This is an informal project done with help of Arun Prasad and Sreejith Sir. The project aims at detecting an intruder in a secured environment. For these we use PIR ( Passive infra-red Sensors ) and Independent Xbees. Independent nodes were used. Custom PCB designs were made to sustain an Xbee module, PIR sensor and a 9 V battery. The Xbee was used in sleep mode to consume less power. The PIR sensors were used because they are digital sensors. They were bought from Nex Electronics, Bangalore. One pin of the Xbee was configured as input for the PIR sensor. The same pin was ‘not’ed and used as a Sleep Pin. This type of configuration saved a lot of battery power.
A web portal was developed for the same. The user had the flexibility to switch on or off a sensor node.
Two way communication between sensor node and co-ordinator node was established. The sensor node sent data to the co-ordinator only when it detected any motion in its surroundings. The user is intimated by sms and email using the web portal. The sensor node sends data to the co-ordinator which is then connected to a server. Real time updates on the server are reflected on the portal using an interactive map which displays the point where the intruder was detected. All this was established using web development. And frankly, I suck at web d. I concentrated on the communication between different nodes from the Xbee to the co-ordinator and sending data to the server in proper format from the co-ordinator node.
The entire system was independent and deployed in the CS dept. of our college and it responded well.
A key point here was to identify the source of the data, ie we need to know which PIR sensor was activated. We used remote AT commands to configure them. Kindly email me to know the exact commands used for the same.
We used a Java serial communication interface to communicate between the server and Co-ordinator node.