Introduction to MQ-135 sensor:
The gas sensing material used in the MQ135 gas sensor is tin dioxide (SnO2) with lower conductivity in clean air. When the sensor is in the environment
When polluting a gas, the conductivity of the sensor increases as the concentration of the polluting gas in the air increases. Change the conductivity with a simple circuit
The conversion is converted to an output signal corresponding to the gas concentration.
The MQ135 sensor is highly sensitive to ammonia, sulfides, and benzene vapors, and is ideal for monitoring smog and other harmful effects. This kind of sensor can be checked
Measuring a variety of harmful gases is a low-cost sensor for a variety of applications.
Harmful gas detection device for household and environment, suitable for detection of harmful gases such as ammonia, aromatics, sulfides, benzene vapors, smoke, etc., gas-sensitive components test concentration range: 10 to 1000ppm
Explanation: Please preheat about the 20S before use.
The first step: supply 5V DC to the module (note that the positive and negative poles are not connected, otherwise it is easy to burn the chip).
Step 2: If DO, TTL high, and low-level output is selected, the output signal can be directly connected to the IO port of the MCU or connected to the relay module. The potentiometer is used here to adjust the threshold of the output level transition.
The third step: If you choose AO, analog output, then you do not need to control the potentiometer, directly connect the AO pin to the input of AD conversion or the microcontroller with AD function. According to our experience: in the normal environment, that is, the environment without the gas to be measured, set the sensor output voltage value as the reference voltage. At this time, the voltage at the AO terminal is about 1V. When