m. Сміла, Незалежності, 67г. оф, 406/6
As of september 2026 year, the cheapest opening sensors in our store are:
| Product | Price |
|---|---|
| Ajax DoorProtect contact sensor | 1 329.00 ₴ |
| Contact sensor Ajax DoorProtect Plus | 1 949.00 ₴ |
Brand
Prices
Opening sensors: the alarm is already at the doorstep
The vast majority of break-ins start the same way - someone opens a door or window. The opening sensor reacts to this first action, when the intruder has not even had time to go inside. This is one of the simplest in structure, but surprisingly effective alarm elements, which closes the most obvious ways into the room. This section contains wireless magnetic contact detectors that monitor doors, windows, gates, hatches and other movable shutters on the object.
A principle that is reliable through simplicity
A classic opening sensor consists of two parts: the main unit with a reed switch and a small magnet. The first is installed on a fixed frame, the second on a moving leaf. While the door is closed, the magnet keeps the reed switch closed, and the system “understands” that everything is calm. As soon as the leaf is opened, the magnetic field disappears, the contact opens and the alarm goes to the control panel. There is practically nothing to break here, so such detectors work for years without complaints.
Not just the fact of opening
Advanced models can do more than just detect openings. The built-in accelerometer responds to shocks, vibrations, and tilt of the case, so the system raises an alarm even when a door or window is trying to be swung open instead of being opened in the usual way. Some detectors have an additional wired input to which an external reed switch or other contact is connected - this allows one device to control, for example, a heavy garage door or a separate window nearby.
Where should they be placed?
Entrance doors, balcony blocks, lower floor windows, attic hatches, wickets, safe doors or cabinets with important documents - all these are natural places for a magnetic contact sensor. The compact housing is almost invisible and does not spoil the appearance of the door, and different colors help to choose a shade for the interior. Since the power supply is autonomous, from a battery with a long service life, installation does not require either gating or wires - often high-quality double-sided tape or a few screws are enough.
A small device with a big role
Against the backdrop of cameras and powerful control panels, the opening sensor looks like a trifle, but it is often the one that stops theft in the very first seconds. Communication with the control panel is via a protected radio channel, the device status and battery charge are visible in the application, and the system perceives an attempt to tear the housing off the wall as an alarm signal. In combination with motion sensors and sirens, opening control becomes the first link in a well-thought-out protection that works even before the intruder gets inside.
How many are needed?
The guideline is simple: all doors and windows that can actually be penetrated should be monitored, primarily at ground level and in areas hidden from prying eyes. A few sensors are usually enough for an apartment, while a private house needs more. If you are not sure which openings to close first, comfortlife.market consultants will suggest the logic of the arrangement so that no vulnerable spot is overlooked.
