//
// samd11c14a_hallsensor.ino
//
// SAMD11C and HALL SOT23 Sensor
//
// Joanne Leong
//
// This work may be reproduced, modified, distributed,
// performed, and displayed for any purpose. Copyright is
// retained and must be preserved. The work is provided
// as is; no warranty is provided, and users accept all 
// liability.

//Joanne's Board Details 
const int SENSOR_PIN = 14; //PA04 --> external hall sensor board
const int LED = 5; //PA05 --> integrated led

//Sensor variables
int raw_val = 0;
int smoothed_val=0; //Store analog and digital values
bool is_tared = false;
int offset = 0; //how much to offset raw sensor signal after tare

//Smoothing
const int numReadings = 10; 
int readings[numReadings]; //readings from the analog input
int readIndex = 0; //index of hte current reading
int total = 0; // running total
int average = 0; // the average

void setup() {
  pinMode(LED, OUTPUT); //initialize the LED pins as outputs: 
  pinMode(SENSOR_PIN, INPUT); //initialize the analog pin as input: 

  //initialize serial communication with the computer
  Serial.begin(9600);

  //initialize all the readings to 0
  for (int thisReading = 0; thisReading < numReadings; thisReading++){
    readings[thisReading] = 0;  
  }
}

void loop() {
  raw_val = analogRead(SENSOR_PIN);
  smoothed_val = smoothing(tare(raw_val));
  if(smoothed_val > -3 && smoothed_val< 3){smoothed_val = 0;} //filter out fine noise
  Serial.println(smoothed_val);

  //make led light up if field value is large enough
  if(abs(smoothed_val) > 50){
    digitalWrite(LED,HIGH);
  }else{
    digitalWrite(LED,LOW);
  }
}


int tare(int val){
  if(!is_tared){
    offset = val;
    is_tared = true;
  }
  return val-offset;
}

int smoothing(int val){
  total = total - readings[readIndex]; //subtract the last reading
  readings[readIndex] = val;
  total = total + readings[readIndex]; // add the reading to the total 
  readIndex = readIndex + 1; //advance to the next position in the array

  if (readIndex >= numReadings){ //reset index when it exceeds number of readings
    readIndex =0;
  }

  average = total / numReadings; //calculate the average
  delay(1);
  return average;
}

//void blink(){
//  Serial.println("LED ON");
//  digitalWrite(Integrated_Led,HIGH);
//  delay(1000);
//  digitalWrite(Integrated_Led,LOW);
//  delay(1000);
//}