/*
ACS714 sur Arduino Uno
*/

#define RefVal 5.0
#define Pin A0

// Take the average of 500 times
const int averageValue = 500;
long int sensorValue = 0;
float sensitivity = 1000.0 / 185.0;  //1000mA per 185mV

// Output voltage with no current: 2500mV
float Vref = 2500;

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

void loop() {
  // Read the value 500 times:
  for (int i = 0; i < averageValue; i++) {
    sensorValue += analogRead(Pin);

    // wait 2 milliseconds before the next loop
    delay(2);
  }
  sensorValue = sensorValue / averageValue;

  // The on-board ADC is 10-bits
  // Different power supply will lead to different reference sources
  // example: 2^10 = 1024 -> 5V / 1024 ~= 4.88mV
  //          unitValue= 5.0 / 1024.0*1000 ;
  float unitValue = RefVal / 1024.0 * 1000;
  float voltage = unitValue * sensorValue;

  // When no load,Vref=initialValue
  Serial.print("initialValue: ");
  Serial.print(voltage);
  Serial.println("mV");

  // Calculate the corresponding current
  float current = (voltage - Vref) * sensitivity;

  // Print display current (mA)
  Serial.print(current);
  Serial.println("mA");

  Serial.print("\n");

  // Reset the sensorValue for the next reading
  sensorValue = 0;
  // Read it once per second
  delay(1000);
}