Code for a TTNMapper node with GPS running on a Heltec "WiFi Lora32 V2" node, based on Heltec-Wifi-Lora-32-TTN-Mapper by sistemasorp

• Copyright (c) 2015 Thomas Telkamp and Matthijs Kooijman: https://github.com/matthijskooijman/arduino-lmic/blob/master/examples/ttn-abp/ttn-abp.ino
• Copyright (c) 2018 sbiermann: https://github.com/sbiermann/Lora-TTNMapper-ESP32
• Copyright (c) 2019 sistemasorp: https://github.com/sistemasorp/Heltec-Wifi-Lora-32-TTN-Mapper
• Copyright (c) 2020 noppingen: https://github.com/noppingen/Lora-TTNMapper-Heltec-v2/

• More diag output on serial interface
• Stay quiet, LoRa TX only if GPS HDOP is below a certain limit
• Vext is initialized during start, you may connect the GPS to Vext
• Display of distance to your mapped "home" gateway

• Add required libraries
• Set TTN NWKSKEY, APPKSKEY and DEVADDR
• Set GPS_RX and GPS_TX
• Set gateway GPS coordinates to get the distance displayed on your way
• Set TX_INTERVAL, HDOP_MAX and TX_WAIT_INTERVAL
• Change bands if you are not in the EU868 region
• Print my case: Thingiverse

• Activation method is set to ABP
• TTN decoder script is here