ESP8266 ADC – Read Analog Values

ESP8266 have ONE ADC pin that is easily accessible. This means that those ESP8266 boards can read analog signals. In this tutorial we’ll show you how to use analog reading with the ESP8266 using Arduino IDE.

ESP8266 ADC Specifications

10-bit resolution, which means you’ll get values between 0 and 1024.
Voltage range in ESP8266 development boards: 0 to 3.3V.
Pin: A0

Diagram

Arduino Script

const int analogInPin = A0;  // ESP8266 Analog Pin ADC0 = A0

int sensorValue = 0;  // value read from the pot
int outputValue = 0;  // value to output to a PWM pin

void setup() {
  // initialize serial communication at 115200
  Serial.begin(115200);
}

void loop() {
  // read the analog in value
  sensorValue = analogRead(analogInPin);
  
  // map it to the range of the PWM out
  outputValue = map(sensorValue, 0, 1024, 0, 255);
  
  // print the readings in the Serial Monitor
  Serial.print("sensor = ");
  Serial.print(sensorValue);
  Serial.print("\t output = ");
  Serial.println(outputValue);

  delay(1000);
}

ESP8266