Endurance test (65’000h) with ultrasonic sensors

SNT Sensortechnik AG: Ultrasonic sensors are often used thanks to their advantageous physical principle when, for example, optical sensors do not work properly due to heavy dirt or rough environment. All the more it is important that the sensors electronics and mechanics are tuned for ruggedness and long service life.

SNT Sensortechnik AG has established an endurance test stand in 2004. The devices are permanently turned on and they are checked periodically. Meanwhile, some of the sensors have accumulated 65’000 hours, and they measure the same as on the first day. Besides the electronic components, the ultrasonic transducer is the most critical part. It represents an acoustic diaphragm which is electromechanically excited approx. 30 times per second. The amplitude in the center was measured as a few micrometers. And the transmission duration of one pulse is about 0.1 milliseconds. Thus with a typical ultrasonic frequency of 200kHz the accumulated number of membrane oscillations during the whole endurance test is around 1011. That’s 100 billion oscillations. The membrane, of which one does not perceive that it is moving, has passed 200km forth and to 200km back in this time.

SNT Sensortechnik AG is a specialist in ultrasonic sensors for more than 20 years.