I wrote some small test programms for all parts of the T-Beam
LoraReceiver
LoraSender
DisplayTest
GPSTest
ButtonTest
BatteryStatusTest
BatteryStatusDisplay
https://github.com/sandeepmistry/arduino-LoRa
https://github.com/ThingPulse/esp8266-oled-ssd1306
https://github.com/knolleary/pubsubclient
https://github.com/mikalhart/TinyGPSPlus
https://github.com/lewisxhe/AXP202X_Library
Created by S. Fambach visit https://www.fambach.net if you want