SM32 Alarm System Door Sensor:
SM32 Alarm System Door Sensor –
- This door sensor is ideal installation on doors and even window areas.
- Ideal for use on garage doors as well
- The sensor will report when battery needs to be replaced Uses 3V CR123A Battery
Entrances and exits are your home’s weakest points.
And to a burglar, an unsecured door or window is like a big “WELCOME” sign.
To begin with that’s why door sensors—also known as “entry sensors,” “window sensors,” or “contact sensors”
These are some of the most popular home security devices.
The earliest electronic home security system was entirely made up of door sensors,
when someone opened a door or window.
It also triggered a big vibrating bell in a central part of the home.
Luckily, technology has improved since then, and homeowners are faced with a wide array of choices.
Here’s everything you need to know about today’s door sensors:
How they work, how to use them, and how to design the best setup for your home.
HOW DOES A DOOR SENSOR WORK?
Almost all door and window sensors use a “reed switch” to determine when a protected area has been breached.
Reed switches were invented in Bell Telephone Laboratories in 1936, and are used in everything from pedal keyboards to laptops
A reed switch consists of a set of electrical connectors placed slightly apart.
When a magnetic field is placed parallel to the electrical connectors, it pulls them together, closing the circuit.
Door sensors have one reed switch and one magnet, creating a closed circuit.
If someone opens an armed door or window, the magnet is pulled away from the switch, which breaks the circuit and triggers an event.
Depending on your setup and what mode your system is in, this could be a discreet text, a chime alert, or a full-blown alarm.