Car Wireless Alarm

  
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This FM radio-controlled anti- annexation anxiety can be acclimated with any agent accepting 6- to 12-volt DC accumulation system. The mini VHF, FM transmitteris adapted in the agent at night back it is anchored in the car balustrade orcar park. The receiver assemblage with CXA1019, a distinct IC-based FM radio module, which is advisedly accessible
Car Wireless Alarm - schematic

in the bazaar at reasonable rate, is kept inside. Receiver is acquainted to the transmitter`s frequency. Back the transmitter is on and the signals are actuality accustomed by FM radio receiver, no hissing babble is accessible at the achievement of receiver. Appropriately transistor T2 (BC548) does not conduct. This after-effects in the broadcast disciplinarian transistor T3 accepting its advanced abject bent via 10k resistorR5 and the broadcast gets energised. Back an burglar tries to drive the car and takes it a few metres abroad from the car porch, the radio articulation amid the car (transmitter) and anxiety (receiver) is broken. As a aftereffect FM radio bore gene-rates hissing noise. Hissing AC signals are accompanying to broadcast switching circ- uit via audio transformer. These AC signals are rectified and filtered by diode D1 and capacitor C8, and the consistent absolute DC voltage provides a advanced bent to transistor T2. Appropriately transistor T2 conducts, and it pulls the abject of broadcast disciplinarian transistor T3 to arena level. The broadcast appropriately gets de-activated and the anxiety affiliated via N/C contacts of broadcast is switched on. If, by chance, the burglar finds out about the wireless anxiety and disconnects the transmitter from battery, still alien anxiety charcoal activated because in the absence of signal, the receiver continues to aftermath hissing babble at its output. So the...



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