Mode Zero

Does anyone have a part number for a\the piezo buzzer Phil G calls out in several of his projects?

Digikey or Mouser would work.

Thanks

Dave Rigotti

It not a piezo Dave, its a magnetic buzzer. Piezo sounders need to be driven from a squarewave audio signal, whereas the magnetic buzzers work from pure DC. Piezos are more akin to a speaker than a buzzer.
They look similar but DC ones have a long and a short leg and have inherent magnetism. I get them from ebay, just search 9mm x 12mm DC buzzer and avoid any that say 'piezo'. The actual device is a 1205X or HCM1205X. They're quite greedy at around 20-30mA, and generate a lot of hash, hence the 2N3904 transistor driver. The 328P can just about drive one directly but its on the limit and the pin is being pulled out of saturation, so I always buffer them. PIC pins cant manage 30mA anyway.

There are some piezo's with an inbuilt oscillator to make them run from DC - but these are rarely seen and are relatively expensive - I tried to buy some, but it turned out they weren't driven piezo buzzerss at all, just ordinary DC magnetic buzzers. I sent this to the seller:



Cheers
Phil

Thanks Phil for the information.
This looks promising....
https://www.mouser.com/ProductDetail/Ko ... fakA%3d%3d

Dave Rigotti

If you want to buy from a bona fide distributor then Rapid Electronics does similar 5V buzzers for less than mouser:

https://www.rapidonline.com/SoniCrest-H ... hwQAvD_BwE

And if you are using a lipo battery to power the Arduino and are going to use a transistor to switch the sounder, then I always use a 12V sounder and power it off the 7.2V, which saves the odd 30mA from the 5V regulator. That may not sound important, but if you are using the ADC to measure say a potentiometer voltage, you do get a change of reading every time the sounder switches on or off if powered from the Arduino 5V.

https://www.rapidonline.com/SoniCrest-H ... boQAvD_BwE

But if you aren't UK based the above links probably aren't of much use...

Mike

I ordered these from eBay....
https://www.ebay.com/itm/182700170241
Thanks for all the input!

Dave Rigotti