Sensors, as devices for signal acquisition and electromechanical conversion, have matured in their electromechanical technology. In recent years, sensor technology has made great strides towards miniaturization, intelligence, multifunctional, and low-cost. Various types of sensors such as photosensitive sensors and infrared sensors can be combined with LED lighting fixtures to form an intelligent control system. The sensors convert the collected physical signals into electrical signals, which can be intelligently processed through integrated circuit AD (analog-to-digital) converters, MCU (micro controller), and DA (digital to analog) converters to control the opening and closing of LED lighting fixtures. And through this, various control requests can be set on the MCU to control the switching time, brightness, color display, and colorful changes of LED lights, thereby achieving the goal of intelligent lighting control.

Photosensitive sensor

A photosensitive sensor is an ideal electronic sensor that can control the automatic switching of circuits due to changes in illumination during bright and dark days (sunrise, sunset). The photosensitive sensor can automatically control the opening and closing of LED lighting fixtures based on weather, time period, and region. In bright daylight, by reducing its output power to reduce power consumption, compared to using fluorescent lamps, a convenience store with an area of 200 square meters can reduce power consumption by up to 53% and have a lifespan of about 50000 to 100000 hours. Under normal conditions, the lifespan of LED lighting fixtures is about 40000 hours; The color of the light can also be changed in RGB (red green blue) color, making the lighting more colorful and the atmosphere more lively.

A photosensitive sensor is an ideal electronic sensor that can control the automatic switching of circuits due to changes in illumination during bright and dark days (sunrise, sunset). The photosensitive sensor can automatically control the opening and closing of LED lighting fixtures based on weather, time period, and region. In bright daylight, by reducing its output power to reduce power consumption, compared to using fluorescent lamps, a convenience store with an area of 200 square meters can reduce power consumption by up to 53% and have a lifespan of about 50000 to 100000 hours. Under normal conditions, the lifespan of LED lighting fixtures is about 40000 hours; The color of the light can also be changed in RGB (red green blue) color, making the lighting more colorful and the atmosphere more lively.

infrared sensor

Infrared sensors work by detecting the infrared radiation emitted by the human body. The main principle is that the human body emits 10 μ The infrared ray of about m is strengthened by the Fresnel filter lens and converged on the pyroelectric element PIR (passive infrared) detector. When people move, the emission position of infrared radiation will change, and the element will lose charge balance. The pyroelectric effect will release charges outward, and the infrared sensor will convert the changes of infrared radiation energy through the Fresnel filter lens into electrical signals, that is, thermoelectric conversion. When no human body moves in the detection area of the passive infrared detector, the infrared sensor only senses the background temperature. When the human body enters the detection area, passing through the Fresnel lens, the pyroelectric infrared sensor senses the difference between the Human body temperature and the background temperature. After the signal is collected, it stops comparing with the existing detection data in the system to determine whether there is really someone or other infrared sources entering the detection area.

Passive infrared sensors have three key components: a Fresnel filter lens, a pyroelectric infrared sensor, and a matched low noise amplifier. The Fresnel lens has two functions: first, focusing, which refracts the thermal infrared signal onto the PIR; second, dividing the detection area into several bright and dark areas, allowing moving objects/people entering the detection area to generate thermal infrared signals on the PIR through temperature changes. Normally, it will also be matched with a low noise amplifier. When the ambient temperature on the detector rises, especially close to the normal body temperature (37 ℃), the flexibility of the sensor decreases, and through it, the gain is compensated to increase its flexibility. The output signal can be used to drive electronic switches and complete the switch control of LED lighting circuits.

ultrasonic sensor

Ultrasonic sensors, similar to infrared sensors, have gained more applications in automatic detection of moving objects in recent years. The ultrasonic sensor mainly uses the Doppler principle to emit high-frequency ultrasound beyond human perception through the crystal oscillator. Generally, 25~40kHz waves are typically selected, and then the control module detects the frequency of the reflected wave. If there is movement of objects in the area, the reflected wave frequency will have a slight shake, that is, the Doppler effect, to judge the movement of objects in the lighting area, so as to achieve the purpose of controlling the switch.

The longitudinal oscillation characteristics of ultrasound can propagate in gases, liquids, and solids with different propagation speeds; It also exhibits refraction and reflection phenomena, with lower propagation frequency and faster attenuation in air, while in solids and liquids, it has smaller attenuation and travels farther. Ultrasonic sensors precisely apply these characteristics of ultrasound. Ultrasonic sensors have characteristics such as large sensitivity range, blind spots, and no interference from obstacles, and have been proven to be the most effective method for detecting small object movements. Therefore, the system composed of LED lamps can flexibly control the switch. Due to the high flexibility of ultrasonic sensors, air vibration, ventilation, heating and cooling systems, and the movement of adjacent spaces can cause false triggering of ultrasonic sensors. Therefore, ultrasonic sensors need to be calibrated in a timely manner.

temperature sensor

The temperature sensor NTC (Negative temperature coefficient) is widely used earlier as the over temperature maintenance of LED lamps. If high-power LED light sources are used for LED lamps, it is necessary to use multi wing aluminum heat sinks. Due to the small space of LED lamps used for indoor lighting, heat dissipation is still one of the biggest technical bottlenecks.

If the heat dissipation of LED lamps is not satisfactory, it will cause early light decay of LED light sources due to overheating. After the LED lamp is turned on, heat will also accumulate towards the lamp head due to the automatic rise of hot air, affecting the lifespan of the power supply. Therefore, when designing LED lighting fixtures, an NTC can be tightly attached to the aluminum radiator near the LED light source to collect the temperature of the fixture in real time. When the temperature of the aluminum radiator in the lamp cup increases, this circuit can be applied to automatically reduce the output current of the constant current source and cool the fixture; When the temperature of the aluminum radiator in the lamp cup rises to the limit set value, the LED power supply is automatically turned off to complete the maintenance of the lamp over temperature. When the temperature drops, the lamp is automatically turned on again.

Voice sensor

A microphone array composed of a sound control sensor, an audio amplifier, a channel selection circuit, a delay start circuit, and a thyristor control circuit. Using sound comparison results to determine whether the control circuit can be activated, a regulator is used to set the original value of the sound control sensor. The sound control sensor periodically compares the external sound intensity with the original value, and sends a "sound" signal to the control center when it exceeds the original value. The sound control sensor is widely used in corridors and public lighting places.

Microwave induction sensor

Microwave induction sensor is a mobile object detector designed based on Doppler effect principle. It detects the position of an object in a non-contact manner and generates corresponding switch operations. When someone enters the sensing area and reaches the lighting demand, the sensing switch will automatically turn on, and the load appliance will start working and start the delay system. As long as the human body does not separate the sensing area, the load appliance will continue to work. After the human body separates the sensing area, the sensor begins to calculate a delay. After the delay is completed, the sensor switch automatically closes and the load appliance stops working. Truly achieving safety, convenience, intelligence, and energy conservation.