Logging of Servo Input Signal for additional sensors

Dear list

Is there a way to log the servo input signal of an AUX pin? No downlink to GCS is needed.

Background of this question is the following:
I have to log air temperatur and humidity during the flight. The signal of the sensors could be converted into an analog signal and forwarded to an input pin (e.g. 0 - 5V in steps of 1 mV).

Questions:

  • Is this principally possible?
  • What kind of input signal (DC) is needed?

Looking forward to any hint