The idea for this sonde is a minimal cost system that transmits data to ground from at least 5000ft. The device should be recoverable and reusable. 

The desired measurements are as follows:

• Temperature
• Pressure
• Humidity
• Wind Strength
• Wind Direction

P/T/H can be accomplished with a single chip such as the BME280.

Wind measurements can be derived with some accuracy using a GPS and integrating the movement of the system as it falls.

The descent rate of the system will provide the time for GPS movement, but with some caveats; the slower the sonde descends, the more it will drift. A balance needs to be struck between ease of retrieval and  measurement quality.