Alarm circuit help

M

MarEll

New Member

• Dec 8, 2009

• #1

Hi

Could anyone give me any tips on creating a circuit that would - when given 12v - beep a buzzer (for example) for a short period then pause for approx 10 seconds, repeat then go silent until the 12v is removed and re-applied?

 

M

MarEll

New Member

• Dec 9, 2009

• #2

No takers?

Could this be achieved with 555 timers?

 

Dragon Tamer

Member

• Dec 9, 2009

• #3

this could esily be acheived using 3 555 timers. I've done it before, if I can find the circuit diagram then I will post it for you.

 

Z

zhyh000

New Member

• Dec 9, 2009

• #4

hello,
you can use a 555 timers to have a try,T=(R1+2*R2)C*ln2=10 seconds, change the dutyfactor with R1 and R2, D=(R1+R2)/(R1+2*R2)
R1 is between VCC and Pin7, R2 is between Pin7 and Pin2

 

Last edited: Dec 9, 2009

M

MarEll

New Member

• Dec 9, 2009

• #5

Cheers Dragon, that would be great.

I just had another go at it but got no joy.