MQ-135 Gas Sensor Module (Ammonia, Sulfide, Benzene)

Description: 

MQ135 gas sensor sensitive material used in the clean air low conductivity tin oxide (SnO2). When the sensor in the environment exist 
in polluting gases, conductivity sensor with increasing air pollution in the gas concentration increases. Using a simple circuit to change the conductivity 
of the gas is converted to an output signal corresponding to the density. 
MQ135 sensor for ammonia, sulfide, benzene vapor high sensitivity, smoke and other harmful monitoring is also very good. This sensor can detect a 
variety of harmful gases measured, is a low-cost sensors for a variety of applications.

Module Application: 
for household hazardous gas detection devices, the environment, suitable for ammonia detection of aromatic compounds, sulfur compounds, benzene vapors, fumes and other gases harmful gases, gas sensors tested concentration range: 10 to 1000ppm 
module features : 
1, using high-quality dual-panel design, with power indicator and a TTL signal output instructions; 
2, with DO switching signal (TTL) output and analog output AO; 
3, TTL output valid signal is low. (When the output low signal light, can be directly connected microcontroller or relay modules) 
4, the higher the voltage, the higher the concentration of the analog output voltage. 
5, air quality, hazardous gas detection has better sensitivity. 
6, there are four screw holes for easy positioning; 
7, the product Dimensions: 32 (L) * 20 (W) * 22 (H) 
8, has a long life and reliable stability 
9, rapid response and recovery characteristics

Electrical performance: Input voltage: DC5V Power (current): 150mA DO output: TTL digital 0 and 1 (0.1 and 5V)


AO Output: 0.1-0.3V (relatively clean), about the highest concentration voltage 4V 
Special note: Sensors Power, the need to preheat about 20S, measured data becomes stable, sensor fever is a normal phenomenon, because the internal electric wire, if not normal hot.

Wiring: 1, VCC: positive power supply (5V) 2, GND: power supply is negative 3, DO: TTL switching signal output 4, AO: analog output

Test program:

Function: This version of the package test program

Using the chip: AT89S52

Crystal: 11.0592MHZ

Baud Rate: 9600

Build environment: Keil

[Statement] This procedure is used only for study and reference, quoted, please indicate the copyright and author information!

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Description: 1, when the measured concentration greater than the set concentration, the microcontroller IO port output low

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#include // library files

#define uchar unsigned char // unsigned char macro definition

#define uint unsigned int // macros unsigned integer

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I / O definition

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sbit LED = P1 ^ 0; // define the microcontroller port P1 first one (ie P1.0) to indicate the end

sbit DOUT = P2 ^ 0; // define SCM P2 mouth first one (ie P2.0) as an input sensor

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Delay function

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void delay () // delay procedure

{

uchar m, n, s;

for (m = 20; m> 0; m--)

for (n = 20; n> 0; n--)

for (s = 248; s> 0; s--);

}

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The main function

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void main ()

{

while (1) // infinite loop

{

LED = 1; // P1.0 port lights go out

if (DOUT == 0) // When the concentration is higher than the set value, the condition function

{

delay (); // delay interference

When if (DOUT == 0) // determine the concentration higher than the set value, the condition function

{

LED = 0; // P1.0 port lights lit

}

}

}

}

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