Anti-theft control circuit for car - uses car radio as amplifier and warning signal complete with coded setting switch

摘要

The car radio is connected to the anti-theft control unit and it coupled to the battery through a common fuse. The last stages of the radio, e.g. the amplifier and loudspeaker, are used in the anti theft device. The anti-theft sensors activate the control unit which then produces a signal tone for the radio, which is repeated on optical and acoustic warning devices. The unit has a logic control comprising impulse generators and shift registers and bistable switches. The system is activated and switched off by coded switch operation on the radio and is tested using the indicator lamps for the radio. If the lamps are lit then both radio and unit are functioning.