A long time ago, in a galaxy far, far away, I created an altitude and airspeed data logger. It was a project that I did for one of my university courses.
At that time, I designed the system around the venerable Motorola HC11 microprocessor. I used their MC68HC11EVBU Universal Evaluation Board. I still have the project all together. This is what it looks like today:
Here is a close up of the sensor section:
Here is the schematic for the SensorBlock.
Here is the schematic for the MonitorMemory.
And if you are courageous, here is my project report: EE498 Report – An Airspeed and Altitude Data Logger (2014)