Tele Security Alert

nThis is a PIC 16F84  microcontroller based TELE SECURITY ALERT which is capable of passing a pre recorded message through the telephone line to another phone, when the system detects any intruder.

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Laser and LDR arrangement is used as the sensor here. As soon as the intruder cuts the laser beam falling on the LDR, the system triggers the control circuits and the host telephone will be in OFF HOOK condition and will get the dial tone. After 3 seconds the system will redial the remote telephone number (the number can be changed according to the convenience of the user). Then tit will wait for the response from the remote side. As soon the telephone in the remote side is off hook the system detects it by checking the polarity reversal in the line and triggers the Sound recorder/Player circuitry and the prerecorded message is then transferred to the remote side telephone. The sound recorder used here is APR 9600.The APR9600 is a good standalone voice recorder or play back IC with non volatile storage and play capability for 32 to 60 seconds