555 Siren

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This instructable will show how you can create your own siren sounding circuit.

In this two 555 timer ic's were used
the first one is operating in Astable mode ( ie output is switching between high and low without any intervention from the user ) and is used to designed such that to produce a low frequency

well the second one also operating in Astable mode but it is driven by the output of the first timer by using the control voltage pin 5 .Due to this up and down in the control voltage it produces a wailing sound

You can also produces some different sound like Ambulance , Police Car , Alert Alarm etc by changing the frequency of the first timer all you have to do is to change different resistance by using the potentiometer
and try some different valued electrolytic capacitors ...

Step 1: Components List

These electronic component are easy buy and very cheap

1. NE555 timer ic (2)
2. 10uF electrolytic capacitor (2)
3. 100nF Ceramic capacitor (2)
4. 10k resistor (3)
5. 1k resistor (1)
6. 68k resistor (1)
7. Speaker 0.5 watt OR any (1)
8. 9v battery and clip (1)
9. One small breadboard (1)
10. Some jumper wires....

Step 2: Placing Jumper Wires

Place all the jumper wire in the sequence i follow OR make your own breadboard connections...

Step 3: Placing Resistors

Place all the resistor as shown..

Step 4: Placing Capacitors

now after that. place all the capacitors ...
you can also change the capacitors values for the different taste of sounds

Step 5: Placing a Speaker and a Battery

Be careful about the speaker connections the negative of speaker is connected to the ground while the positive is connected to the negative of the electrolytic capacitor as shown in the schematic....

Step 6: Working Video

Don't forget to check the siren sound



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    2 Discussions


    6 months ago on Step 6

    hi i had a few questions when you can add a potenciometer to picth, volume and oscilation?


    2 years ago

    Very cool, this looks like a fun little project! :)