A timegrapher listens for several sounds made by the escapement such the locking and unlocking of the pallet jewels. Using the lift angle input by the user the timegrapher is able to calculate the amplitude based on the spacing between the sounds.

 

The app is fun, but the Timegrapher is real........

 

Timegraphers need to be told the movement's lift angle to calculate amplitude correctly.

In very layman's terms, there are several impulse sounds in the escapement and the timegrapher listens to them and records the time between them (there are sounds ehen the pallet fork hits the escape wheel as well as the balance contacting the pallet fork). Knowing the time between the 1st and 3rd impulse sound and the lift angle, amplitude can be calculated.

 

Thanks guys, looks like I have some reading to do, but that looks like a good high level explanation. I wonder if it's possible to add amplitude to an app, or is the mic in an average cell phone not good enough to resolve the sounds necessary to determine it?

 

I've tried several timegrapher apps on the phone, but they seemed to give rather poor results compared to my 150€ standard No. 1000 timegrapher. To me, the device really pays for itself very quickly, by avoiding premature servicing or by checking the quality of used / grey market watches you might still return for a refund if they show signs of trouble, etc.

 

The timegrapher, IMHO, gives a close approx of the running of the watch. Beat error and amplitude are more useful than the spd since on the wrist it is often different. Also, my AD's machine gives different results, and a week later, results a couple of seconds different.

 

Nice replies, all. These are the kinds of responses that make it worth surfing through random threads.

 

This may help getting the correct lift angle.

and this one may help too.