Detection based on “ultrasonic”
Comparison between ultrasonic / level sensors and optical sensors

Outline and detection principle

Comparison between optical sensors (reflective model) and ultrasonic / level sensors

Typical sensors used for distance measurement are optical sensors.
The following table shows the advantages and disadvantages when optical sensors and ultrasonic / level sensors are compared.
Note that this table is based on KEYENCE products.

Item Optical (reflective model) * Ultrasonic
Detectable target Detection is affected by target materials/colours Detection is unaffected by target materials/colours
Detecting distance 1000 mm max. 10 m max.
Accuracy High Low
Response speed Fast Slow
Dust/water Affected Unaffected
Measuring range Small Large
Item Optical (reflective model) * Ultrasonic
Detectable target Detection is affected by target materials/colours Detection is unaffected by target materials/colours
Detecting distance 1000 mm max. 10 m 32.8' max.
Accuracy High Low
Response speed Fast Slow
Dust/water Affected Unaffected
Measuring range Small Large

* Excluding the Time of Flight (TOF) type

What is ultrasonic?

“Ultrasonic” generally refers to a “high pitch sound that is inaudible to humans.” Sound is expressed by a unit called frequency (Hz). The greater the frequency, the higher the pitch of sound becomes. The unit Hz (hertz) means the number of oscillations per second. For example, a wave that oscillates 100 times in a second is expressed as 100 Hz. The audible range for humans is said to be between about 20 Hz and 20 kHz. In other words, ultrasonic waves have a frequency of 20 kHz or greater.

Familiar examples of devices using ultrasonic waves

In our ordinary life, the following ultrasonic / level sensors are used:
・Fish detector (used for fishery or bass fishing)
・Active sonar in a submarine (used for finding enemy submarines or battle ships)
・Back sonar for cars
(for detecting obstacles during backing a car to prevent single-car accident)

INDEX

See the details of actual products from here.

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