How to connect an outdoor light sensor to turn on the light

Automation of street lighting control reduces energy costs, simplifies the maintenance of the adjacent territory. The light sensor gives a signal to turn on and off lamps, lanterns, spotlights. An electronic device is bought taking into account the technical parameters of the load. Craftsmen make the device on their own.

Advantages and disadvantages of the light sensor

The light sensor is called a light switch or twilight switch. It monitors the brightness of the lighting on the street or indoors, turns on and off the lamps if necessary. Using an outdoor light sensor has several advantages:

• automation of switching on street lighting;
• accuracy of operation, which allows to reduce the operating time of lighting fixtures and the cost of electricity;
• programmable devices are set according to individual settings;
• scaring off thieves - the system works by simulating the presence of the owners of the house.

Disadvantages:

• low security class of the device provokes rapid oxidation of contacts and breakdown;
• for correct operation, the case periodically requires cleaning.

In places where constant lighting is not required, the twilight switch is supplemented with a motion sensor. The lamps light up only when a person approaches. The system improves energy savings.

The device and principle of operation of the photo relay

Light sensors for turning on street light work without human intervention. They are used on house plots of cottages, highways, construction sites. The photo relay is controlled by a photosensitive photocell. This device recognizes the degree of natural or artificial light and sends signals to the electronic unit.

In the dark, the intensity of the light flux decreases, the parameters of the photo relay change, it closes the contacts. The current flows to the luminaire. In the morning, the contacts open, the backlight turns off.

Components of the device:

• photocell - a photoresistor or phototransistor that changes its own electrical conductivity depending on the brightness of the luminous flux;
• control board - amplifier, electromechanical relay;
• body - the location of all elements, performs a protective and fastening function.

Twilight switches are powered from the mains. Their terminals are switched with a phase of the neutral wire.

Varieties of light sensors

Sensors are classified according to several parameters.

By design, the models are:

• The photocell is located in the same housing with the rest of the parts. The twilight relay is installed next to the lighting device.
• A device with an external (external) photocell. The main unit is mounted on a DIN rail, outdoor light sensor.

By type of control:

• Devices with a timer - the device is adjusted to the level of illumination and the time period of operation is set. For example, lamps turn off at nightfall.
• Photo relays with forced shutdown - if necessary, they are activated and deactivated manually.
• Programmable twilight relays are technologically sophisticated devices that operate according to specified settings.

By load type:

• LED;
• luminescent (energy saving);
• incandescent lamps.

Multifunctional equipment with a timer and motion sensor is more expensive, but it controls lighting more effectively.

Device Specifications

The scope of use of electronic devices is determined by their technical characteristics:

1. Operating voltage - connection of the light sensor is possible to a standard 220 V network or to a 12 V constant voltage source.
2. Degree of protection - outdoor device needs moisture and dust insulation. The protection class is indicated by the IP marking. It must be at least IP44.
3. Maximum current - the parameter shows the permissible current.
4. Operation mode settings - select the sensitivity of the sensor, the delay time for its activation and deactivation.
5. Temperature range - the manufacturer indicates at what temperature the photo relay can be used. Usually it is quite wide, but it is worth clarifying the limit of negative indicators.
6. Dimensions - the dimensions of the device are taken into account when choosing a location.

Experts advise choosing a twilight relay with a load power reserve of 20%.

Review of popular models and selection criteria

Among street lighting sensors, Russian and Chinese manufacturers are in demand. Popular models:

• Photorelay FR-601 from IEK (China) is a device with a built-in photocell. Plastic housing, degree of protection IP44. Works with a voltage of 220 V, a maximum current of 10 A, a load of 2.2 kW. Response threshold 5-50 Lx. Working temperature -25 + 45 °.
• Photo relay FR-7N (Russia) - the equipment has a remote sensor and a 1.5 m cable. Mounted on a DIN rail. Rated voltage 220 V, current 5 A. Illumination range 10-50 Lx, response time 15 s.
• Twilight relay Zamel WZM-01 / S1 (Poland) - the device is mounted on a DIN rail. It is designed for a voltage of 230 V, a load of 4 kW, a current of 16 A. The enclosure protection class is IP20.
• PS-3 EKF (Russia) - the product is designed for a rated voltage of 240 V, a current of 20 A, a load of 4.4 kW. Twilight threshold 5-50 Lx. Protection degree IP44.

To choose a light sensor, study the technical parameters of the device. You will also need to calculate the load power and determine the installation location. These factors influence the type of twilight switch. The main selection criteria include:

• technical specifications;
• the ability to make individual settings for the response limit;
• availability of additional sensors;
• location of the photo relay.

Price is one of the deciding factors when buying. Additional functions increase the cost of the device. If some of the accessories are not required, do not take an expensive model.

Common sensor wiring diagrams

The photo relay connection diagram depends on the number of terminals. Switching takes place in the junction box. Device wires differ in color:

• brown or black - connects to the phase, provides power supply;
• blue - goes to the zero terminal, the lamp wire is directly connected to it;
• red - the output wire feeds the phase to the lighting fixture.

If a motion sensor is included in the circuit, it is connected in series, behind the twilight relay. A switch that controls several luminaires is commutated with a starter. For self-connecting the device, the manufacturer provides a diagram in the instructions.

Installation and connection of photo relay for street lighting

The installation method depends on the selected type of device. The easiest way is to install a wall-mounted photo relay with a built-in photocell. The upcoming scope of work is divided into 3 stages: location selection, installation and configuration.

Seat selection

In order for the twilight relay to turn on and off the lighting in time, it is important to choose the right place for its installation. Accommodation recommendations:

• The device must be exposed to direct sunlight.
• Exclude vehicle headlights to avoid false alarms.
• The device must be freely accessible for service.

If the twilight switch is installed on a DIN rail, only the space for the remote sensor is selected.

Installation work

To connect the photo relay, you can use the junction box of the luminaire. She has already been supplied with food. A separate junction box is installed if necessary. The edges of the colored wires are stripped of insulation. They are connected to the terminals according to the manufacturer's diagram.

Outdoor models include a bracket. The device is fixed in place with screws.

Setting up the device

After connecting the light sensor, adjust its sensitivity. For this, in the lower part of the body there are regulators - discs or toggle switches. According to the marked "+" and "-", it is selected in which direction to rotate the wheel. Adjustment elements set the light threshold at which the twilight switch is activated. On some models, you can select the turn-on delay time.

Is it possible to make a photo relay with your own hands

Making a sensor with your own hands will not be difficult for radio amateurs. For an electronic device you will need:

• triac with built-in dinistro (quadrak) with operating parameters of 4 A and 600 V;
• photoresistor type FSK-7, FSK-G1;
• resistor with a resistance of 47 kOhm.

The circuit is powered from a standard 220 V network. Switching on is configured by a resistor. Its resistance depends on the desired threshold for turning on the backlight. When using a square, you can connect a load of up to 500 watts. This circuit consists of a small number of parts and does not require a separate power supply unit. The elements are fixed on the printed circuit board with a soldering iron.

The cost of twilight switches is affordable for most buyers. Models with a common body are offered at a price of about 400 rubles. Devices that require mounting on a DIN rail will cost more - 1500-2500 rubles. You can install the photo relay according to the manufacturer's instructions.