Multitone Siren Alarm

Electronic Siren based NE555
Here the circuit diagram of electronic siren based NE555. This circuit produces a sound like factory siren. It applies a 555 timer IC which is utilized as an astable multivibrator of a center frequency of about 300Hz. The frequency is controlled by the pin 5 of the IC. When the ... British Police Car Siren
This is the sound generator which will simulate British police car siren. The circuit is built using 2 pieces of timer IC 555 to generate sound frequency. How the circuit work: The 555 on the right is wired as an alarm sound generator and the second 555 timer on the ... Sound Effect Generator UM3561
This is a really simple sound effect generator based single sound generator chip UM3561. The UM3561 will generate four kinds of sound effects. The basic operation is that the UM3561 will generate the sound signal, then the signal delivered to 2N3706 (as speaker driver) to be amplified so you can ... Wailing Alarm Siren
Here the wailing alarm circuit diagram: Component parts List: R1,R5___________ 4.7K R2______________ 47K R3______________ 10K R4______________ 100K Rx______________ *see text C1,C4__________ 100uF/25V, electrolytic C2,C3__________ 0.01uF (10nF), ceramic T1_____________ 2N3702 (NTE159, TUP, etc.) IC1,IC2________ LM/NE555, MC1455P, etc LS_____________ Loudspeaker *The Loudspeaker LS and the resistor marked "Rx" should be together 75 ... Easy Build Motorcycle Alarm
The following circuit is a simple, cheap and easy build motorcycle alarm. The circuit just required 2 transistors to drive the relay the the relay act as a switch to activate the buzzer. Any number of normally-open switches may possibly be applied. Fit the mercury switches to ensure that they ...