How to raise an alarm for Unauthorized Entry
Step 1: Understanding the Elements
Intruder Alert- Raising an Alarm for Unauthorized Entry
Starting Conditions: Smart House is not secured.
- Door Detector 1 (Bit 78)
- Door Detector 2 (Bit 79)
- Motion Detector (Bit 258)
- Alarm Keypad- Armed (Bit 82)
Output: Siren (Bit 58)
Connect I/O Functions to be used
- SR- SET RESET
Step 2: Connect I/O Solutions:
Step 3: Description of the Functions Used: Door Detectors
Door Detectors 1 (Bit 78)
Door Detector 2 (Bit 79)
Door detectors are installed to detect the position of the entrance door. The corresponding bit is ON if the door is closed & OFF when the door is OPEN. So it performs Boolean operation
BIT 78 represent Door Detector bit for Left Door & BIT 79 represent Door Detector bit for Right Door.
Step 4: Motion Detectors 1 (Bit 258)
A motion detector is a device that detects moving objects, particularly people. A motion detector is often integrated as a component of a system that automatically performs a task or alerts a user of motion in an area.
We are using Motion Detector to raise the Alarm when the home is secured by the password
Step 5: BIT 82: Alarm Keypad Armed
This is an Alarm unit which is used for Home security purpose. When user enters the default password, it gets armed. And we get the feedback of armed situation by BIT 82. This Bit gets ON when Keypad is armed & gets OFF when Keypad is unarmed. The Keypad can be unarmed by entering the correct password again.
Step 6: BIT 58: Output Siren
This is an Alarm Bit type Output (Boolean), when this BIT 58 gets high input, it raises an Alarm in the Smart House
Step 7: 2 Input AND Function
This function gives TRUE (or HIGH)
output when both of its Input (IN1 & IN2) are TRUE.
If any of the input is false, Output is false
Boolean Expression: OUT1 = IN1.IN2
Step 8: 2 Input AND Function
This function gives TRUE (or HIGH)
output when either or both of its Input (IN1 & IN2) are TRUE.
If both of the inputs are false, Output is false.
Boolean Expression: OUT1 = IN1 + IN2
Step 9: NOT Function
This function gives TRUE output when Input is False.
If inputs is false, Output is TRUE.
It is also known as “Inverse” Function.
Boolean Expression: OUT1 = IN1
Step 10: SR: SET- RESET BLOCK:
This block is used to Latch/Unlatch the output such that, on receiving the pulse at SET- It will hold the Out Terminal permanently, until it receives Pulse at RESET. This is SET dominant function, which means, if Input is applied to both SET & RESET Terminal, this function unlike RS block will SET the output
Step 11: Explanation of Solutions:
INTRUDER ALERT- RAISING AN ALARM FOR UNAUTHORIZED ENTRY
In the Connect I/O Logic,Here we have to raise the alarm on the following 2 situations:
IF EITHER OF THE DOOR IS OPEN AFTER KEYPAD IS ARMED
Door opening will be sensed by Door detector 1 (Bit 78) & 2 (Bit 79). We need an output if any of the Bit is High so we have made a NAND Gate by combination of AND & NOT, which is further given to Input of AND Gate & the other input is given Alarm Keypad Armed Bit
IF MOTION DETECTOR DETECTS ANY MOVEMENT AFTER KEYPAD IS ARMED
Motion Detector Bit 258 is AND with Alarm Keypad Armed bit.
The outputs of the above two independent AND Gate are given to Input of OR Gate & is further used to Latch the Siren via SR Block. By doing that, Alarm can be raised if any of the above situation gets TRUE.
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