It is impossible to provide the required level of protection for a home, apartment or office space with a reliable lock and a metal door alone. To be sure that intruders will not enter the house without your invitation, we suggest installing a door opening sensor, which will warn about unexpected guests with a corresponding signal on the security alarm control panel. Not all doors have mortise locks - apartments also have windows, balconies, and in houses there is a “back” entrance, in offices there is an emergency exit, so it is impossible to keep all entrances under control, but an element of the smart home system will become a reliable assistant and ensure a comfortable level residence or work.
The need for door sensors in the house
A door sensor helps keep entry and exit areas under control. Being one of the elements of the security alarm system, the device clearly gives signals about what is happening within the operating area. After introducing an electronic device into the system, other modules send a notification to the owner by email, SMS message, or the siren turns on.
At the request of the owner, it is possible to make settings for the devices, which, after receiving a signal, automatically send an alarm call to the specified telephone number to a trusted person. Thanks to the correct configuration, a compact relay can automatically close locks, turn on lights or make lamps blink, or completely de-energize devices.
Principle of operation
An electronic device that responds to opening window sashes, lifting a hatch or housing cover, or opening doors is used as an automation element in Smart Home systems. The reed switch sensor is installed in the required position on the door jamb, window frame, and the magnet is installed on the sash, which is set in motion when opened.
- When it begins to be withdrawn or opened, the external electromagnetic field becomes weaker or the sensor generally leaves the range of the magnet signal.
- At this moment, the elastic property of the contacts is restored - they open, disconnecting the electrical circuit.
This is what the local action of the sensor looks like. Next, the received signal is converted by special devices into light, sound and other alerts. In the closed position of the doors, elastic contacts interact with the field that is created by the magnet - the second part of the module. Being in an insulated glass flask in the zone of action of a magnetic field, the contacts, overcoming elasticity, attract and “stick together”. Thus, the electrical circuit is closed.
Sensor device
A simple mechanism consists of a magnetic component and a sensor - devices with open contacts. If they fall within the range of the magnetic field, the contacts close. An electromechanical switching device - a reed switch - changes the state of the connected electrical circuit due to the presence of a magnet or solenoid nearby.
A reed switch together with an electromagnet is called a reed switch field.
The reed switch has ferromagnetic elastic contacts that are located inside a sealed glass bulb. They function simultaneously as a spring, a current conductor and a magnetic conductor. Their position opens and closes the circuit.
Sound alarm
The sound sensor is installed as one of the elements of the security alarm system. For its uninterrupted operation, electronic modules are required that will convert the signal into some action:
- send a notification to the main server;
- sound a beep;
- turn off or turn on the light.
The sound alarm is used when there is smoke, moving objects, dust in the air, when the device responds to the opening of the door. The sensor is an integral element of the fire alarm, security, control and emergency warning system.
Reed switch for safety
Property protection is the legal right of every owner . A door position sensor will help you cope with the task of monitoring any entrance and exit in a protected area. The magnetically controlled part is installed on a fixed structure, and the response magnet is installed on a movable element of the input group.
Advantages and disadvantages of reed sensors
To make an informed choice of sensor, carefully read the operating and installation features of the device. A wired door sensor has the following advantages:
- simplicity of design, compactness;
- tightness of ferromagnetic alloy contacts;
- absence of friction surface;
- quick response to changes in the magnetic field;
- versatility of the installed relay.
Among the disadvantages of the electromagnetic device are the following:
- low sensitivity of magnets;
- the seal of the glass flask is destroyed when dropped;
- When a low-frequency signal is applied, the contacts open the circuit.
When installing, take into account the specified restrictions specified in the accompanying documentation so that the door opening sensor functions fully and clearly sends a signal.
What are they used for in the home?
Installation of sensors occurs when it is necessary to organize care for elderly people with memory impairment. In this situation, electronic modules help control the intake of medications, food and other important moments in a person’s life. To do this, the devices are installed:
- on entrance and interior doors to receive a signal about the movements of an elderly relative;
- on the medicine cabinet;
- on the refrigerator.
It is important to ensure the safety of children in a large home. To do this, sensors are installed in the following places:
- on the door of the children's room to hear when the child leaves the room at night;
- on a cabinet with items prohibited for children, alcohol, chemicals;
- on the front door to make sure the door lock sensor is triggered, the children are home and safe, or to find out when they left.
But the most important function is protection from the entry of strangers. After all, the reed switch door opening sensor will respond immediately to unauthorized doors. At this moment, the system will give an alarm in the form of sound or light. If the premises have a remote control system, the signal will immediately go to the control room and the security guard will immediately respond to the appearance of an intruder on the premises.
Types of sound alarms for the front door and additional features
The sound alarm, which is installed on the door, becomes a kind of “scarer” for intruders. After the siren turns on, it is difficult to calmly inspect the room and choose the most valuable. A loud, unpleasant sound will most likely cause a thief to run away.
Types of sound alarms
Based on the method of signal processing, a distinction is made between stand-alone and remote alarm systems. The autonomous system notifies the owner of the premises, the control room sends a signal to the security organization with which the contract is concluded. The second option is convenient when the owners do not have the ability to quickly respond to an alarm. If danger arises, security company employees will arrive at the site.
Disadvantages of remote security: availability of a subscription fee, penalties in case of regular violation of the terms of the contract (for example, if the owners of the premises forget to turn on the alarm).
The amount of the subscription fee for remote security depends on the number of security zones (if sensors are installed in other places besides the door) and the floor on which the apartment is located.
Depending on the complexity of the device, set of functions and control method, autonomous sound alarms are divided into four types:
- a simple bell alarm responds to the opening of a door or window: one part of the sensor is attached to the moving part of the door, the other to the stationary part. When they are disconnected, the siren turns on. The cost of such devices is about 400 rubles. You can install them on all doors and windows in the room;
- compact door alarm with vibration sensor for the front door: e
- then the device is installed directly under the door. When it is opened, a siren sound is heard. The device is convenient to use for protecting an apartment, office, or hotel room. You can take it with you on a trip;
- alarm with a built-in motion sensor: its power is provided by AA elements or from the mains. The sensor is installed next to the door. Before leaving the premises, the alarm is turned on by pressing a button on the key fob. The green LED on the remote control lights up. It burns for 20 seconds, during which time you need to get out the door. After this, the object was taken under protection. If there is movement in the room, the red LED lights up and the siren turns on. Remote control range (key fob) - up to 100 m;
- alarm system with GSM standard support: the control panel is equipped with a display with a keyboard. The kit includes wireless door and motion sensors, a siren, a power supply, two control key fobs and an antenna, and sometimes a video camera. To control, a SIM card with entered mobile phone numbers is inserted into the remote control, to which the device sends SMS messages and calls in case of emergency.
Regardless of the type of device, the siren does not turn on immediately after opening the door, but after a few seconds, giving the owners the opportunity to quickly turn it off. The warranty period for most sound alarm models is 1 year.
Up to 99 additional wired or wireless sensors can be connected to an alarm system that supports the GSM standard
Conventional motion sensors are not suitable for protecting premises where animals are constantly present - they will provoke false alarms. It is especially important to remember this when installing a remote control alarm system. There are special sensors on sale with protection against pets.
Additional features of GSM standard sound alarm
Up to 99 additional wired or wireless sensors can be connected to an alarm system that supports the GSM standard: smoke; gas; broken glass; temperature; water leaks; vibrations. They are purchased together with the standard kit. Thanks to these sensors, the alarm system reliably protects the house from intruders and promptly reports a fire, an open tap or a gas burner.
The most modern modifications of GSM standard devices are compatible with Android and IOS systems, which allows you to control them using various applications installed on mobile devices. Some new models also use Wi-Fi to notify of danger. If the network is lost, a message about this is sent to the owner’s phone.
A lithium battery is installed inside the device control unit, which keeps the object protected when the external power is turned off. Voice guidance in Russian helps you set up the device. Some modifications have a room listening function.
Another useful addition is protection by encoding the signal of sensors and key fobs, due to which an attacker will not be able to duplicate the signal and disable the protection. Programming capabilities: arming and disarming an object according to a schedule, remote shutdown and activation of individual zones.
Wireless door sensor
The wireless door sensor has a range of up to 100 m in open space. The transmission frequency at which the device operates is 433 MHz. The operating temperature range from -10 0 C to +50 0 C allows the device to be installed on entrance doors. The new generation of systems allows you to combine and create your own security alarm circuit configuration. The absence of wire connections simplifies the installation and operation of all modular units.
Installing a door opening/closing sensor Door/window Sensor
Door alarm gsm
The wireless door opening sensor consists of a GSM alarm unit with a slot for a SIM card, a mating part of the device, a USB cable for connecting to the power adapter, and adhesive tape for mounting the alarm. When properly assembled, the system represents a reliable security complex. You can connect remote controls and detectors to the wireless GSM alarm kit. Performance specifications require 12V operating voltage.
Operating principle of sensors
The wireless device detects changes in the door position thanks to a response threshold of up to 10 mm. The compact device consists of two elements: a magnet and an operating relay. A reed switch with magnetic field-sensitive contacts is built into the device body.
- When the doors open, contacts using a special protocol initiate the launch of a chain of sequential actions, which lead to a signal being sent to the security alarm control panel.
- The sound module with siren is mounted on the frame, and the magnet is mounted on the front door. A light indicator on the GSM unit will warn the owner that it is time to replace the batteries to ensure uninterrupted operation.
Wireless alarms are installed in places where there is no electricity or a landline telephone network, so some models are designed with a siren. Sensors can be programmed for different areas where control is required - garages, houses, apartments, warehouses, cafes and shops.
Car door open signal
Content
Not long ago I took a ride in a taxi and noticed that when I opened the door, I could hear the melodic sound of a bell. I liked it and also wanted one for myself. There are several similar projects on our forum, for example from AterLux
Buzzer “Bell”, foreign car style, but I think mine won’t be superfluous. The circuit is very simple, assembly is not difficult.
I didn’t start flashing because I initially planned to place the circuit in the doorbell housing. I designed the board according to the available components.
I made the board using photoresist. I found the speaker from my old receiver.
Using resistor R1 we achieve optimal sound, and you can install it on the car. The sound is a soft-sounding bell and there are no audible clicks when turned off. Download the archive with materials for self-production
The archive also contains firmware of Stirmovik's work for 3 minutes from this article.
Thanks to AterLux
for the consultation.
True, I haven’t installed it yet. Maybe I'll get together on the weekend.
Comments 53
I have this Kolokolnikov in my refrigerator, he hit me hard. How could this effect not happen to you?)))
All this is cool, of course, but I would just take an MP3 player from Aliexpress for 100 rubles, and record any sound I liked from the Internet onto it.
Of course you can buy it. Then you should go to the forum that I found on Aliexpress.
My point is that any craft, first of all, should be considered from the point of view of its expediency. Foolishly, you yourself know what can be broken.
Everyone has their own expediency) isn’t it...
This is the theme I made for myself: an independent modification, alarm bells to replace sounds (Musical siren).
If you wish, you can voice anything).
I already ordered the necessary microcircuit on Aliexpress
This is the theme I made for myself: an independent modification, alarm bells to replace sounds (Musical siren). If you wish, you can voice anything).
Tires will puncture 100%
Paradox) whoever has it turns it off)
It’s always like this, they do it and then turn it off.
Things are also like this with minor alterations. Added amplifier LM386. And I installed a buzzer from Omega in the original relay.
The 386 is not the best amp for this application.
Otakoe! But intercoms have been installed for decades and the amplifier works. For speakers 0.5-1 watt will do.
Well, intercoms don’t suck at auto-application. Car crafts must have a low consumption mode.
The circuit only works when the headlights are on and the door is open. There is no consumption in other options.
This is true. And if it is powered correctly, if the seat belt is not fastened and if the speed is exceeded?
