Sensitive elements of sensors and detectors are actively included in the daily lives of ordinary citizens, increasing their comfort and safety. With the help of sensors, it is possible to automate electrical engineering and equipment systems, which also expands the functionality of devices. One of the most popular devices of this type is the built-in motion sensor, which is used to control the lighting system.
Design of the device
Externally, the device is a small plastic box that houses sensors of one type or another. Due to the electrical filling and the connection to the control panel, the sensor transmits a signal, after which the lighting device is triggered. In this case, the most common design of a hidden built-in motion sensor is considered. Its features caninclude the possibility of integration into a ceiling niche, a wall or a prepared connector. The main thing is to leave the possibility of free access to the sensitive element. Only wired models do not require constant maintenance, for which only the connection cable is left, but battery-powered devices will periodically have to be dismantled to renew the batteries.
How the motion sensor works
All devices of this kind work according to the general scheme - fixing a certain feature in the coverage area, analyzing the signal and transmitting it to the target equipment (control panel or directly to the lighting device). Another thing is that the very annoying sign can be different. For example, lamps with a built-in motion sensor with infrared sensing elements are widely used today. They are guided by the fixation of infrared radiation from surrounding objects. Ultrasonic models are also attractive in their own way, which capture noise reflection at frequencies from 20 to 60 kHz. This principle of operation is characterized by the accuracy of signal fixation and independence from surrounding negative factors, but if there are animals in the house, then ultrasound should be abandoned immediately.
Not so popular in domestic use, but still retain a certain demand, microwave embedded motion sensors, the design of which can be compared with microwave locators. Models of this type generate microwave radiation, taking reactions to it from the environment. The big advantage of suchsensors is the ability to detect a person on the way to the door, which activates the lighting in advance of the entrance. But this is also the disadvantage of microwave sensitive sensors, since they have one of the highest false alarm rates.
Instrument Placement Requirements
The performance, accuracy of user detection and the same false alarm rate are directly affected by the location of the sensor. When choosing a mounting point, the following parameters are taken into account:
- Installation height. It is important to focus on the height of the people who will use the lamp. If there are children in the house, then the minimum altitude level of the device is determined by their height. This does not mean at all that the device itself should be at a height of about 1-1.5 m. It is precisely the zone of operation of the sensitive element that should extend to the approach of children. But, for example, cats and dogs should not fall into it.
- Radiation propagation range. The average coverage distance of LED lamps with a built-in motion sensor is 5-6 m. This value is usually used to determine the location of the detector relative to the entrance or zone where the user's approach should be recorded.
- Wrap angle. This is the horizontal sector that defines the span width of the workspace where the target object passes. So, if the room has two entrance doors, then the sensor is located between them so that both areas are simultaneously covered.
What else to considerin choosing the installation location?
It will be useful to foresee possible interference from the environment. The slightest obstacle, for example, can reduce the range of the sensor. Most sensors also respond to temperature and light changes. If there is climatic equipment in the room, then it is better to mount the sensor in a protected housing. For example, in this case, it is advisable to use the installation of a motion sensor that is built into a socket box or other insulated housing. If there is electromagnetic radiation, this will increase the risk of false positives. But even if it was possible to eliminate all the existing interference in the room, you should correctly orient the sensors directly to the working area. For example, infrared optics must be positioned so that the lenses point perpendicular to the user's line of motion. These and other nuances are taken into account at the design stage of the lighting system.
Typical device connection
To begin with, you should disassemble the design of the device. This operation is easily performed with a screwdriver by unscrewing the rear panel. Inside there should be a block for connecting wires. Through it, an electrical circuit is organized with a lighting device included in it. In turn, the detector should open or close to the circuit, depending on the current status. In the standard circuit, the block has the following designations: L (phase), N (zero), A - usually a wire with an arrow that should connect the circuit to the targetcontrol device. The connection of today's popular LED recessed luminaires with a motion sensor is made with the expectation of full control from the sensing element, that is, without a switch. The main advantage of this method can be called the elimination of the need for access to the junction box. From the L terminal on the block, a wire is directed directly to the phase. From the native terminal N, the line departs along the contour of the neutral wire to the lamp. From terminal A there is also a wire leading to the lighting fixture.
Connection using switch
From the N-terminal, the wire will be directed to the junction box to the neutral circuit. In the same zone, wiring for the lamp is organized. From line L, the phase is led to the switch and connected to the middle (neutral) terminal. In this position, the lighting is controlled via a sensor. But the task of the switch for the built-in motion sensor is precisely to provide the possibility of redundant manual control. Therefore, another wire departs from the A-terminal, connecting the sensor and the lighting device. A wire will be directed from the lamp to the switch to the terminal associated with the activation of the upper position of the key. This part of the circuit is responsible for controlling the lighting with a switch. The bottom position of the key is to turn off the light.
Sensor mount
After performing electrical measures, you can install the device in a prepared niche, case or connector. In case ofintegrated sensors, mounting kits often contain special boxes for mounting the device in the same sockets. The master is only required to make mounting holes for complete self-tapping screws or dowels, and then embed the case into a previously created niche of the appropriate size. The motion sensor already built into the socket is additionally masked by a cover or mounting plate. It is desirable that a simple mechanism for dismantling the device be provided, which will facilitate its operation.
Device testing
When the connection and installation activities are completed, you can start testing the device. But before that, you need to make basic settings in terms of sensitivity. Testing is performed on several parameters. First, the quality of the response is evaluated in terms of the sharpness of the movement. It is necessary to pass through the coverage area several times at a different pace and determine the optimal sensitivity of the device operation - if the nature of the detection does not match the set settings, it is corrected. Secondly, after switching on, the lamp with a built-in motion sensor must maintain an active state for a certain time (fixed in the settings). Both the delay time and the duration of the active operating state should be noted. The main task of the test is to test the device for compliance with the settings made.
Conclusion
The use of a motion sensor is not just a means of improving the ergonomics of the systemlighting, but also a sure way to save energy. Properly performed installation of the device with a suitable connection diagram will certainly save you from the operational hassle associated with the constant switching of lights and lamps. For this reason, recessed lights with motion sensors are more often used by owners of private houses when organizing outdoor lighting. But for urban residents, the automation of lighting systems is no less relevant for the same reasons of energy saving. Thus, according to experts, the inclusion of motion sensors in the network due to rational management can reduce energy consumption by 30-50%.
