There are several companies that use vibration and sound to detect faults (condition based monitoring). Otosense was one (now part of Analog Devices). https://

There are several companies that use vibration and sound to detect faults (condition based monitoring). Otosense was one (now part of Analog Devices). https://www.analog.com/en/lp/001/machine-health-sensing.html https://www.analog.com/en/lp/001/machine-health-sensing.html