Main parts of devices are Microcontroller Unit (MCU) and sensors. Wide variety of MCUs and sensors can be used (LINK). The devices have low power consumption and are mostly powered by LiPo battery charging by small solar cells. Sensors are connected to MCU via data bus.
Data from devices are periodically transmitted (particularly using LoRa Radio Network) to data servers or data cloud. There is data stored and can be displayed via web interfaces.