This sensor is a recent development for the person who is not necessarily a watchmaker, but a collector with a true passion for "haute horologerie" possibly costing hundreds of thousands of dollars.
The treasured piece can just be laid on the soft pads and a small aluminium feeler transmits the sound to the detector. The performance is determined and can be recorded or listened to in real time. Amplitude is an excellent indicator of overall health so can be tracked and easily used as a basis for deciding when a service is due.
The tick on these can sometimes be hard to hear but with eTimer you can savour every beat. Click on the audio player below to hear the actual recording.