Reverse-Engineering the LCD Display Interface of the Nest 2nd Gen Thermostat
2 days ago
- #Nest-thermostat
- #reverse-engineering
- #LCD-display
- Reverse-engineered the LCD display interface of the Nest 2nd Gen thermostat.
- Discovered the LCD module part number 'TM025ZDZ02' after disassembly.
- Found a similar module, TM025ZDZ01, with nearly identical specifications.
- Designed a breakout board to convert the 41-pin FPC connector to standard pins.
- Implemented a 3-wire SPI interface with 9-bit transfers for the display.
- Solved bus contention with a current-limiting resistor.
- Initialized the display using a detailed command sequence from the datasheet.
- Addressed performance challenges with 9-bit SPI transfers.
- Powered the backlight with an adjustable boost converter.
- Integrated all components into a working prototype.
- Aimed to prevent Nest 2nd Gen thermostats from becoming e-waste with the Sett project.