Blackpill using Arduino IDE

[weiiii22]

Good day all, I would like to ask, can analogRead be used in the Arduino IDE to read the reading from the MQ-2 gas sensor? When I unplug the sensor, the reading should be 0, but the LCD still shows a value. How can I fix it?

Here are my code,

#include <LiquidCrystal_I2C.h>

#define gasSensorPin PA0
#define buzzerPin PB2

LiquidCrystal_I2C lcd(0x27,16,2);
void setup() {
  // put your setup code here, to run once:
  lcd.init();
  lcd.backlight();

  Serial.begin(9600);
  pinMode(gasSensorPin,INPUT);
  pinMode(buzzerPin,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  int sensorValue = analogRead(gasSensorPin); // Read the analog value from the gas sensor
 
  // Display the readings on the LCD
  lcd.setCursor(0, 0);
  lcd.print("Gas Sensor:");
  lcd.print(sensorValue);


  if(sensorValue>15){
    digitalWrite(buzzerPin,HIGH);
  }
  else{
    digitalWrite(buzzerPin,LOW);
  }

  delay(1000);
}

thanks.

[MBertocchi]

This is only STM32 Community! Not Arduino.

[weiiii22]

BLACKPILL is stm32 also cannot ask?

[STTwo-32 · Accepted solution]

Hello @weiiii22 and welcome to the ST Community.

If you are using an STM32 with the STM32duino, you can report your problems in this forum: https://www.stm32duino.com/

Best Regards.

STTwo-32.

[MM..1]

Ohh absurd replies... 

int sensorValue = analogRead(gasSensorPin);

have no way to get if value is valid or sensor is connected. Control this is your job as designer.

Exist more ways , most simple is use range of valid values and all other remove as invalid etc.