OpenWrt is an open source project for embedded operating system based on Linux, primarily used on embedded devices to route network traffic. I install OpenWrt on my Netgear DGN3500, an ADSL2+ gateway with wireless acccess point integrated. Finally the wifi signal is strong but the internet connection does not go up at boot or after a disconnection.
The sensor uses an ESP8266 board with the protocol Lightweight M2M to communicate the temperature read by DS18B20 to the gateway. The sources of the project are available on GitHub: https://github.com/brusdev/smart-solar-heating-system/tree/master/sensor ESP8266 The ESP8266 is a low-cost Wi-Fi microchip with full TCP/IP stack and microcontroller capability produced by Espressif Systems. The avalability of same SDK allows the chip to be programmed, removing the need for a separate microcontroller. To program the microchip i use the SDK Arduino core for ESP8266 WiFi chip and PlatformIO , that is an open source ecosystem for IoT development. LwM2M Lightweight M2M is a protocol from the Open Mobile Alliance for M2M or IoT device management and communication. It uses CoAP, a light and compact protocol with an efficient resource data model, for the application layer communication between LWM2M Servers and LWM2M Clients. Each service on a constrained device/sensor/actor is