This month I am making 3 different types of siren circuits based on the 555 timer. The first circuit simulates the siren of a British police car. It uses two 555 timers in the circuit. The 555 on the right is wired as an alarm tone generator and the second 555 timer on the left is a 1 Hz astable multivibrater. The output of the left timer is to frequency modulate the right timer. This causes the right timers frequency to alternate between 440Hz and 550Hz at a 1 Hz cyclic rate. The transistor is used to help strengthen the signal to the speaker.
Source :: http://home.maine.rr.com/randylinscott/feb21.htm
Related Links
Greater siren circuit
Security alarm
555 siren alarm
Circuit Door Buzzer by NE555 + LM386
American Police Car Siren by IC 555
Red Alert Startrek Alarm by IC 555
Water Activated Alarm by IC 555
British Police Car Siren by IC 555
This entry was posted on Friday, June 22nd, 2007 at 12:46 pm and is filed under 555, alarm systems.
