jabbado:
Have you seen this app note?Mixed-signal and digital signal processing ICs | Analog Devices
Thanks for this link. I think it is very similar to what I am proposing, possibly the only difference is the frequency at which we need to emit the Ping. which is 1kHz. This is the reason I've opted to use Arduino libraries instead of the 40kHz Ping sensor.Thanks again.
PeterH:
Your acoustic sensor would be enclosed in Helium?
Yes, it will be positioned somewhere near the center of the balloon. The only way that Helium changes the project versus dry air is the constants which are used during the Temperature calculation. Sound Speed is still calculated the same way.