02-07-2020, 06:07 PM
Woooow thanks a lot, I'm impressed by the effort you put in this forum!
I didn't know the editor, it opened me a world. I'll try to explore. Maybe i'll find the solution by myself, but you seems very kind and interested, so I share here my experiment.
I would like to collect like 10 smartphones and put them on the ground spaced by, let's say, 10 meters each, coupled with the ground, as they were geophones.
Then, I do a shot on the ground with a big hammer near smartphone #1, and if sufficiently strong its seismic waves should be recorded by every smartphone far away. It's like a seismic survey, i don't know if you are familiar with. In any case, the time at which the seismic waves arrive at each phone is very important, and I want to record it with precision: it depends on the wave speed that is different for each type of soil. 10 accelerometers at 500 Hz are ok.
The problem is: every smartphone has it's clock, so I have to give them a common and known impulse to set a common starting time: a sound impulse seemed great because I know it's speed (340 m/s) so, after little computation, I can easily define a common starting time of all smartphones who detected the sound impulse.
So, I don't need much audio information, I don't mind of audio quality, I only would like to detect a strong initial impulse (audio sampling rate should be similar to that of accelerometer (500 Hz is great)
if you have some idea, i'll explore them.
Thank you very much, have a nice weekend!
Andrea
I didn't know the editor, it opened me a world. I'll try to explore. Maybe i'll find the solution by myself, but you seems very kind and interested, so I share here my experiment.
I would like to collect like 10 smartphones and put them on the ground spaced by, let's say, 10 meters each, coupled with the ground, as they were geophones.
Then, I do a shot on the ground with a big hammer near smartphone #1, and if sufficiently strong its seismic waves should be recorded by every smartphone far away. It's like a seismic survey, i don't know if you are familiar with. In any case, the time at which the seismic waves arrive at each phone is very important, and I want to record it with precision: it depends on the wave speed that is different for each type of soil. 10 accelerometers at 500 Hz are ok.
The problem is: every smartphone has it's clock, so I have to give them a common and known impulse to set a common starting time: a sound impulse seemed great because I know it's speed (340 m/s) so, after little computation, I can easily define a common starting time of all smartphones who detected the sound impulse.
So, I don't need much audio information, I don't mind of audio quality, I only would like to detect a strong initial impulse (audio sampling rate should be similar to that of accelerometer (500 Hz is great)
if you have some idea, i'll explore them.
Thank you very much, have a nice weekend!
Andrea