5.4 Circuit connection
- Collect all the components required :
- Node MCU
- MQ-135 Gas sensor
- Jumper wires
- Micro USB cable
2. Now, connect Mq135 sensor with Node MCU.
As you can see MQ 135 sensor have four pins:
- Analog Output(A0)
- Digital Output (D0)
3. Connect the Vcc pin of the gas sensor to Vin pin of Node MCU.
4. Connect the GND pin of gas sensor to GND (G) pin of Node MCU.
5. As, we have to measure the concentration of gases so, we will use the analog output.Now, Connect the A0 pin of gas sensor to A0 pin of Node MCU.