从模拟引脚获取电压

模拟引脚可用于读取电压，这对电池监控或与模拟设备接口非常有用。默认情况下，AREF 引脚与 arduino 的工作电压相同，但可以在外部设置为其他值。如果要读取的电压大于输入电压，则需要潜在的分压器来降低模拟电压。

#define analogPin 14    //A0 (uno)
#define AREFValue 5        //Standard for 5V Arduinos
#define ADCResolution 1023    //Standard for a 10bit ADC

int ADCValue = 0;
float voltage = 0;

void setup()
{
    Serial.begin(9600);
}

void loop() 
{
    readADC();
    Serial.print(voltage); Serial.println("V");
}

void readADC()
{
    ADCValue = analogRead(analogPin);
    float = ( ( (float)ADCValue/ADCRange ) * AREFValue );    //Convert the ADC value to a float, devide by the ADC resolution and multiply by the AREF voltage
}