Piezo buzzers...

[crazyfazy_7]

Hi. Does anyone know if there is a site out there, or a way to listen to the different sounds of piezo buzzers so you can hear what they sound like before you go and buy them? I'd like to do a fire engine siren and horn for my son's fire truck, but I'd like to hear them before I buy them! Thanks!

 

[kchriste]

Hi. Does anyone know if there is a site out there, or a way to listen to the different sounds of piezo buzzers so you can hear what they sound like before you go and buy them?

Not that I know of. You certainly won't be able to tell how loud they are.

I'd like to do a fire engine siren and horn for my son's fire truck.

I would think twice about that. Besides it being very annoying to yourself and the neighbors, studies have shown that children today are suffering from hearing loss due to loud toys. A young persons ears are more prone to hearing loss from high DB sound levels than an adults.
If you insist on putting a siren/horn in the truck, use a speaker and a swept oscillator for the siren. That way, different sounds could be produced and a volume control could be fitted as well.

 

[Boncuk]

I gave my son a drum as a Christmas gift. One week later I gave him a pocket knife to find out where the sound comes from.

 

[audioguru]

A piezo "buzzer" has a 3kHz oscillator built-in. It beeps at a single high pitch when it is powered from a DC voltage.
A piezo transducer is a tweeter speaker. It plays variable high frequency sounds when fed from an amplifier.

The fire engines in Canada do not sound like a beeping smoke alarm nor like a tweeter speaker.

 

[ericgibbs]

Hi. Does anyone know if there is a site out there, or a way to listen to the different sounds of piezo buzzers so you can hear what they sound like before you go and buy them? I'd like to do a fire engine siren and horn for my son's fire truck, but I'd like to hear them before I buy them! Thanks!

hi,
Google for; fire engine sound downloads

**broken link removed**

**broken link removed**

 

[crazyfazy_7]

Thanks for all your advice and comments! I just put a flashing strobe circuit with white/red leds for head lights and tail lights on the truck for him. The truck has kind of a lame siren already on it, I just wanted it to have something a little more realistic.

[/QI would think twice about that. Besides it being very annoying to yourself and the neighbors, studies have shown that children today are suffering from hearing loss due to loud toys. A young persons ears are more prone to hearing loss from high DB sound levels than an adults.
UOTE]
I guess your right....I have to remember that the truck's for my son...not me. Sometimes I just can't help myself...I just have to modify stuff.

 

[ericgibbs]

Thanks for all your advice and comments! I just put a flashing strobe circuit with white/red leds for head lights and tail lights on the truck for him. The truck has kind of a lame siren already on it, I just wanted it to have something a little more realistic.

[/QI would think twice about that. Besides it being very annoying to yourself and the neighbors, studies have shown that children today are suffering from hearing loss due to loud toys. A young persons ears are more prone to hearing loss from high DB sound levels than an adults.
UOTE]
I guess your right....I have to remember that the truck's for my son...not me. Sometimes I just can't help myself...I just have to modify stuff.

Did you try my Fire Truck sound link.????

 

[Suraj143]

Hi I have a piezo transducer it needs some pulse to generate a sound.

My problem is what frequency & duty cycle I have to supply?

Data sheet is not available typically what frequency do I have to supply?

 

[kchriste]

Is it a 3 wire one or a 2 wire?

 

[Suraj143]

Its two pin here is a picture

 

[kchriste]

Assuming they don't have a built in driver. ie: they "click" when connected to DC:
Typically they operate around 3-5Khz. You could simply drive them with a signal generator and listen to see at what frequency it sounds the loudest. To be more accurate you'd need a sound level meter. It is perfectly OK to run them at other frequencies, but they just won't be as loud or efficient.

 

[Suraj143]

Assuming they don't have a built in driver. ie: they "click" when connected to DC:
Typically they operate around 3-5Khz. You could simply drive them with a signal generator and listen to see at what frequency it sounds the loudest. To be more accurate you'd need a sound level meter. It is perfectly OK to run them at other frequencies, but they just won't be as loud or efficient.

Totally understood.Thanks for the help.I'll give 3-5Khz & see with a 50% duty cycle.

 

[audioguru]

The plastic housing is a resonant cavity that will make it loud at a single frequency.

 

[Suraj143]

Hi audioguru thanks for the info is it ok if I drive the above piezo with 100Hz?

 

[Torben]

Hi audioguru thanks for the info is it ok if I drive the above piezo with 100Hz?

It's hard to tell from the photos but I'm thinking that those things are about 1.5 cm diameter and the centre hole is about 2 mm diameter. That makes me think that 100Hz would be really low for it. I'd think higher, like in the 1kHz or more range. Not sure exactly but if you have a datasheet or if you can report its actual model number or any more information about it, it will be easier to work out.

I looked on the lianhuabuzzer site and did not see any photos which matched what you showed in your earlier post.

Another way to check would be to make a simple 555 or PIC square wave frequency sweep generator and check where it sounds loudest. That won't be exact but it would give you a general idea of what might work.


Good luck,

Torben

 

[audioguru]

Here is the frequency response of a similar piezo transducer. There is no output below 1kHz, a huge peak at 5kHz, a huge notch at 8kHz and generally horrible flatness to the response.
I call it a whistle.

 

[Hero999]

Some piezo transducers have a sharp resonant peak at about 30kHz which makes them very useful ultrasonic transducers.

 

[elfcurry]

I have several of these but just the two concentric discs without the plastic housing. I imagine that these need to be mounted on something solid to get any noticable sound; is that right?

How should I drive it? Does it just appear as a capacitor? Can I just connect it to a micro port pin (I'm thinking 8051, not PIC with higher current drive) without damage, or do I need more current drive, protection or current limiting resistor?

TIA

 

[audioguru]

Try driving the piezo transducer directly from a little power amplifier like an LM386 or make your own amplifier. The output current from a 8051 is almost nothing. If you space the piezo a short distance from a bottle cap then the cap becomes its resonant cavity which will make it loud at one frequency.

 

[Hero999]

The best way is to use two outputs, one the inverse of the other which is equivalent to a bridged amplifier output and will give four times the power and double the loudness of a single output to 0V.

Because piezos are high impedance devices, you'll get more power from a PIC run off 5V using two ports than you will from an LM386 using the same voltage.

I resonant cavity helps and it's possible to build one. You'll need a piece of plastic pipe about the same diameter as the silver foil (nromally about 18mm) disc on the back of the transducer. Cut it to about 5mm long so it forms a hoop. Drill a 5mm hole in the enclosure were you want to put the piezo. Glue the plastic ring to the enclosure and the piezo to the hoop.