Some countries have made it mandatory that any garage built after 1991 has to be fitted with safety sensors so that people are not caught under the door. Garage owners have great safety benefits from these door sensors. Infrared beam sensors are the most popular type.
To help out garage owners, there are online dealers such as HomeAlarmSecurity.org dealing with different equipment pertaining to garage doors and they offer the facility of purchasing these equipment online.
They are attached by fastening two pieces of sensors to either side of the garage door so that the infrared light between them is broken by someone walking in front of it. These sensors can become misaligned over time so the owner will need to correct them occasionally.
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The pressure sensor is another type of sensor that is available on the market. This sensor requires professional installation. The first sensor does not allow the door to touch any object underneath it. However, the pressure sensor senses when the door touches an object beneath it. This sensor is less reliable and may not work properly after years of use.
Some door sensors do not address safety concerns but instead focus on the needs of garage owners. Some sensors, which are attached to the garage's entrance and powered by batteries, can automatically close the garage door if it is left open for too long. This is essential for garage owners who live in cold regions. If the garage owner leaves it open for too long during winter, the motorized opener may freeze and stop working properly.