Sorry for my slow responses...
@jisham Fabulous, thanks a lot for sharing this!
@booBot To shorten the calibration period, which makes sense if you have a very clean signal to calibrate with, assuming that you can compile tg form the source code, it suffices to change this line in the file src/tg.h
The number 900 represents roughly the number of seconds of signal needed for the calibration, so with 900 it will take about 15 minutes. If you need it and you are unable to do the compilation, just drop me a PM and I will see what I can do for you...
#define CAL_DATA_SIZE 900
edit: @blackarrow Ambient noise should not be a major issue, as long as you are in a relatively quiet environment. If you can, I would suggest to keep the watch in contact with the microphone, and otherwise as close as possible. Always keep in mind that mechanical watches are sensitive to magnetism, this is not a problem with piezo or capsule (electret) microphones, but magnets are used to keep the lid of certain laptops closed, so, if you are using a laptop, check first (just see if it attracts a paper clip or a needle).