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# an annoing device(?!)

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#### bogdanfirst

##### New Member
well i need a device to make an annoing sound, for more things to ue on:
i sellp very well, and even if o modified a clocl to sound 10 times louder ir is not strong enough to wake me up, so i want to make a douns generator with a very announg sound, wich will make noise for 1 minute.
the other thing i need it for is to prevent people and animals to going in a room, to sound when someone comes there.(i got the triggering device) but the first use is more important.
now, what i thought of is a high frequency sound, with great power, but having a strong sound will wake up people from other rooms, so i want something annoing but not so loud.
i wait for your ideas, on this circuit, and also for other ideas to wake up a sleepy persson.

#### Gene

##### New Member
How 'bout a recordable sound chip on which you have you Mom record, "Hey bogdanfirst, get up NOW!" feed this into a small audio amp and have the feed repeat every 20 seconds until you get out of bed, walk across the room, and shut it off.

#### bogdanfirst

##### New Member
this is what i have, from what i remember the big one can give up to 100dB.
but i still need to make a driving circuit. i still think about the frequency. i think i am going to use a circuit with 2 555 timers, one for the sound generator and one for making the beep-beep...effect.
but i think i need a transformer for driving the buzzer wright?
still, i think of some other ideas.

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#### kinjalgp

##### Active Member
No the transformer is not necessary. Check out this circuit: **broken link removed**

#### Gene

##### New Member
Not necessarily. If you go with a 555, it sounds like you are trying to drive a speaker. On the other hand, pezio buzzers come two ways (those that require an external circuit and those that do not).

#### bogdanfirst

##### New Member
well i just have a simple buzzer, with no feed back. i dont know why but they are hard to find here, seems that nobody needs them.
so the circuit i will have to design must be for a buzzer with no feed back...

#### Sebi

##### Active Member
Few years ago ive tryed out several piezo buzzers as datasheet says: with max.20Vpp. All sounds was above similar. Also tryed several built-in electronic types with better loud. Only one type give 120dB with 12V 130mA: it contains a transformer and supplyed to piezo 300Vpp!
Ive think this is a spec.type piezo, but when i changed it an other (20Vpp) type, (for fun,i`ve think maybe exploded) it work fine and loud!

#### Gene

##### New Member
Oh well. Back to the 555 idea. Construct as an astable oscillator, connect pin 3 to a 10 mdf electrolytic (+ to pin 3), the other side of the capacitor goes to a speaker. The other side of the speaker goes to ground. Now, design the R-C pulse circuit on the front side of the 555 to an audio range frequency. You will probably want to replace the speaker with a little audio amp to get really loud. The resistor between pins 6 and 7 of the 555 should be a variable type so you can find the "perfect" pitch.

#### bogdanfirst

##### New Member
wooooooouuu!
first, i know how to build an oscilator with a 555. my question was mainly what frequency to choose to be very annoing....
i thought that around 10-12KHz, or maybe even up to 12KHz
i have a door alarm, the one that sounds when the door is opened. it uses a buzzer like the one i have and it has got a transformer with a 5R primary and a 120R secondary(connected to the buzzer). it is powered from 3 1.5 V cells and is says it can give 118dB. it will be nice if i could generate the frequency i said with a constant tone with a power of sound of around 100dB
so, thanks since now, but i still want more ideas before i decide upon one idea.

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