Air Quality Detect Introduce Input Formaldehyde (HCHO): Dart WZ-S-K sensor Volatile organic compounds (VOCs): CJSL 3in1 VOC sensor Output Screen: LCD1602(with HD44780 controller) + PCF8574T i2c bus expander Presist SQLite3 Platform Hardware: Raspberry Pi with 40-pin GPIO License Licensed by MPL-2.0