Where Can I Buy Door Contacts for My Alarm System?

You can buy door contacts for your alarm system from the Alarm Grid website. You can find door and window alarm sensors for almost any type of security panel. Both surface-mount and recessed contacts are available. We have hardwired door sensors and wireless door sensors to meet your needs.

A door contact is a sensor that alerts an alarm system when a door is opened. It works using a sensor and a magnet. The sensor is usually mounted on or inside the door frame, while the magnet is usually mounted on or inside the door. When the door is closed, the magnet should be in direct contact with the sensor. This is why door sensors are often referred to as "contact" sensors.

When the magnet is in direct contact with the sensor, a metal reed switch inside the sensor will be kept closed. But opening the door will cause the magnet to separate from the sensor. This will release the metal reed switch and cause it to open. The system will display a fault condition for the associated zone when this happens. Since the system usually expects the reed switch to be closed, door contacts are referred to as Normally Closed (NC) sensors.

Door contacts are simple in functionality. But there are many varieties available. Door contacts can differ in terms of how they communicate with the alarm control panel and how they are positioned with the door. One main way to distinguish between different door contacts is to check whether they are hardwired or wireless.

A hardwired contact will connect directly with the panel or wireless converter through a hardwired connection. All data and information will travel through the connection. The contact will not need a battery or power supply, as the action is purely mechanical. This means that a hardwired contact will require no maintenance once installed. However, the initial installation will require running wires.

A wireless contact sends a wireless communication signal to a compatible panel. The contact will need a battery installed to send out these signals. In most cases, the battery will need to be replaced every three to five years. The wireless contact must communicate at a wireless frequency that is compatible with the wireless receiver used with the panel.

Make sure you choose the correct frequency if you decide to buy wireless contacts. Some popular frequencies used with alarm systems include 319.5 MHz, 345 MHz, 433 MHz and 915 MHz. Other encrypted frequencies may also be used. Many users prefer wireless contacts since they are easier to install. But replacing the battery requires minor maintenance. Also keep in mind that wireless contacts have a limited signal range. You may need a compatible repeater to increase the range.

Door contacts can also be surface-mounted or recessed. Surface-mounted contacts are installed on the outer surface of the door. This makes them visible from the outside. They are easy to install, since no holes need to be drilled. But some users might not like being able to see the sensor on the outside.

Recessed contacts can be a better option for users who want a more aesthetically pleasing installation. These sensors are installed inside the door and its frame. Holes will need to be drilled to install the sensors. This can make initial set up more challenging for a DIY user. But the advantage is that the contacts will not be visible from the outside.