9 years ago

No need to, that sounds solid!

cwjpalmer commented 9 years ago

great! thanks for the feedback :-)