Hot water boiler temperature measurement system

Here is my simple IOT-device to measure the hot water boiler temperatures and the smoke gas of the wood-burning stove. Code is running on STM32F103 microcontroller. Hot water boiler measurements are made by two DS1820 sensors. Smoke gas is measured by MAX6674 and K-type thermocouple. ENC28J60 module connects MCU to Ethernet, and a really simple HTTP server serves temperatures. I have Linux server reading values once a minute and store them on MySQL database for later use. There is a simple web page to view the day’s current values and history. This is useful for seeing the system’s status without going to the boiler room. My house’s heating is all done by burning wood on that stove, so in cold winter, that means starting fire once a day and adding wood when that fire starts to go out. While working, I can check my web UI to know if my starting fire succeeded and when to add more wood. There are plans of adding some alerts, but that is for a later time.

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Stuff in picture: Green board on center is my general purpose STM32F103 board(just some voltage regulators, capacitors and USB-connector, that is not used in this project). Under that is programmer board. It is for flashing MCU and is removed when development cycle is over. Under that is main board that basically connects all things together. Bottom blue board is Ethernet module, connected to main board. Metal tube on right is K-type sensor and under that is LCD display for displaying values in boiler room.