Photo Detector
Detect the intruder!
The PIR sensor is a powerful Photo Detector with an integrated flash that can be used to take pictures even in total darkness. When our motion sensor detects an intruder, it automatically sends a sequence of images to our Alarm Receiving Centre. Our team then analyzes the images captured by the photo sensor and, if necessary, contacts Guard Response.
More About Photo Detectors For Home Security
What is a Photo Detector?
As I have shown you earlier in this newsletter, there are many different types of sensors which can be used to detect the presence of people or animals. A very common type of sensor is called a “passive infra-red” (PIR) sensor.
A PIR sensor works on the same principal as a television remote control. It has an infra-red (IR) beam which is invisible to the human eye. If an object interrupts the IR beam, a circuit in the sensor is completed and an alarm is triggered.
Importance of Photo Detector
Using a photo detector at home or in your office is the most reliable way of detecting unwanted visitors. If you use an alarm system made by a reputable company, there is less than one chance in a thousand that your home or office will be breached by a criminal.
Using a photo-detector at home or in your office increases this security to almost 100%.
The photo detector can be operated from the same remote control as the PIR motion sensor, which will save you time and energy.
What Happens If An Unwanted Visitor Is Detected?
If you are using a standard PIR photo detector with a radio transmitter, the visitor will hear a loud audible alarm. This lets you and your family know that someone is in your home or office and gives you enough time to take whatever action is necessary.
However, if you are using a wireless radio controlled photo detector (as we provide), the visitor will hear a very high pitched beeping sound.
This means he has been detected and is being warned to immediately leave your home or office.
How Does The Photo Detector Works?
PIR photo detectors consist of an infra-red LED (Light Emitting Diode) light source and an infra-red sensitive element called a “polaroid lens”. This small plastic lens is mounted directly in front of the LED so that it has a clear line-of-sight to any objects which are within range of the IR beam.
The LED produces a narrow beam of IR radiation. The polaroid lens focuses the IR radiation into a cone-like pattern which has a large field of view. Anything which comes between the LED and the sensor will cause the sensor to trigger an alarm.
Besides people and animals, PIR sensors can also detect: Furniture – especially beds and sofas Water – in all its forms (lakes, rivers, oceans, etc.) Tools – such as drills, saws and hammers Motor vehicles The beam from the IR LED is very narrow.
That means that only the object which is directly in front of the sensor will cause it to trigger an alarm. All other objects (such as walls, furniture and motor vehicles) will not set off the alarm.
What is an Alarm Receiving Centre?
An “Alarm Receiving Centre” (ARC) is a location which receives the alarm signals from the network of PIR sensors. The ARC determines if the alarm is valid or not.
If it is not valid (i.e. the alarm was caused by a malfunctioning PIR sensor), the ARC sends an “error signal” back to the sensor. In this case, the sensor must be repaired or replaced before it can again be used to trigger an alarm.