Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Police Siren Modifications

Status
Not open for further replies.

Suraj143

Active Member
Hi I made the below siren.It worked but I'm still not satisfy with the sound.

Help me to fine tune this circuit.

Note that it has not used the pin 3 of the 1st IC.
 

Attachments

  • 555 Siren.gif
    555 Siren.gif
    5.1 KB · Views: 336
Square waves usually don't sound better.

Boncuk
 
The thing is this is working speedily i need to slow a little bit.

I turn the preset but its effective in the near end.That means if I can turn the preset 180" degrees it will effect only 170" - 180".
 
Use 100µF instead of 47µF for the timing capacitor of the left hand timer IC.

It will change the frequency from 0.318 to 0.149Hz.

Boncuk
 
Hello boncuk i changed the c value to 470uf it worked with the timing that i was expected.
The txo issues are

when power up the sound is very ugly.i think this is due to the charge level of the 470uf cap.how to get a smooth sound when power up?

Still the 1st preset is effective in the near end.so its very hard to tune with a screw driver.
 
Next try 47K instead of 2.2K for the top resistor (VCC -> pin7).

470µF seems to be a very high value. Better experiment with the resistors and limit the timing cap to 100µF.

Boncuk
 
Hi I have changed the below modifications.

Please see is it ok?

When I supply it from an unregulated supply the sound is not smooth.but if I give it from a SMPS it works smoothly.

But still on first time power up the sound is very ugly.Any method to prevent this?
 

Attachments

  • Siren Mod.PNG
    Siren Mod.PNG
    10.4 KB · Views: 279
Last edited:
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top