There are many different types of sensor lights on the market. According to the induction principle, they can be roughly divided into four types of sensor switches: light sensor switch, voice control switch, human sensor switch, and microwave switch. These four switches can be used alone or combined with each other to become a multifunctional sensor light, such as our very common sound and light control sensor lights, light control infrared sensor lights, light control microwave sensor lights and so on.

1. Optical switch

Light-sensitive switches are often used in places that require automatic lighting at night, such as courtyard front lights, street lights on city roads, etc. It mainly passes through a photoresistor (its resistance value can be changed according to the light intensity); when the light irradiated on the photoresistor is strong, its resistance value will become lower, and the back-end circuit does not work, and the lamp will not Bright; when the light irradiated on the photoresistor is weak, its resistance value will become higher, and the back-end circuit will work to make the light on. Its shortcoming is that when it is in a dark environment, the switch will continue to be turned on, and the light will always be on, which cannot achieve precise control, and the energy-saving effect is not ideal; it is easily affected by dust or obstacles.

2. Voice control switch

Voice-activated switch is also an earlier automatic control method, usually used in corridors, aisles, corridors and other places, it effectively avoids the influence of dust and obstacles on its use. Its working principle is also very simple. The sound signal is collected through the microphone (commonly known as the microphone), and then processed by the back-end circuit to control the switch on and off to realize the on and off of the light. Usually we will also add a delay circuit on the basis of the voice-activated switch, so that the sound will sound, the light will be on, and after a short period of time, the light will automatically turn off.

3. Human touch switch

The human touch switch is a further improvement on the basis of voice control, which can realize the action of turning on the light without making a sound. It is mainly composed of a pyroelectric sensor plus a Fresnel lens and a peripheral control circuit. Its working principle is that the pyroelectric sensor can sense the thermal radiation released by the body temperature, and the Fresnel lens can collect and focus the infrared rays released by the human body. When someone appears within the sensing range, the Fresnel lens focuses the infrared radiation released by the body heat onto the pyroelectric sensor, and then the pyroelectric sensor outputs a control model to the back-end circuit to realize the on-off control of the light .