Question

principle of laser security alarm

Answer 1

They work like almost every other photo-eye detector. However a laser emits a very tight (collimnated) beam which does not spread. That allows a laser to cover a long distance easily.
The laser beam goes to a photo eye detector which detects the light. This goes to an electronic circuit which determines if the signal coming out of the detector is of appropriate strength.
If the laser light falls below a certain level (adjusted by the user) the system determines that it has been blocked and triggers the alarm. There is a certain amount of extra light in case of dust etc. The laser may be visible (usually red) or invisible (infra-red). the laser. Neither one is normally visible but the first can be seen in specs of dust, cigarette smoke, etc. Infrared lasers cannot be detected visually without special equipment like night goggles but even then it is the reflections off of dust, smoke etc.
There is usually a small delay build into the system (usually measured in thousandths of a second) before the alarm is triggered. If is this delay that is being taken advantage of when you see a character on TV put in mirrors that reflect around someone trying to sneak through. Normally the delay will not allow the beam to be blocked long enough to put in a mirror no matter how quick you are. Sorry Virginia NOT everything you see on TV is real!

Answer 2

Wireless security systems can be easily controllable through awireless remoteor a touch tone phone from any place. Here main components of the laser security system areinfrared motion sensorsand a basic alarm unit. It works based on heat detection from a person’s body in case of any security fault. Based on this alarm unit is triggered. The system alerts the security monitoring person and the local law enforcement body if required. At the same time a high pitched sound also sirens. There are two types of laser beams are available, green and infrared modules. System via an infrared module will be not visible. Another beam like green wouldbe visible to the naked eye and serve as a deterrent purpose.Laser Security System Locks Working AlongWith Circuit DiagramLaser door alarm is based on the interruption of Laser beam. The laser pointer is used as the source of light beam. If somebody tries to break the laser path, then an alarm will be generated in a few seconds. Normally laser door alarm circuit will have two sections. First one, laser transmitter is a laser pointer readily available. This is poweredwith 3 volt DC supply and fixed on one side of the door frame. The receiver will have a Photo transistor at the front end. We use L14F1 NPNDarlington photo transistoras a laser sensor. HereIC1 is used as a voltage comparator with its inverting input tied to a potential divider R2-R3. We use the inverting input to keep at half supply voltage.Working Of Laser Security System Lock Along With Circuit DiagramNon inverting input receives a variable voltage based on the conduction of T1. At the opposite door frame receiver should be fixed and should beproperly aligned to the laser beam. The laser beam illuminates the face ofphoto transistorand starts conducting the voltage. So, this keeps the voltage at pin 3 lower than pin 2 of the IC.Laser Security System Circuit DiagramBy this output of comparator remains low. Both LED and Buzzer remains off in this state. While a person crossing the door laser beam breaks and T1 cease to conduct. The voltage at collector T1 rises, the voltage at pin 3 of comparator increases and its output rises. Then LED is activated and alsobuzzer. The base of T2 is kept high by the capacitor C1 for a few seconds after the output of IC1 becomes low. The C2 gives current to the buzzer for a few seconds after T2 turns off.Laser Security SystemLASER SystemThe word LASER stands for Light Amplification by Stimulated Emission of Radiation. These are available in different types like semiconductor, infrared, GaAs laser diode. This has an energy wavelength of approximately 900 nanometers with a beam divergence of 3 million radians i.e. equal to a beam width small beam width.Laser technology products will calculate distance by measuring the time of flight of very short pulses of infrared light. It is different from the traditional surveying instrument method of measuring phase shifts by comparing the incoming wavelength with the phase of the outgoing light pulse.Laser Security System For HomeSolid objects will reflect back a certain percentage of the emitted light energy. It only needs to be a small percentage for our sensitive detector to pick it. We can measure the time it takes for a laser pulse to travel to the target and back with a reflection. By knowing the constant speed of light we can calculate the distance traveled.Laser based security systemTo get increased accuracy our laser process as many as sixty pulses in a single measurement period. Target acquisition times range will be half second. Sophisticated accuracy validation algorithms are in place to ensure a reliable reading.LTI lasers are completely eye safe and meets FDA Class 1. The radiated light power of our lasers is on the order of 50 micro watts. i.e. approximately one twentieth the light power of a typicalTV remote control.The Laser security systems are high tech innovations that have gained popularity in home and office security systems. These are used to be expensive solutions for security needs. Depending on cost and fast technological advancements laser security systems becoming more adoptable. The features and specifications of the laser security system can be had in detail from the security system dealers who provide high end solutions based on requirement.Advantages of a Laser Security SystemThese are easy to install and work at both within as well as outside houses. These are very effective perimeter alarm systems around properties. In indoor systems can utilize the normal power outlets and jacks making them inconspicuous. At outside these can be easily be hidden behind the bushes or plants without causing any damage. They Consume less power when compared to the laser system as the whole, which is expensive.These laser systems can be installed in homes either by self or by hiring a technical person. Bytechnological innovationscost of the security systems has been cut to a large extent.