【P2009001】MQ series gas sensor module

Module introduction:

1. Gas sensor module, sensors: MQ2, MQ3, MQ4, MQ5, MQ6, MQ7, MQ8, MQ9, MQ135, etc.;
2. 5V power supply;
3. With DO switch signal (TTL) output and AO analog signal output;
4. The TTL valid signal bit is low level. When the output signal bit is low level, the signal light is on. It can be directly connected to a microcontroller or relay module;
5. The voltage of analog output, the higher the concentration, the higher the voltage;
6. Green LED light-emitting diode power indicator light;
7. Circuit board size: 22mm×40mm;
8. Model: TR02

Because MQ2, MQ3, MQ4, MQ5, MQ6, MQ7, MQ8, MQ9, and MQ135 can share the circuit board, there is no need to change other circuit parameters, so the circuit board is just in place. This time, 30 pieces were made, as follows Posted 10 pieces.

The following are various gas sensors of MQ2, MQ3, MQ4, MQ5, MQ6, MQ7, MQ8, MQ9, MQ135

Welded MQ2 module

circuit analysis

VCC is a 5V voltage, which cannot be lower than 5V, because the voltage used to heat the gas sensor is 5V±0.2V, which provides a specific operating temperature for the sensor; AO is an analog output, and the actual measurement is about 0-4.5VDC. The MCP6002 is used here. , you cannot use LM258 or LM358 (because when powered by 5V, the maximum voltage output by LM358/LM258 is about 3.5V). The function of MCP6002 as a comparator is used here. When the AO voltage is higher than the voltage of pin 2, pin 1 When the AO voltage is lower than the voltage of pin 2, pin 1 outputs low level, Q1 does not conduct, DO outputs high level, and LED2 does not light up.