This project is about an 8051 microcontroller based home burglar alarm system using PIR and Magnetic Reed Switch sensors. The circuit detects motions using the Magnetic sensor and also detects living things using the PIR sensor. When an intrusion occurs, password verification is requested and if it answers incorrectly, there is a security violation. A warning signal is sent through serial communication when this situation happens.
There are many different ways to send an warning signal with serial comm. You can send SMS with the GSM module or make different applications. I used TCP/IP comm for warning signal. When there is a security violation, 8051 microcontroller sends '1' signal to serial port. Then, my Python client code gets these signals. When the received signal reaches every 3 times, a warning message is sent by Python to the Police server. For given example to this scenario, I made these client and server code with Python.
- S1 - Security Violation and Sending Warning Signal
- S2 - Alarm Disabling
- S3 - Incorrect Password
- S4 - Password Reset
- S5 - Reset Button
- AT89C52 Microcontroller
- PIR Sensor
- Magnetic Reed Switch Sensor
- LCD Panel
- 4x3 Keypad
- Buzzer
- LED
- COMPIM (Its up to you what do you want using for sending warning signal like GSM module)
- Crystal (Important for serial comm!)
If do you want to using serial comm with 8051 microcontroller you have to assign Crystal frequency. Its depends serial comm Baud Rate value. Baud Rate value determines the serial communication speed of the circuit and if not determined correctly, warning signal will not be sent. Here this website explain everything about calculation Crystal frequancy and Baud Rate relationship.
Commonly thing, people prefer the 9600 Baud Rate, and this gives the result equal to 11.0592MHz for the Crystal frequency. I generally prefer 24MHz for 8051 family because of its convenient the machine cycle calculation. Equation is below and it shows my Baud Rate value equal to 20833.
