Measure movement performance

Introduction

If you want to really understand the performance of a mechanical watch, you connect it to a gizmo that listens to the ticks and produces various metrics - [beat rate], [amplitude], [isochronism] and the like. The state of the art are by Swiss company Witschi:

As you can see, the watch is held in a springloaded clamp, pressed against a contact microphone. This allows the watch to be held in different orientations, which causes different run rates and can expose any problems in the movement.

From this page, this is what its hearing:

(As alternative, Chinese company TYMC is the same functions for less, but still around $400 for the most basic unit.)

I want something that connects to the computer, so that I can automate the process and get the data online. Right now, I'm looking at Bryan Mumford's sensors. So far, I have the $40 basic sensor:

It works, but the noise is pretty bad and there's only one orientation. On the plus side, the sensor simply plugs into your sound card, so there's no additional cost other than software. Which I'm starting to write.