Ultrasonic sensors detect all sound-reflecting objects. To calculate the distance, they measure the time between sending and receiving a reflected sound signal. The target’s colour, transparency and surface reflectivity are irrelevant.
This chart rates the performance of various technologies with certain influences.
Ultrasonic | Inductive | Capacitive | Photoelectric | |
---|---|---|---|---|
Great distance to the object | ||||
Independent of colour / transparency | 1 | |||
Independent of material | ||||
Temperature fluctuations | ||||
Deposits on the sensor | 2 | 3 | ||
Extraneous light immunity | ||||
High ambient humidity |
1) e.g. thin, clear-transparent film/glass
2) if not excessive
3) if non-conductive