IR Proximity infrared sensor
An infrared sensor is an electronic instrument which is used to sense certain characteristics of its surroundings by either emitting and/or detecting infrared radiation. Infrared sensors are also capable of measuring the heat being emitted by an object and detecting motion.
IR Sensors work by using a specific light sensor to detect a select light wavelength in the Infra-Red (IR) spectrum. By using an LED which produces light at the same wavelength as what the sensor is looking for, you can look at the intensity of the received light. When an object is close to the sensor, the light from the LED bounces off the object and into the light sensor. This results in a large jump in the intensity, which can be detected using a threshold.
Since the sensor works by looking for the reflected light, it is possible to have a sensor that can return the value of the reflected light. This type of sensor can then be used to measure how “bright” the object is. This is useful for tasks like line tracking.
The Types of Infrared Sensors
Infrared sensors are of two types:
- Thermal infrared sensors – use infrared energy as heat. The intensity of the photo depends on the wavelength of the object, which is to be detected. Thermal detectors do not require cooling but do have slow response times and low detection capabilities.
- Quantum infrared sensors – provide higher detection performance and faster response speed. The sensitivity of photo depends on the wavelength. It is necessary to cool Quantum infrared sensors in order to obtain accurate measurements.
- Night vision
- Gas detectors
- Water analysis
- Anesthesiology testing
- Petroleum exploration
- Rail safety
The wavelengths of these regions and their applications are shown below.
- Near-infrared region — 700 nm to 1400 nm — IR sensors, fiber optic
- Mid-infrared region — 1400 nm to 3000 nm — Heat sensing
- Far infrared region — 3000 nm to 1 mm — Thermal imaging
The frequency range of infrared is higher than the microwave and lesser than visible light.