Infrared light has long wavelengths (700-1000nm)
- Invisible to human eyes
Reflectance sensing hardware
- The emitter is usually made with an LED, and the detector is usually a photodiode/phototransistor
Working principle:
- Measure distance by the intensity of reflected light
- It can measure ambient light (without emission) and subtract it from the reflected light
Application and weaknesses:
- Common usage: cheap robots
- Disadvantage: depends on object characteristics, e.g. shape/color