Bi-tonal Siren (555) beginner project problem

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Emile Binot

Joined May 22, 2017
2
Hello,
I tried to do this project on my breadboard but it does'nt work (i'm a beginner).
I just replaced the 33k resistor by a 47k resistor because I didn't have one.

The output signal is on the 3rd pin of U2 right ?And I should hear 2 tones like a siren no ? ( right now i hear nothing)
Is there something wrong on this schematic or something badly indicated ?
thank you
 

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Colin55

Joined Aug 27, 2015
519
HEE HAW SIREN with one 555

The flashing LED is used to provide the timing and also to alter the 555 to produce two different tones.

 
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