Piezo Speaker

[helm-2-108]

Hello

I recently purchased the kit for a project.
All arrived extremely quickly.
Kit was assembled, and is working great…

However, I have a question about the supplied voltage and rating of the speaker.
For my particular use the speaker does not provide enough volume.

I purchased and attached a 3-20VDC/(95dB @3vdc)(105dB @20vdc) piezo speaker, and the volume has not changed.

Can anyone help me in my endeavor?

Once the volume issue is straightened out, i will start tackling the software, and would more than willing to post the changes i have made so that others can use them.

Thanks ahead of time

[Michael]

Hi helm-2-108,

I think you’ll get much better volume from a small 8-ohm speaker (found in many products, or very cheap). I believe you should use a resistor in series with the speaker. See this page for some more info:
http://arduino.cc/en/Tutorial/tone

[helm-2-108]

@Michael wrote:

Hi helm-2-108,

I think you’ll get much better volume from a small 8-ohm speaker (found in many products, or very cheap). I believe you should use a resistor in series with the speaker. See this page for some more info:
http://arduino.cc/en/Tutorial/tone

Michael, thanks for responding so quickly.

Could you tell what the voltage is to speaker you provided with your kit?

I understand the concept of adding the resistor in series with the input line to the speaker, but i am unsure of the voltage being supplied to the speaker for that particular output. Given the voltage i can find a speaker/buzzer with the suitable power to complete the task w/ the line voltage. Out of curiosity you would not happen to know the specs for the speaker/buzzer that was included with the kit?

On a further note just wanted to tell you great job on the kit. Was easy to assemble and worked correctly the first time power was applied. If i can i get the issue with the volume/speaker sorted, i shall be ordering a few more of these kits, a they are right in the wheel house for the project. thanks again.

[Michael]

The voltage is 5V. The piezo buzzer is driven with a 5V PWM signal (a square wave making it oscillate). A speaker would sound similar but more of a clear tone and louder.

[helm-2-108]

Michael

Thanks for the input so far…
I purchased a 8 ohm .2w speaker and hooked up in series with a 100ohm resistor… the volume change was insignificant.
On a guess a placed a 50ohm resistor in series with speaker and the volume did get louder, but not by a factor of 2.

I am open to suggestions…

Thanks ahead of time

[Michael]

Oh, I thought it would be a bit louder. I don’t have a simple solution for you, as you need to amplify the signal significantly to get a louder sound. A microcontroller output pin isn’t designed to deliver more than 30-40mA of current and isn’t suitable for generating that much sound energy. You need an amplifier of some kind.

[helm-2-108]

@Michael wrote:

Oh, I thought it would be a bit louder. I don’t have a simple solution for you, as you need to amplify the signal significantly to get a louder sound. A microcontroller output pin isn’t designed to deliver more than 30-40mA of current and isn’t suitable for generating that much sound energy. You need an amplifier of some kind.

after talking with some people who are more knowledgeable about waveforms and acoustics i am looking into using a capacitor in the speaker circuit to help dampen the dc throughput to the speaker, evidently and do not quote me on this, the dc signal is “swamping” the speaker, and by blocking some of the dc signal “we” al;ow the ac signal to be sent to the speaker, this would produce more volume since the speaker is not being “swamped”.

Understand that I am paraphrasing a lot of this because a good chunk of what i was told is bit over my head. However I have enlisted help in determining what size capacitor to use, also have to figure out how to tune the circuit, not sure what this all means, this is a “crash course” for me.

But I will share my/our findings so that others may gain some help.

First try is going to consist of a 47ohm resistor in series w/ a 10uF cap connected to the speaker(8ohm .2w)

Update****

Success!!!! at 120ft the beeping is clear and distinct!!!!

Now to tackle the ending sequence of the detonation, to make it more clear and distinct, which if i am correct is going to be handled via the programming.

Just wanted to say thanks for bouncing ideas around with me!!!

[Rick0413]

Can you post pictures of your final solution? I am very new to the electronics and would also like to increase the sound capacity of the clock. Thanks.

[taggart]

helm could you possibly elaborate on the parts. I have tried the same setup but was unsuccessful in increasing the volume. I too dont know a whole lot about this and there are SOOO many options http://www.jameco.com/1/3/10uf-capacitor. And Im not 100% about the resistor either, as far as I can tell it is a 1/4 Watt (Purple – Black – Gold). Does this resemble what you used, what are the exact specs on the capacitor?

[Author]

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