The Kitronik Air Quality Control HAT for Raspberry Pi provides a variety of sensor inputs and connection points for the Raspberry Pi and provides the ability to record, store and efficiently view data with the Pi file system and an OLED display. There are also connection points for external devices such as analogue sensors, servo motors, motors and heating pads allowing for additional monitoring and readout-based actions. This HAT is compatible with all versions of the Raspberry Pi that have the 40-pin GPIO connector The HAT can read inputs from a BME688 air quality and environmental sensor (temperature, pressure, humidity, air quality indicator and eCO2). The sensor, along with the RTC on the RP2040 IC and the memory on the Pi means that the board is well prepared for data logging. There is a 128×64 black and white OLED display and 3 ZIP status LEDs for visual display of data, and a piezo transducer for audio Features: Monitor, record and react to collected sensor data, then store and view the data efficiently with the Pi file system and a built-in OLED display Add external devices such as analog sensors, servo motors, motors, and heating pads that enable additional monitoring and readout-based actions Complies with the Raspberry Pi standard for HATs The HAT is powered via the Raspberry Pi’s GPIO connector High power output: GPIO13 & GPIO19 (maximum current draw 1A) Servo motor output control, GPIO6 (power supply voltage) and piezo motor control, GPIO26 Analog inputs (RP2040 ADC): ADC0, ADC1 & ADC2 (each with 3.3V & GND) LEDs ZIP: RP2040) Additional pin junctions: GPIO22, GPIO23, GPIO24 + 3.3V & GND (each with 1.3V & GND) BME688 & OLED screen control: I2C bus (GPIO2 & GPIO3) This HAT is compatible with all versions of the Raspberry Pi that have the 40-pin GPIO connector (Pi 2, 3, 4, 5, Zero and Zero 2). It has been tested with Pi 2, 3, 4, 4, 5 and Zero 2