Go Down

Topic: Can I generate DTMF through a Piezo speaker (Read 2376 times) previous topic - next topic

beachdog

I see the Melody tutorial that show how to play a tone of specified frequency through a Piezo, but what about if I need to play dual tones simultaneously.....like DTMF tones.  Is that going to be possible with a Piezo?  As a newbie there is much I don't understand, but it seems like since the Piezo is connected to a single pin I don't see how I can generate a tone that includes two frequencies.

TchnclFl

I'm pretty sure you'd need 2 piezos running at the same time to generate a dual tone.  :-/

retrolefty

The latest version of the Tone library supports generating DTMF on board and there is an example sketch showing how:

http://code.google.com/p/arduino-tone/source/browse/trunk/examples/DTMFTest/DTMFTest.pde

However, I don't think a  Piezo is the best choice for DTMF as piezos tend to be pretty peaky in their frequency response. You would probably be better off using a very small dynamic speaker (with a series current limiting resistor), say like this on:

http://www.allelectronics.com/make-a-store/item/SK-230/20-MM-32-OHM-SPEAKER/-/1.html

Lefty

TchnclFl

Quote
The latest version of the Tone library supports generating DTMF on board and there is an example sketch showing how:


Wow!  And here I was thinking that DTMF required two piezos/speakers  ::)..

retrolefty

Quote
Wow!  And here I was thinking that DTMF required two piezos/speakers  


Oh course not, otherwise we would all have to be wearing stereo headphone for your telephone conversations.  ;)

Lefty

TchnclFl

Fair point :P.  I guess I never gave it much thought? :)

beachdog

Thanks so much for the quick and helpful answer!

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy