aoa tone example using voltage input
Take in voltage input from ANALOG_IN_PIN (default to pin 3) and play audio tone
Monitor serial output to check the volatage value and set the following based on what voltages you see
HIGH_TONE_AOA_STALL
HIGH_TONE_AOA_START
LOW_TONE_AOA_SOLID
LOW_TONE_AOA_START
This project is a simpler version of the following. https://github.com/dinglewanker/aoa-tone-efis-serial