| The ever growing demand of more and more means | | | | Passive versions work in a completely different |
| of ensuring precautionary safety measures has | | | | manner. They do not emit any signals at all. The |
| compelled home security companies and designers to | | | | infrared sensor is an example of a passive sensor. It |
| come up with numerous designs. Earlier, security | | | | is meant to monitor the heat signals of objects |
| alarms used to be standalone without any upgrades. | | | | present in the surrounding. Passive infrared sensors |
| The ones that existed were far too expensive and | | | | are often paired with an active microwave sensor in |
| usually were ignored by the end user. | | | | order to prevent false alarms as microwave sensors |
| Not many buyers are aware of the things that should | | | | are accurate and can easily discriminate between a |
| be looked upon before buying a motion sensor alarm. | | | | person and pet. |
| It is always good to do a bit of research and have a | | | | Ultrasonic sensors observe the echoes which are a |
| look at market surveys before buying such a | | | | result of signals bouncing off objects. On the other |
| sensitive product. These use sensors that detect | | | | hand photo sensors operate by transmitting a ray of |
| motion principally and any abrupt change in standard | | | | light onto a sensor. If any object slices the ray the |
| pattern is referred to as motion which triggers the | | | | alarm is triggered. This however is not an efficient |
| alarm, video recorder or lights in some cases. | | | | method to secure your space as you might often |
| Various types of motion sensor alarms exist in the | | | | find false alarms being triggered. |
| market these days. Each one of them is based on a | | | | These alarms are often deployed in crucial areas of a |
| separate principle at the back end. There are two | | | | house or office where important assets are kept. |
| types, active and passive. An active version is a | | | | Some of them are programmed to switch on and off |
| sensor that emits a spectrum and monitors the | | | | at a certain time. Others may be controlled manually |
| reflections from the object. Change in the reflected | | | | depending on the user's choice. The most common |
| signal is termed as motion and triggers the alarm. | | | | form of a sensor alarm is the burglar alarm because it |
| Most of these active sensor alarms normally work in | | | | is mostly used to safeguard private property and |
| the ultrasonic and microwave wavelength band. | | | | businesses. |