how much stong is the sound?

A

alexthefox

Senior Member
hello,
in manual3, at page 10 there is interface with a speaker.
my question is:
how many Db can do this?
i need something around 100 Db, i suppose it cant do.

what can i do to have this result?
thk
 
hippy

hippy

Ex-Staff (retired)
A simple speaker across a PICAXE output pin isn't likely to deafen someone. You can increase volume by using a bi-phase signal or you can increase the volume by amplification.

Filter the signal and use suitable amplification and you can have it as loud as you want - right up to Disaster Area levels ( HHGTTG, Douglas Adams ), level 12 on a Spinal Tap scale.
 
D

Dippy

Moderator
"i need something around 100 Db, i suppose it cant do."

Well, 100dB... at a distance of 1cm or 1km?
Headphones or 30cm woofer?
Frequency range desired?

If you CRC your output signal (AC coupling then filter off nasty squre edges) then feed an audio amplifier you can get what you want as hippy alluded to above.
If you want to drive anything more than a tiny speaker at a decent power you will probably have to supply a lot more than 5V to the speaker.

The minimalist may suggest a home-brew using one or more transistors. I wouldn't bother as there are a zillion audio amplifier available. These range from ic chip size devices (some SMD like TI's TPA1517), through various modules with heat-sinks right up to PA system monsters.

Having said that a transistor amped piezo (in resonant enclosure) may give a satisfying sound over a limited F range and at shot range, but it won't be much use as a burglar alarm!

The efficiency can be improved hugely by some effort from you. If you have a standard cone-type speaker dangling in mid air the output will be poor, but the same speaker in a well designed enclosure will be much, much louder and with a much better frequency response.

An example of an easy-to-use (apparently) device which could handle a small/mid sized speaker is the TDA2003 from ST. But there are many other options which you can search for yourself. And then the horrible part... you will have to read the Data Sheets :)
 
I

inglewoodpete

Senior Member
Alex, You don't indicate the purpose of your application. "100dB" is fairly meaningless if you fully understand what decibels measure: power ratios.

My understanding of what you are asking is that you want a "very loud" output.

The sound output from a PICAXE is a very harsh sounding square wave. If that is what you want, then use a power MOSFET. Connect a 0.1uF capacitor between the PICAXE output and the MOSFET gate and a 4.7k resistor between the gate and 0v. The MOSFET source should connect to 0v, too. A high powered speaker can be connected between the MOSFET drain and a +ve supply. Initially, try a 12 volt supply on the speaker. This could be increased to 25 or 35V if you need it louder. A rough but simple solution to "loud PICAXE".

Note: the PICAXE must be powered from 4.5 or 5volts!
 
A

alexthefox

Senior Member
inglewoodpete said:
Alex, You don't indicate the purpose of your application. "100dB" is fairly meaningless if you fully understand what decibels measure: power ratios.

My understanding of what you are asking is that you want a "very loud" output.

The sound output from a PICAXE is a very harsh sounding square wave. If that is what you want, then use a power MOSFET. Connect a 0.1uF capacitor between the PICAXE output and the MOSFET gate and a 4.7k resistor between the gate and 0v. The MOSFET source should connect to 0v, too. A high powered speaker can be connected between the MOSFET drain and a +ve supply. Initially, try a 12 volt supply on the speaker. This could be increased to 25 or 35V if you need it louder. A rough but simple solution to "loud PICAXE".

Note: the PICAXE must be powered from 4.5 or 5volts!
Click to expand...
i need to have sound like piezo buzer, but with a different choice of frequency. buzer can do 100 or more Db at 1mt. but with fix "sound". i need to have something like this but with the possibility to have different sound. hope you understand me. i need this extra circuit small, like a buzer + or -
 
D

Dippy

Moderator
Mmmm.. what's wrong with all the suggestions made?

A piezo peeper/buzzer has , as you know, a built in frequency generator. The frequency the manufacturers choose corresponds to the resonant frequency of the element+cavity (shape/size & sound hole) of the device.
Hence it is pretty loud, because it is designed to resonate at that frequency.

If you want a small sounder (i.e. a tiny loudspeaker) where you can input various frequencies there are compromises.
You can buy a small transducer like this example:-
http://www.rapidonline.com/netalogue/specs/35-3605e.pdf

Look at the graph, see the F response. See the resonances. Up and down the little line goes...
You will have to 'drive' this device with the afforementioned simple electronics.
BUT, you should understand that the output dB will vary depending on the frequency. Look at the graph Y axis.

You could use a standard loudspeaker if you can stand the size. Again they will have resonances and YOU will have to make the box into which it is fitted. The overall performance will depend how you drive it i.e. the electronics/amplification you use. A larger transducer in a larger enclosure will tend to give a more even frequency response.

I have never seen a small PCB-mounting type sounder with built-in amplifier. Perhaps they exist on Ebay?
 
W

westaust55

Moderator
Piezo Speaker

Firstly, there are piezo buzzers. These put out a single frequency when a voltage is applied. Not much more other than use PWM you can try to use on them.

Second there are piezo speakers. These are much the same as a normal speaker but the signal must be oscillating for them to operate. There is no output with straight 5Vdc applied. Then you can have a wide range of frequencies. Draws virtually no current at 5Vdc.

Here in AUstralia, MicroZed are the primary PICAXE agents. They sell a piezo speaker. Part PZ002 for AUD$3-50 each. It is 9cm diameter and 4cm high with solder terminals.
see: http://www.microzed.com.au/beepers.html

I bought one of these and it has better volume that a 3cm piezo speaker and to my ear better tonal quality as well considering the square wave output of the sound command from the PICAXE. sound pressure level is unknown to me but suggest around 80dB(A).

For something about the same size capable of operating on up to 20Vdc (you will need a transistor/amplifier interfact) and 90dB(A)/ (96dB(B) look at:
http://tronstar.manufacturer.globalsources.com/si/6008802209521/pdtl/Hi-fi-speaker/1000743798/Piezo-Tweeter.htm/ Plent of others on this same site.
 
D

Dippy

Moderator
Alex, are the above suggestions anything like what you require?

If not, can you supply a more detailed description of what you want?

I only ask as I'm starting to see echoes on this thread :)
 
M

moxhamj

New Member
A

alexthefox

Senior Member
Dippy said:
Alex, are the above suggestions anything like what you require?

If not, can you supply a more detailed description of what you want?

I only ask as I'm starting to see echoes on this thread :)
Click to expand...
yes and no...i want to check all info from users of this fantastic forum.. i want check the best way to do what i need...
thank you again
 
I

inglewoodpete

Senior Member
Piezo sounders can be operated with 2 or 3 PP3 9v batteries (ie 18 or 27 volts) to get a louder sound. In my younger days when umpiring volleyball matches, I used 2 piezo sounders (the ones with built-in oscillators) and 2 x 9v batteries, all mounted in/on a small plastic case. Due to differences in the tolerances of the 2 oscillators, the 3kHz tones would beat together to give a more piercing sound.

Some clever design work with 1 or 2 08Ms driving 1 or 2 basic piezo 'speakers' (the ones without the internal oscillator) through a MOSFET could give you what you want.
 
D

Dippy

Moderator
"i want check the best way to do what i need"

Well, what do you need?
You've mentioned 100dB and implied @ 1m. That's fairly clear.

You haven't mentioned size restrictions (if any), frequency response, any power supply/battery limitations (if any), budget etc.
 
M

Mycroft2152

Senior Member
Dippy said:
"i want check the best way to do what i need"

Well, what do you need?
You've mentioned 100dB and implied @ 1m. That's fairly clear.

You haven't mentioned size restrictions (if any), frequency response, any power supply/battery limitations (if any), budget etc.
Click to expand...
Dippy,

Misplaced your crystal ball today?

Myc
 
A

alexthefox

Senior Member
Dippy said:
"i want check the best way to do what i need"

Well, what do you need?
You've mentioned 100dB and implied @ 1m. That's fairly clear.

You haven't mentioned size restrictions (if any), frequency response, any power supply/battery limitations (if any), budget etc.
Click to expand...
i wrote dimension like a buzer plus or minus... power supply 12V. frequency range is not really importantant. i will do something like a buzer where i can sound different frequency from 1,5 to 3 KHz
 
D

Dippy

Moderator
"i wrote dimension like a buzer plus or minus"
- Mmmm... Buzzers/sounders come in sizes from 6mm diam to 40mm diameter (and square) for standard PCB stuff. Obv you can get special mini ones for s/m. Obviously you can get bigger ones on leads.

If you want to have a sounder/transducer to generate your own frequencies you will have to allow some space for your driver/amp. This could vary from a single transistor type to an I.C. based amp which needs a couple of extra components.

In the hour I have spent looking I cannot find one with a built-in amp, perhaps someone has some time to spare to look or has seen one? I'm sure some enterprising manuf makes them?? The Beijing Buzzer Company maybe? (I couldn't quite understand the Mallory/Transducers (No circuitry)/self-drive?)

I have yet to find a small pcb style transducer/sounder which gives a spec anywhere near your required 100dB at 1 metre. I have only looked at about 20 data sheets.
You may get ~100dB @10cm @12V with this one:-
http://www.farnell.com/datasheets/87252.pdf

You'll likely get a nice loud one if you don't mind a larger device. Or you might strike lucky.

I'll leave you to look. I'm sure you'll find something appropriate sooner or later.
 
D

Dippy

Moderator
Myc:
Crystal ball?
I'm sending mine back to Ebay, it obv doesn't work.

By the way, how long is a piece of string?
 
W

westaust55

Moderator
how much stong is the sound

[qoute]
By the way, how long is a piece of string?
[/quote]

Ans: twice the distance from the middle to one end :D

As for sounders, members have given Alex various suggestions.
Think it is now at a point where our knowledge is given baring others doing the research. Alex needs provide a clear specification or do some research himself.
 
A

alexthefox

Senior Member
westaust55 said:
[qoute]
By the way, how long is a piece of string?
Click to expand...
Ans: twice the distance from the middle to one end :D

As for sounders, members have given Alex various suggestions.
Think it is now at a point where our knowledge is given baring others doing the research. Alex needs provide a clear specification or do some research himself.[/QUOTE]
yes, you say the true. im read here and myself try to find other solution. thank again all member of this forum
 
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