Posted by Swagatam Majumdar
We have often seen laser alarm system as an integral part of security solution especially for a location which deserves hi-level security.
Right from a museum preserving priceless historical possession; to a safety bank vault; and even in thriller flicks where the protagonist is seen on and often tied in the ray of red light beams, while trying to reach a safe vault; one is well acquainted with the usage of laser light beams. In fact it is also considered as a security device even in household today to ward off burglary or theft.
A laser beam is not a simple beam, but has the efficacy to respond when faced a distraction. This means that if the light ray gets interrupted with any objects, the photodiode receives resistance which in turn activates an alarm. The laser alarm system is an economical option when it comes to consumption of power, as the receiver needs power supply less than 10 mA on average. Setting up a laser alarm system is relatively easier as the laser and the receiver can be setup in one box, on a single power input.
Below is a circuit design diagram which illustrates the flow of a laser alarm system.
Referring to circuit diagram it is seen that a TL072 op-amp (IC1.A) is configured as a voltage comparator, placed in between the adjustable voltage driver P1/R4 and the light-dependent voltage which consists of photodiode D1 and R3 – a fixed resistor. As the laser beam receives a distraction from a foreign agent, the voltage on comparator pin drops to 2 below that at pin 3, thereby enabling the agent swing to positive voltage supply and enable an alarm situation.
As the laser alarm can detect any foreign agents, so is the alarm can be set in a more sophisticated fashion, where it can bypass accidental interrupts from agents, like an insect. This is accomplished as the Resistor R2 provides a level of hysteresis, thereby prevent oscillation when two comparator input
Bibliography: `CHAPTER I INTRODUCTION A. Background of the study This study aimed to develop a laser detector, which is able to detect unexpected visitor to prevent safety on every household. The LASER Light Activated Alarm has three main parts: a) laser, b) mirror, c) light activated alarm. This device will be developed to construct a reliable protection system. The study compares the difference of laser light activated alarm to the other commercial detector. The device will be developed to use a LASER Light Activated Alarm which has detecting diode or the photocell, which turns the device on when the photocell (sensor) detects light. The researchers want to prove that the LASER Light Activated Alarm to convertible enough to fit on any sizes of doors and windows and can be operated and assembled as easy as the other expensive devices. However, it is recommended that further test be done to really verify its efficiency. B. Statement of the Problem The researchers wants to provide the people in this country with the requirements and safe operating practices for low, medium, and high powered lasers in the classrooms, laboratories, construction sites and other locations where Class II, III, and IV lasers are placed, operated, maintained, or stored. C. Significance of the Study This device will be developed to construct a reliable protection system. The study compares the difference of laser light activated alarm to the other commercial detector. There will be several test of effectiveness of the device in terms of its ability to warn owners with the loudness of sound, amount of the energy used and percent of accuracy. The cost of the device was also considered for to prove the acceptability of the device. The device will be developed to use a LASER Light Activated Alarm which has detecting diode or the photocell, which turns the device on when the photocell (sensor) detects light. The experiment will prove that the LASER Light... [continues]