The device emits or detects infrared radiation to sense specific phases in the environment. In general, thermal radiation is emitted by all objects in the infrared spectrum, and infrared sensors detect this radiation that is invisible to the human eye.

　　Working principle

　　The basic idea is to use infrared light-emitting diodes to emit infrared light to objects. Another infrared diode of the same type will be used to detect waves reflected by objects. The working principle of the infrared Led sensor is shown below.

　　When the infrared receiver is irradiated by infrared light, there is a voltage difference on the wire. Since the voltage generated is small and difficult to detect, an operational amplifier (op amp) is used to accurately detect low voltages.

　　Measuring the distance of the object from the receiving sensor: The electrical characteristics of the infrared sensor assembly can be used to measure the distance of the object, and when the infrared receiver is exposed to light, the potential difference will be generated on the wire.

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