Arduino Pro Mini TTN LoRaWAN Node with DoorSwitch and SX1276 Lora module.
The Arduino can be converted to LowPower by desoldering the power LED and the voltage converter.
see payload_formatter folder
.pio\libdeps\pro8MHzatmega328\MCCI LoRaWAN LMIC library\project_config\lmic_project_config.h
#define CFG_eu868 1
#define CFG_sx1276_radio 1