It's an IoT DIY project which notifies you when you have received a parcel or a letter in your letterbox. This project uses an HelTec AB01 LoRaWAN module to send data over an LoRaWAN Gateway when WiFi is out of range. I use an Helium Gateway from the People's Network in order to forward packets over Helium Network which send data to AWS IoT Core (MQTT) or Pipedream (HTTP) and more. LoRaWAN is a bidirectional protocol useful when you need to send few data over long distance from low-power and low-bandwidth IoT.
Bresser 5-in-1/6-in-1 868 MHz Weather Sensor Radio Receiver based on ESP32 and RFM95W/SX1276 - sends data to a LoRaWAN Network (e.g. The Things Network)
WisBlock Kit 1 Weather Station is a project that uses a RAK4631 LoRa module in order to transmit data (Temperature, Pressure, Luminosity and Humidity) over an Helium Gateway (RAK Miner V2) that relays data to an Helium router that dispatches the data to the platforms MyDevices Cayenne and Ubidots.