This is an Arduino wrapper for MicroAPRS in SerialMode from https://github.com/markqvist/MicroAPRS
Serial Protocol is enabled in https://github.com/markqvist/MicroAPRS/blob/master/Modem/config.h
change from
#define SERIAL_PROTOCOL PROTOCOL_SIMPLE_SERIAL
//#define SERIAL_PROTOCOL PROTOCOL_KISSto
//#define SERIAL_PROTOCOL PROTOCOL_SIMPLE_SERIAL
#define SERIAL_PROTOCOL PROTOCOL_KISSmake it new and flash the firmware on you Arduino238p
As an example the code will transmit the humidity and temperature values from an DHT11 sensor as Comment via APRS
APRS is a registered trademark of APRS Software and Bob Bruninga, WB4APR.