infrared sensor notes sensors & transducers
- 1. IR Sensor An infrared (IR) sensor is an electronic device that measures and detects infrared radiation in its surrounding environment. Infrared radiation was discovered by an astronomer named William Herchel in 1800. IR is invisible to the human eye, as its wavelength is longer than that of visible light (though it is still on the same electromagnetic spectrum). An IR sensor can measure the heat of an object as well as detects the motion. Usually, in the infrared spectrum, all the objects radiate some form of thermal radiation. These types of radiations are invisible to our eyes, but infrared sensor can detect these radiations. working principle of an IR sensor IR sensors work by detecting infrared radiation emitted by objects in the environment. They typically use a photodiode or a phototransistor to detect the IR radiation and convert it into an electrical signal that can be processed and analyzed. Types of IR There are two types of infrared sensors: active and passive. Active IR sensors Active IR sensors are commonly used in obstacle detection systems (such as in robots). Active infrared sensors consist of two elements: infrared source and infrared detector. Infrared sources include the LED or infrared laser diode. Infrared detectors include photodiodes or phototransistors. The energy emitted by the infrared source is reflected by an object and falls on the infrared detector Passive infrared (PIR) sensors Passive infrared sensors are basically Infrared detectors. Passive infrared sensors do not use any infrared source and detector. . Passive infrared sensors are comprised of: Two strips of pyroelectric material (a pyroelectric sensor) An infrared filter (that blocks out all other wavelengths of light) A fresnel lens (which collects light from many angles into a single point) A housing unit (to protect the sensor from other environmental variables, such as humidity) IR Sensor Types There are several types of IR sensors, each with different characteristics and applications. Some common types include: 1. Passive Infrared (PIR) Sensor: PIR sensors are used to detect motion by sensing changes in infrared radiation. They are commonly used in security systems, lighting control, and automatic doors.
- 2. 2. Reflective IR Sensor: Reflective IR sensors use infrared LED to emit infrared light and a phototransistor to detect the reflected light from an object. They are used to measure distance and detect proximity. 3. Transmissive IR Sensor: Transmissive IR sensors use infrared LED to emit infrared light and a phototransistor to detect the light that passes through an object. They are used to measure distance and detect proximity. 4. IR proximity Sensor: IR proximity sensors are used to detect the presence of an object without making physical contact. They are commonly used in mobile devices, robotics, and automation systems. 5. IR temperature Sensor: These can measure the temperature of an object by detecting the infrared radiation emitted by it. They are used in industrial, HVAC, and medical applications. 6. IR spectroscopy Sensor: These can use infrared radiation to analyze the properties of a substance. They are used in chemical analysis, medical diagnosis, and environmental monitoring. 7. IR Imaging sensor: These sensors use infrared radiation to create images, they are used in thermal imaging, night vision, and surveillance cameras. Advantages IR sensors have many advantages, including high accuracy, non-contact operation, and immunity to electromagnetic interference. They are also widely available and relatively inexpensive. Applications of IR Sensor IR sensors use in various projects and also in various electronic devices. They all are as follow, Night Vision Devices Radiation Thermometers Infrared Tracking IR Imaging Devices