Hookup Guide
Schematic
Datasheet (GM-302B)Product Overview
The SparkFun Qwiic Alcohol/Ethanol Gas Sensor is a compact and solderless solution for measuring ethanol (CH3CH2OH) gas concentrations in indoor environments. Utilizing the Winsen GM-302B MEMS sensor, it detects concentrations between 1 and 500 parts per million (ppm), routing the sensor's analog voltage fluctuations into an onboard 10-bit analog-to-digital converter (ADC) that delivers a clean digital signal directly over I2C.
Qualitative Measurement & Calibration
While the GM-302B measures ethanol concentration, it returns only qualitative data; the data does not represent a specific concentration in ppm.
- Built-in ADC: The onboard 10-bit analog-to-digital converter takes the sensor's raw analog voltage output (with a sensitive material resistance of 1KΩ to 30KΩ) and feeds the converted data to your microcontroller over I2C (default address 0x52).
- Sensor Calibration: Because the baseline values are uncalibrated and can experience some crossover with other gases, you'll need to calibrate the output against known concentrations of ethanol to extract useful ppm data.
- Operation Efficiency: Includes an onboard LDO power regulator configured to power the internal sensor heater with an 80Ω ±20Ω room-temperature resistance that consumes less than 50mW of power.
This breakout features a pair of Qwiic connectors for a completely solderless setup and works directly with the SparkFun GM-XX2B Arduino Library. For users who prefer a traditional breadboard circuit or need direct access to the analog signal, standard 0.1-inch-spaced plated through-hole (PTH) pins break out the 3.3V power, I2C lines, ADC Alert signal, and the sensor's raw VOUT signal.
