Posts Tagged ‘ pir sensor ’

Motion Activated Recording

Thursday, February 10th, 2011

Conservation is the key term in reference to motion activated recording. In the following article, we’ll take a look at how digital video security and surveillance systems go about doing this and why conservation is a key term associated with this type of monitoring.

Digital video camera security systems can initiate motion activated recording in different ways. One of the most common ways to provide motion activated recording is to use a digital video camera with a built-in motion detector. Digital video security cameras equipped with motion detectors begin recording video when motion is detected and stop when motion is either no longer detected or after a designated (pre-programmed) time period.

The motion detector itself is called a PIR or Passive InfraRed sensor. This sensor constantly monitors the passive infrared signature of the camera’s field of vision. When a significant change in this infrared signature occurs (such as when a person, vehicle, or other object passes by) the PIR interprets this change in the infrared signature as motion.

The PIR sensor on motion activated recording cameras is electronically connected to a relay switch. When the PIR detects motion, the relay is energized to the “On” position which turns on the camera and begins the process of recording. When the infrared signature in the camera’s field of view becomes constant, the sensor interprets this as non-motion and the relay switch is then open, shutting the circuit to the camera off. (Many cameras have an intermediary circuit that is programmed to shut the camera off after a time delay in addition to or after motion is no longer detected.)

One of the biggest benefits of PIR motion activated recording is conservation of digital video security system resources. For example a typical motion activated recording system may have one or more motion activated digital video cameras, a Digital Video Recorder or DVR with a Digital Signal Processor or DSP, and an optional monitor. The DVR usually consists of a hard disk drive, like the one in most personal computers and in miniature systems may consist of SD cards, small Integrated Circuit (IC) chips, or other portable non-volatile media.

Even though technology advancements are yielding larger capacity and more efficient storage devices, regardless of the type of storage on the DVR, the capacity is still finite. Furthermore, the digital video files created by the cameras and stored on the DVRs are extremely large files. To keep file sizes as small as possible without losing significant quality, COmpression/DECompression or CODEC utilities are used. These utilities may be in the form of software or a hard-wired IC chip.

CODECs greatly improve the storage capacity of any given drive, conserving on system memory. This is important because whenever storage capacity is reached, the newest digital video files are re-recorded over older digital video files. If the files are archived before hand the data could be lost. There are several ways of improving efficiency in addition to using a CODEC. A larger capacity storage medium can also increase re-recording loop times, handle multiple camera recordings at once, and provide storage space for software programs and other necessary binary information.

Another way to greatly improve the storage capacity and efficiency of the camera-DVR relationship is to only record what is necessary. PIR motion activated recordings or PIR motion detector cameras do exactly that. By recording video only when motion is detected, a tremendous amount of memory on the storage medium is conserved. For some applications, motion detection would only be detected if there is a breach in security (banks and retail stores after hours for example) and this could mean no need to record for days or even months.

Memory is not the only resource that is conserved by motion activated recording cameras. Many users these days prefer the use of totally wireless cameras. These cameras send their digital video data via radio signals to a corresponding receiver that is connected to the DVR or to a DVR with a built in receiver. However, these cameras still require a power source which indicates the use of some sort of power supply carried by a wire to the camera – unless the camera is battery operated.

Battery operated cameras may use standard one-time use batteries or rechargeable batteries. Regardless of the type of battery, motion activated recording drastically conserves battery power as the PIR sensor demands a very small drain on the camera batteries as does digital video recording.


Home Security Camera Motion Sensitive

Monday, December 27th, 2010

One of the most effective residential digital video security systems is the home security camera motion sensitive. This camera not only conserves recording time and power resources put can effectively act as an alarm unit, only recording when motion is detected.

There are basically two types of home security systems, digital video security camera systems and security alarms (intrusion alarms). The home security camera motion sensitive combines the advantages of both systems into one by only recording video only when motion is detected. Not only does the owner benefit from digital video documentation of a potential criminal perpetrator inside the home, but if the system is connected to the internet, an email alert can be sent immediately to the owner’s smartphone notifying them of the intrusion.

If the home security camera motion sensitive is used outdoors, (i.e. is an outdoor type digital video security camera) it can also be used to notify the owner of the presence of someone on or approaching the residential property. Cameras of this type are commonly used on extended driveways or gated property/driveways. They can alert the homeowner of a visitor, long before the visitor arrives at a door.

The home security camera motion sensitive is a digital video camera with a built-in Passive InfraRed (PIR) sensor. The PIR scans the camera’s field of view for a differential in heat signatures, such as that caused by a person walking into the PIR and camera’s field of view. When the PIR detects the change in infrared radiation, it interprets this to indicate motion.

The PIR is connected to a relay inside the camera housing. When the PIR senses motion, it triggers the relay to turn the camera on and begin recording. The camera stops recording either when the PIR no longer detects motion or after a pre-programmed time delay. When the camera is battery operated, the PIR conserves battery life (or time between recharge cycles if the batteries or rechargeable) since the electrical drain caused by the PIR function is drastically lower than that needed for the camera to capture video.

There is also another type of home security camera motion sensitive system. The camera for this system is also on and capturing video images. However, the Digital Video Recorder (DVR) and Digital Signal Processor (DSP) are programmed to recognize changes in the video image of the camera’s field of vision. When this occurs, the DVR begins recording as long as the motion is detected. However, this system uses a non-motion sensitive camera and does not offer the advantage of power conservation as does the home security camera motion sensitive.

Residential digital video security systems are incredibly versatile in application these days thanks to improvements in camera, electronics, and computer technology. There are many additional optional features available for home security camera motion sensitive. The following is a list of some of the more common optional features available:
• Day/night vision cameras. These cameras are very sensitive to light such that they can still produce high quality color video in very low light conditions.
• Night vision infrared cameras. These cameras use infrared illumination which is invisible to the human eye to produce high-quality black and white or monochromatic video in total darkness.
• Outdoor cameras. These cameras are designed with a protective enclosure for the purpose of preventing damage to the camera from exposure to weather and other elements (dust for example).
• Wireless cameras. These cameras send their video transmission data using radio waves instead of cables. Using these cameras eliminates the need for an RG-59 coaxial cable to be run from each camera to the DVR. There are also battery operated cameras of this type creating a truly “wireless” camera.
• Internet Protocol (IP) ready cameras. These cameras contain built-in web server technology and can use the internet as a vehicle for networking. Furthermore, these cameras can be monitored anywhere in the world where broadband internet access is available (including 3G and 4G smartphones).
• Hidden or disguised cameras. Camera technology can produce such small digital video cameras that they can be hidden or disguised as another object.

The various features in addition to the motion detector makes the home security camera motion sensitive one of the most effective residential digital video security cameras. If you need more information on this type of camera or are considering a purchase, contact one of Security Camera King’s security experts via “Live Chat” or telephone today.