MQ-136 Hydrogen Sulfide Sensor Module MQ136 H2S Gas DetectionArduino

This module is MQ-136 hydrogen sulfide sensor. Please preheat about 20S before use. The first step is to supply 5V direct current to the module (pay attention to the positive and negative poles, otherwise it is easy to burn the chip). If you choose DOUT and TTL are selected, the output signal can be directly connected to the IO port of MCU or a NPN triode to drive the relay. The potentiometer is used to adjust the threshold of output level jump. When the gas is detected by the sensor, the voltage of the two points of the LM393 pin of the comparator and the gas concentration can be detected by the heel sensor. Degree is proportional. When the concentration exceeds the threshold set by the potentiometer RP, the position of the comparator foot 2 is higher than that of the comparator foot 3. At this time, the comparator foot outputs low level, the LED lamp is on, R3 is the current limiting resistance of the LED lamp, C1 is the filter capacitor. Sensor output low level, on the contrary, when there is no signal, sensor output high level, equal to the power supply voltage. If you choose AOUT then you don #39;t need a tube potentiometer. When there is no gas to be measured, the voltage value of the sensor output voltage is set as the reference voltage. At this time, the voltage of the AOUT end is about 1V. When the sensor detects the gas to be measured, The voltage increases by 0.1 V. The actual gas concentration increased by 200 ppm(simply: 1 ppm = 1 mg/kg = 1 mg / L = 1 × 10-6 is often used to indicate gas concentration, or solution concentration. the measured analog voltage value can be converted into a concentration value in a single chip computer. Note: if you are using it for precision instruments, buy the standard calibration instruments on the market, otherwise there is an error because the ratio of output concentration to voltage relationship is not linear, but tends to be linear.