ESP8266 Community Forum

Hello everyone, I am trying to build a carbon monoxide sensing device. I am using an ESP8266:

https://www.amazon.com/gp/product/B081C ... =UTF8&th=1

and an MQ-7 sensor: https://www.robotshop.com/en/mq-7-gas-sensor.html

I am trying to read data from the analog and digital ports and display the information on the serial monitor on the Arduino IDE. However, I keep seeing the error messaged that I attached.

This is my code:



const int AOUTpin=0;
const int DOUTpin=8;

int limit;
int value;

void setup() {
Serial.begin(115200);
pinMode(DOUTpin, INPUT);

}

void loop()
{
value= analogRead(AOUTpin);
limit= digitalRead(DOUTpin);
Serial.print("CO value: ");
Serial.println(value);

delay(100);

}

For my connections,
ESP8266 VIN to MQ-7VCC
ESP GND to MQ-7 GND
ESP D0 to MQ-7 DOUT
ESP A0 to MQ-7 AOUT

How do I fix this?