Piezo

Other Hardware General Electronics
1

Hello,

I am am fairly new to arduino, and working on a project where i use a LED matrix (5x6), some buttons and a piezo.

This is my schematic: Screenshot by Lightshot

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As u can see, i put my piezo piece inside the LED matrix, due to the lack of more digital/analog pins. The way i have it set up right now, works. but.. whenever a led from the top row is set to high.. the piezo (which is on the same 0V as the top row leds), will make a tick sound.

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i tried placing a diode behind the piezo:

When i do so.. the ticking stops whenever a led on the top row gets set to high, but the piezo itself wont work anymore.

Any ideas as to what i should do?

Thanks

2

If you're out of I/O pins, the only thing I can think of is to get rid of the LED matrix and use [u]shift registers[/u].

3

DVDdoug:
If you're out of I/O pins, the only thing I can think of is to get rid of the LED matrix and use [u]shift registers[/u].

I cant get rid of the matrix.. :confused:

4

Or you could have CharliePlexed the LEDS and used only 6 pins to drive them...

5

Hi,
Your Piezo is just that, a Piezo element and it is responding to the DC you are applying to it.

I think what you were expecting was a BEEP.

You need to get a BEEPER.
OR make the output of the Arduino, oscillate at the tone you would like to hear.

Tom.. :slight_smile:
PS. Write some code to just drive the Piezo.
Try Tone library.

6

DVDdoug:
If you're out of I/O pins, the only thing I can think of is to get rid of the LED matrix and use [u]shift registers[/u].

I think what was meant was.
Keep the matrix, BUT drive it with a shift register.
OR
MAX7219 IC.
Google Arduino 8x8 MAX7219
It will give you examples, modifying to 5 x 6 should not be hard.
Tom... :slight_smile: