Bernd has done some very experimental support for the low power nRF52 which he was happy to share He wrote --------- Just for fun, I ported the DisasterRadio sources to work on a Nordic nRF52 board. Of course there is no WiFi at all with the nRF52, but they are fantastic in low power consumption. In another (customer) project I have a nRF52 with a Semtech SX1262 LoRa running for 5 days from a 1000mAh battery while sending LoRa packages every 30 seconds. The code is working with some restrictions: - Only BLE or Console to connect to the node - Only tested with an Semtech SX126x LoRa transceiver, I have no RFM95 modules. - No SD card history support - No OLED support (working on it, needs a different library) - LoRa layer 2 hash support disabled (not used at the moment anyway) because the nRF52 has not enough RAM to hold the (very big == 10kB) table for it. - no GPS support because the nRF52 has only one HardwareSerial and I didn't try the SoftwareSerial yet. Sources are up. https://github.com/beegee-tokyo/Disaster-Radio-BLE---nRF52832 Please make sure you keep the lib folder, because there is an adapted LoRaLayer2 file. You will have to adapt the platformio.ini file. Right now the nRF52 has a USE_SX1262 flag. To run it with a RFM95 board you have to remove that and adapt config.h with your GPIO settings. ----------- I think this might work with https://coolcomponents.co.uk/products/adafruit-feather-nrf52-bluefruit-le-n… and Kind of related to the Wind discussion, in so far as the cheapest energy you'll get is efficiency.. Thanks Sam