Self-cleaning ultrasonic sensors

A method implemented by a sensor controller for a sensor, the method comprising:

• driving a piezoelectric transducer to generate a short acoustic burst for obstacle detection or distance measurement, the short acoustic burst having a length less than or equal to 4 ms;
• obtaining a receive signal to monitor for reflections of the short acoustic burst within a measurement interval associated with the short acoustic burst, the measurement interval being greater than 50 ms;
• and
• operating to clean the sensor by driving the piezoelectric transducer to generate a long acoustic burst at a resonant frequency of the piezoelectric transducer, the long acoustic burst having a length exceeding half of the measurement interval.

A sensor controller that comprises:

• a transmitter configured to drive a piezoelectric transducer to generate an acoustic burst;
• a receiver coupled to at least one of the piezoelectric transducer and a microphone to detect a reflection of the acoustic burst within a measurement interval associated with the acoustic burst, the measurement interval being greater than 50 ms;
• and
• a microcontroller configured to control a length of the acoustic burst to be less than or equal to 4 ms when operating to detect the reflection, the microcontroller setting a longer acoustic burst length when operating to clean the sensor, the longer burst length exceeding half of the measurement interval.