Project for ultrasonic piezo buzzer at 40Khz along with power question

Projects General Guidance
1

Brand new to this forum and arduino in general with not a lot of electronic background but, trying to do the following project.

Purchased and assembled the arduino nano along with a passive buzzer 10mm i found on amazon.
I've uploaded code for it and it does power up via usb connection, makes a sound and i can change the frequency range. My question is i'm pretty sure humans aren't supposed to hear in the 40khz range and i can hear this annoying noise from it which gives me a headache so, i'm wondering how do you know if you have the right buzzer? I only want to cover like a 5-10ft radius of ultrasonic sound. second part is i'd like to put this on an ethernet cable between a switch and another device and just draw enough power to power this via a few watts of poe, not sure how to accomplish this.

attached a pic of my project and thank you for any input.

adruino.JPG
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2

You're probably hearing a harmonic, assuming your code really does generate a 40kHz signal.

3

thanks for the reply, would it be helpful if i post the code

4

Are you sure is't a passive buzzer.
Passive buzzers usually don't have a + sign on top. Your one does.
Try the buzzer on the 5volt pin.
Leo..

5

Thx for the reply wawa.
well i believe so :slight_smile: also not sure how to plug the buzzer into the 5v as next to it is a jumper.
think i should have bought a buzzer with wires vs. pins for more flexibility.
buzzer i got was this one

I'm basically trying to replicate this project i found see if i can get it to work the same.

But then put it on a power over ethernet pass through connection to draw enough power from the poe to power it or maybe battery powered for 24/7 operation.

6

Or connect the buzzer to a 9volt battery.
If it makes a tone, then it's an active buzzer.

Not sure what POE has to do with anything.
The Nano only has a USB socket.
Leo..

7

Looked up the Amazon site and see this: 2 Terminals,complete drive circuit incorporated for direct operation from AC power source.

Even though the text says AC, the + on the case means it is is an active piezo with a single frequency output.

If the device causes you a physical problem and you are not hearing the tone clearly, you have a hearing problem that should be remedied. I had the same problem with the piezo in the Arduino starter kit and after getting hearing aids, the device clearly is working!

Paul