Detecting smoke

In this section, we will test an MQ135 sensor which can detect smoke. This could also be used in a home to detect a gas leak. In this case, we will use it to detect smoke.

In home automation systems, putting all the sensors to detect something at home, we measure the real world: in this case we used the MQ135 sensor which can detect gas and smoke, as shown in the following image:

Software code

In the following code, we explain how program and detect smoke using the gas sensor:

const int sensorPin= 0; 
const int buzzerPin= 12; 
int smoke_level; 
 
void setup() { 
Serial.begin(115200);  
pinMode(sensorPin, INPUT); 
pinMode(buzzerPin, OUTPUT); 
} 
 
void loop() { 
smoke_level= analogRead(sensorPin); 
Serial.println(smoke_level); 
 
 
 
if(smoke_level > 200){  
digitalWrite(buzzerPin, HIGH); 
} 
 
else{ 
digitalWrite(buzzerPin, LOW); 
} 
} 

If it doesn't detect...