Can You Put a Motion Sensor on Any Light? How to + Video


When I was recently renovating my house I wondered if I can add a motion sensor to my floodlight. So, I did some research and testing to find out.

So can you put a motion sensor on any light? Yes, of course! Installing a separate motion sensor and connecting it to an existing light source is much cheaper than buying lighting with an already built-in motion sensor.

Motion Sensor and Twilight Sensor. Automatic Lighting Outside the House 

When darkness falls, the light at the entrance to the house and garage should switch on automatically. 

When it gets dark, the entrance to the house and the entrance to the garage need lighting. 

It is best to use one that switches on automatically, i.e., controlled by a motion sensor or a twilight sensor. 

After dark, we do not need to illuminate the whole property, but the light at the entrance door and over the garage entrance is the minimum that we should take care of. 

Light can be switched on manually, but then you have to remember to turn it on in the evening and turn it off in the morning, and in the absence of the household members, the property will sink in the dark.

To improve comfort and safety, it is advisable to equip the outdoor lighting with an automatic control with a twilight sensor or a motion sensor. 

Twilight Sensor 

The easiest way to replace the light source is to replace it with one with a built-in twilight sensor. 

This solution has two disadvantages: the high price and the fact that if the light source burns out, you have to buy a new one, including one with a sensor. 

The second solution, which consists of installing a separate twilight sensor and connecting it to an existing light source, seems more reasonable. It’s also much cheaper. 

In addition to the twilight sensor, we also need to buy three electric blocks to connect the wires and a voltage tester, the so-called test tube. 

Installing the Twilight Sensor 

A typical electrical installation in a single-family house is made of three-core electric cables. 

In each of them, there are three wires: 

  • Brown marked with the letter L (linear, phase)
  • Blue marked with the letter N (neutral)
  • Green or green-yellow, marked with the letters PE (so-called ground).

Before starting the installation of the twilight sensor, we must first turn off the power supply in the electrical circuit that operates the outdoor lighting. 

For this purpose, the overcurrent circuit breaker protecting it, located on the fuse board (switchgear), should be moved to the off position. 

If we do not know which fuse (circuit breaker) is responsible for the circuit with external lighting, we can always switch off the main fuse or – for safety reasons – simply all of them in the fuse board. 

We remove the diffuser so that there is access to the light source and electrical terminals in the exterior luminaire. 

We switch on the fuses for a while and carefully, using a test tube, check that the luminaire is connected correctly. 

The phase wire (brown) should be connected to the L terminal in the luminaire, the blue wire to the N terminal and the green to the PE terminal in the luminaire housing. 

The luminaire switch located on the wall in the hallway should be mounted on the phase wire. 

Every twilight sensor you buy will have an installation diagram attached, explaining how to connect it to the installation. 

The twilight sensor has a short connection cable consisting of three wires: brown, blue, and yellow. 

According to the scheme, we connect the brown wire of the sensor with the brown wire L of the house installation, the blue wire with the blue wire N of the house installation and the N terminal in the luminaire, and the yellow wire with the L terminal in the luminaire. 

We do not connect the wires directly, but with the use of electric cubes. 

The connection cable of the twilight sensor is inserted into the luminaire through the existing hole (if there is no such hole, we have to make one). 

The sensor should be mounted near the luminaire, in such a place that the light from the luminaire does not fall directly on it.

All electrical connections are made with the use of electric cubes inside the luminaire. 

The cables in the luminaire should be laid in such a way that they do not touch the light source and are as far away from it as possible.

When the work is finished, switch on the fuses and the outdoor lighting switch in the hallway. 

The light source should now be in standby but not lit. Only when twilight arrives should it be automatically switched on and off in the morning. 

We can check it right away by covering the twilight sensor with our hands for a moment. 

After checking that everything is working properly, we put on the dome of the luminaire. 

It is necessary to switch off the fuses in case of an emergency beforehand. 

Wiring a Motion Sensor to an LED Light

Twilight Sensor and Motion Sensor 

Lighting switched on at dusk is also very useful at the entrance to the garage. 

The lighting circuit that powers these luminaires can be fitted with a twilight sensor with an additional motion sensor so that the light only comes on when it is dark, and someone else is in front of the garage.

Simple sensors with a twilight sensor and a motion sensor in a single housing are enough for this. 

The selected sensor has two additional knobs – one for adjusting the light intensity at which it will be activated, the other for setting the light intensity. 

The operating time of the selected sensor is between 10 seconds and 7 minutes. 

Mounting the sensor is a good opportunity to replace damaged luminaires with new ones. 

A good solution, in this case, is LED luminaires fixed to the roof.

We start by switching off the lighting circuit with the appropriate fuse. Then we dismantle the old luminaires.

The sensor is attached to the roof soffit, centrally above the garage entrance. 

Both luminaires will be located symmetrically on both sides of the building.

According to the diagram attached to the sensor, both luminaires should be connected to the sensor, and the power cord should be lead to the sensor. 

After all electrical connections are made, switch on the lighting circuit with the appropriate fuse and light – a switch in the garage. 

It is more convenient to carry out work during the day when it is light, but then it is difficult to check whether everything has been done properly because the twilight sensor does not work when it’s bright. 

After checking that everything is working properly, you can (after switching off the fuses again, just in case) finish mounting the luminaires and the sensor. 

It is best to make the final adjustment of the sensor after dark, using the knobs to set the light intensity at which the sensor is to be activated and the time of light. 

From now on, make sure that the light switch is always in the “on” position.

Design a Smart Lighting System With Motion Detectors 

Turn on the light when you need it. Motion detectors are an essential part of an intelligent lighting system.

Their use means not only comfort and convenience but also significant energy savings because sensors switch on the light when it is needed and switch it off when it becomes unnecessary. 

They are perfect for public buildings, especially in traffic routes, as well as private houses and flats: wardrobe, basement or hallway.

Microwave or Infrared? 

Motion detects the presence of a person or other object in their field of vision in a room or area and automatically activates other devices.

They are most often used to control lighting, although they can also initiate an alarm, for example. 

Depending on the way the sensors work, they can be divided into two groups: 

  • Infrared: Sensors register fluctuations in heat radiation and, thanks to the use of a segmented lens, become motion signals –
  • Microwave: Sensors emit radio waves of high frequency, about 1-10GHz, which reflect on objects, animals, people, and return to the detector. The system compares the transmitted wave with the received wave and interprets any change as a movement. 

What Should We Pay Attention to When Choosing a Sensor? 

Everything depends on its purpose and application. If the sensor is to be placed outdoors, its housing must have an IP degree of protection.

The measuring angle is also important. The standard range is about 160˚ – 180˚.

But if you want to place the sensor on the ceiling in the middle of a room, choose a detector with a 360˚ measurement angle. 

It is also worth noting the rated load, usually in watts, which indicates how many bulbs or other devices can be connected to the sensors.

Two or even three adjustable parameters help to better adapt the sensors to our needs. 

The switch-on time is the time since the last detection of movement before the sensor switches off the lighting. 

The light is switched on as soon as motion is detected, but it is up to us to decide how long it is to stay on, depending on the purpose of the sensor. 

A different time of switching on will be programmed at the entrance door and a different time in the corridor or driveway. 

Sensor Mode of Operation 

The method of motion detection used in them determines their purpose. 

The infrared sensor is passive, does not send any signals, so an obstacle in the form of even a thin wall or door will make the sensor not work. 

The detector does not detect our presence either, so when we stop moving, even if we remain in its field of view, and there are no thermal changes, the sensor will switch off the lighting. 

Therefore, this type of sensor is perfect for places where we appear occasionally, and where the light is mainly switched off: in the hallway, driveway, or before entering the house. 

In these places, it is simply uneconomical to keep the lighting on all night long. 

The sensor helps to save energy, especially if we forget to turn off the light, the sensor will do it for us, taking care of our bills. 

This solution will be appreciated not only by night people but also by parents, whose children like to wander around the house at night.

With Microwave Sensors, Thin Doors and Walls are No Obstacle. 

When calibrating the appropriate sensitivity of the device, we can achieve the effect in which the switched on light will greet us in the room before we even open the door to it in the wardrobe, hallway or basement. 

In this situation, the microwave sensor reduces the discomfort of entering a dark room. 

If aesthetic considerations are important to us, it is worth remembering that the microwave sensor can be hidden behind a suspended ceiling or plasterboard cover. 

The motion detector is often part of an alarm system or switches on other electrical devices. 

However, if you use it only to control lighting, you should consider buying a plafond with a built-in motion sensor. 

Such a solution is much easier and simpler, and the sensor built into the plafond has the same functions as those installed separately, including light intensity control and on/off time/latency time. 

The use of motion detectors is one of the simpler solutions, allowing you to adjust the lighting to individual needs and preferences, while at the same time bowing to energy savings. 

The use of sensors to automatically switch on lamps makes the use of lighting more comfortable, convenient, and cheaper to use.

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