Waveshare MQ-135 Gas Sensor Overview 1. Sensitive for benzene, alcohol, smoke 2. Output voltage boosts along with the concentration of the measured gases increases 3. Fast response and recovery 4. Adjustable sensitivity 5. Signal output indicator Specifications 1. Power: 2.5V ~ 5.0V 2. Dimension: 40.0mm * 21.0mm 3. Mounting holes size: 2.0mm Applications Air quality monitor How to Use In the case of working with a MCU: 1. VCC: 2.5V ~ 5.0V 2. GND: Power supply ground 3. AOUT: MCU.IO (analog output) 4. DOUT: MCU.IO (digital output) Package Contents 1. MQ-135 Gas Sensor x1 2. 4-pin custom connector jumper wire x1 Tips: We sincerely hope that you can leave your Comment and share your experience of using the product so that more friends can know about it.