Smart Thermostat with Raspberry Pi

Connect each DS18B20 digital temperature sensor to GPIO pin 4 using the OneWire protocol, with a 4.7kΩ pull-up resistor between the data line and 3.3V. Mount one sensor in the main living area, one near the thermostat location, and one in an attic or basement zone for multi-zone monitoring. Verify each sensor's unique address using a scan script so you can identify which reading comes from which location.

Identify the R (24V power), W (heat call), and Y (cool call) wires on your HVAC system's low-voltage control terminal. Wire the relay module's COM and NO terminals to interrupt the W wire for heating control, and use a second relay channel on the Y wire for cooling. Connect the relay control pins to GPIO 17 (heat) and GPIO 27 (cool) on the Pi, and test with the system powered off by manually toggling relays with a multimeter.

Create a touchscreen interface using Python and PyQt or Kivy that displays the current temperature from all three sensors in large readable fonts. Add circular buttons or sliders to set the target temperature and select between heat, cool, and off modes. Design the layout with a dark theme and high-contrast colors so it is readable from across the room in both daylight and evening lighting.

Log temperature readings and manual adjustments to a SQLite database to build a history of your preferences. Write a simple learning algorithm that detects patterns in when you typically raise or lower the temperature and auto-adjusts the schedule accordingly. Display a weekly schedule view on the touchscreen showing the learned time blocks and allow manual overrides that feed back into the learning model.