Infrared (IR) sensors are used in night vision
How it works:
Red color has the longest wavelength and infrared means the wavelengths below this visible red. The IR detecting unit uses a silicon photodiode as the light-detecting source to convert the infrared radiation into an electric current. Since an object like a human body has different temperature zones, the electric current that is produced will also vary and can be used to form a map of temperatures or varying infrared colors from dark red to blue.
The following factors are useful in selection:
* Responsivity - the responsivity at different frequency range measured in mV
* Sensitivity is a very crucial factor in infrared sensors and it should be very high and efficient.
* Field of view - the circular range in which the unit can sense radiation
* Type of electrode
* Response time is the time taken by the sensor to detect, sense the object and send response.
* IR sensors are used to build cameras or radiation detecting units, night vision goggles, and security and monitoring equipment.
* IR sensors find usage in process industries where the temperature can be between -30 deg C to 3000 deg C. Some of the process industries are paper, glass, metals, plastics, cement, chemical, food, petrochemical, textiles, etc.
* They also help firefighters to see smoke and save lives. PDAs and other computers and digital cameras use infrared technology to send and receive data.
* They are also used in motion detection and other equipment.