Room thermostat with PIC16F74, DS1820, and the Siemens M55 color LCD:
The heart of the unit is an 8 bit PIC16F74 microcontroller from Microchip. It’s main task is to constantly monitor the room temperature trough a 1–wire digital thermometer IC, a DS1820 from Maxim, and to switch a relay on or off, that controls the gas boiler accordingly. The system also features a color LCD, which was removed from an old mobile phone, a few LED’s, an LDR sensor for night mode and a couple of pushbuttons
Via Electronics Lab.