This repo contains a few examples that might be handy when we are testing different sensors for our Smart Mailbox - project
Useful links:
Adafruit FONA docs: https://learn.adafruit.com/adafruit-feather-32u4-fona/
Ultrasonic sensor: https://create.arduino.cc/projecthub/Nicholas_N/distance-measurement-with-an-ultrasonic-sensor-hy-srf05-64554e
IR sensor: https://create.arduino.cc/projecthub/Raushancpr/arduino-with-ir-sensor-1579b6
Hall effect: https://maker.pro/arduino/tutorial/how-to-use-a-hall-effect-sensor-with-arduino