Make your own free website on
Hi-Tek Intruder's Alarm

History / Background
Photo Album
Instructions Page
Related Links
Contact Me

Hi,I am R.Mahesh. I am at present doing my Master's degree in Information Technology at St.Peter's Engineering College affliated to Anna University, Tamil Nadu, India.
I have great interest in the field of programming and robotics. My first project was on a small program with an unit more likely a robo car.The car works with the help of a computer program. The unit is controlled by the commands entered by the user. Another small AI program included helps the program to plan it's way of action.
Now my project on 'Hi-Tek Intruder's Alarm' is ready for use. My plan was to create an instrument that might alarm me when some intruder is at my home through my mobile. My theme was to make it easy and efficient. I wanted to implement things easily. So the project was planned and discussed with my friend.

As I am a student from computer science background, I was able to plan the thing efficiently but could not help my self in the field of electronics. So I had to sort my friend's help too.
The plan was to be carried out in three phases.

1.Communication Phase
2.Detection Phase
3.Connection Phase
In the Communication Phase, I needed an instrument to be used to alarm me when an intruding happens. So to make the communication possible to the particular number, the usage of the buffer memory was essential. It must have the capacity to hold the data or the number I am going to feed in it for some time or say for some days. The best solution I found was to use the telephone itself where it has it's own small buffer. So the test on the communication phase was carried out and it became a positive output.
The Detection Phase we had to work better to have a perfect and accurate output. Here the plan was to
use two counter's. So two 555 Timer IC's were used to help us hold the pulse for some time. One IC holds the current pulse for 5 seconds and the other for 90 seconds. We must use this 5 second current pulse to initiate the buffer memory of the telephone and the 90 seconds current pulse to hold the telephone line. Now the latter pulse helps us to dial the number stored in the buffer memory while the telephone line is held by the other timer IC.These two operations are performed as soon as the Laser beam is intruded inbetween which is on it's emission from the emitter to the reciever.
The third phase was to link the above two phases. An electronic switch is used to open and close the connections with the telephone buffer and the memory. After a week of planning, designing and implementing this circuit became a successful one.

According to me the above design for the instrument is so simple that it can even be done as projects. It costs less than 1000 rupees.  For further clarifications you can send mails to


Circuit Board Picture

I like to thank my friends and all those who encouraged me in my work.
"My work is a tribute to Kalpana Chawla, my role model"