There is a receiver and a transmitter at entry gate,if anybody passes then alarm starts ringing.Here it is assumed that intruder don’t know basic mathematical operations(addition ,subraction ,multiplication, division). system Will ask him to enter result of given mathematical operation ,If he enters correct answer,alarm stops.
Required hardware :
8085 UP,RAM 62256P ,EPROM 27256, LATCH 74HCT573N,DECODER 74HCT138N,BUZZER, LCD 16*2, LED 5MM,3MM, NOT GATE 74HCT04N , SWITCH 10-XX , CRYSTAL 4 MHz ,CONNECTORS, RESISTORS 10K,1K ,126 ohm ,CAPACITORS 0.01uF, 10uf.
It consists of two circuits:
1. One that has an laser transmitter and LDR receiver. This circuit triggers an alarm if the laser light beam is intercepted.
2. A second one that turns off the alarm
1) The project consists of twelve switches. Ten switches for enter 0-9 digit and remaining two switches for enter and clear.
2) The project consist LDR as receiver and laser as transmitter.
3) An LCD has been used for display random number and operation.
4) The project also includes alarm for ringing to indicating intruder enter at gate and turn off when he /she knows the answer.
5) There is also a provision for SID/SOD and RESET using switches.