Simple circuit alarm home

Be covered in a simple alarm House for those who are eager to know the concept of switch are homeland security system. Consists of three 555 timer gets input, which can be linked to a motion sensor, or monitors any current contact a specific process. Once the contact is closed temporarily, first timers is configured as output MONOSTABLE prints lasting boost to a maximum of 220 seconds.

This output is fed on second timer as a height adjustment 1 Hz square wave generator is the output of configured.proi this second clock is then third timers frequency modulation frequency modulation control eingespeist.Diese is a presenter and a similar as the police siren to generate the siren sounds.

First timer U1 is configured as a monostable with variable timing up to a maximum of 220 secondes.Calendrier timer by adjusting the VR1 - ohm potentiometer 1 modified M unless you need for improved calendar, E1 bipolar electrolytic to a higher value may be modifié.Une times contact CT is temporarily closed, generates an output pulse U1 3 axis.

U1, then feed the question timer Reset PIN U2 U3 4 and two timer its tasks with height adjustment mode to start U2 oscillator is configured as a square wave close to 1 Hz adjustable in height, set values for E3, R2 and R3.

[(f = 1, 44 [(R2_+_2R3) (E3)])]

[(= 1, 44 (10) [(10__+__2_*_82)] _Hz)]

= 0.8 Hz

U2 timer output is used to control the voltage feed where suspended ist.Diese R6 resistance frequency modulation frequency modulation U3 timer generates a sound similar to police Sirene.Die frequency this tone generator can changing the potentiometer value VR2 save their maximum 220 ohm k has changed, is a tone in 320 Hz output U2 update is used, a transistor makes fahren.Diode D2 used to damage transistor T1 and back emf generated by the speaker to avoiding ON, OFF-take the speaker 8 ohm speaker.

The alarm circuit Assembly parts list

More information: transistor photo detector