Electronic car antitheft alarm - has three time delay circuits operated by door pillar switches with alarm isolating ignition coil and activating horn and lights

摘要

The electronic car alarm uses three time delay circuits. The first is brought into operation by a door pillar switch which allows the driver 30 secs. to open the car doors without activating the alarm. A second delay then allows 10 secs. in which to switch on the car ignition when the car doors have been closed. If either time interval is exceeded, the alarm is activated and the horn and lights sound and flash for 30 secs. intermittently. The intermittent action is controlled by separate multivibrators for horn and lights, which are provided by relays. The alarm also isolates the ignition coil.