Analog to Digital Conversion using ESP8266

Analog to Digital Conversion

The datasheet describes the ADC pin as having 10 bit resolution. This means 0 to 1024. You should get a value somewhere within this range.

Here the fun begins! Apparently, the module only converts voltage between 0 and 1 volt.

As an example, I have a 10k rheostat hooked up to the ADC pin. Fully moving the slider to the position where I would expect a 0 reading, the ADC TOUT pins reads 13~15, not 0 but encouraging!

However, as I slide the slider to the right, I see the ADC TOUT reaches the maximum reading of 1024 in about 1/3 the distance.

Ideally, I want the slider to register 0 to 1024 increasing or decreasing over 100% of the slider travel.

Reaching the maximum reading in 1/3 of the travel makes sense, the ADC pin only reads up to 1 volt. Any reading over that, say 1.1v to Vcc of 3.3v will be maxed out to 1024.

So, I need to supply the ADC pin a voltage between 0 and 1 volt only.

Using a voltage divider greatly improves the situation.

Voltage Divider 

Source Code 

void setup() {

  // put your setup code here, to run once:

  Serial.begin(115200);

}

void loop() {

  // put your main code here, to run repeatedly:

Get_Anolog_Process();

delay(100);

}

int ADC_Sum=0;

int Battery_Value=0;

int ADC_Count=0;

int Round_OFF=0;

void Get_Anolog_Process(void)

{

 

       ADC_Sum+=analogRead(A0);ADC_Count++;

        if(Battery_Value==0){

            Battery_Value=(int)(3000*((ADC_Sum/ADC_Count)/1024.0));

         }

        if(ADC_Count>=10)

        {                

            Battery_Value=(int)(3000*((ADC_Sum/ADC_Count)/1024.0));

            ADC_Count=0;ADC_Sum=0;

             Serial.print("Voltage: ");

           Serial.print(Battery_Value);

           Serial.println(" mV");

        } 

}

Video :https://youtu.be/IM4Vm5CDVmg