//#include <avr/dtostrf.h>

#define HALL_SIG A3 //singal pin for hall effect
#define TRIG 50
#define HALL_PWR 7 //power pin for hall effect

#define MIN(a,b) (((a)<(b))?(a):(b))
#define MAX(a,b) (((a)>(b))?(a):(b))

#define SAMPLE_TIME 10// number of seconds to measure rain sensor in one sample !!!change this to the number you need!!!

char cedges[8];
float edges = 0;

int16_t mag;
int16_t l_mag = -1;
int8_t rising = -1;

void setup() {
  Serial.begin(9600);
  pinMode(HALL_SIG, INPUT);
  pinMode(HALL_PWR, OUTPUT);
  digitalWrite(HALL_PWR, LOW);
  Serial.flush();
}

void loop() {
  float edges = count_edges(SAMPLE_TIME);
  dtostrf(edges,3,2,cedges);
  Serial.write(cedges);
}



uint32_t count_edges(uint32_t time_s){
  uint32_t time_ms = 1000*time_s;
  uint32_t edge_count = 0;
  uint32_t tik = millis();
  uint32_t sdel = 160;
  //l_mag = -1;
  //rising = -1;
  while(millis()-tik < time_ms){
    digitalWrite(HALL_PWR, HIGH);
    delayMicroseconds(100);
    int16_t mag = analogRead(HALL_SIG);
    digitalWrite(HALL_PWR, LOW);
    edge_count += is_edge(mag);
    //Serial.print(edge_count);
    
    // sdel = MIN(sdel, time_ms - (millis() - tik));
    
    // xdelay(sdel);
  }
  return edge_count;
}

uint8_t is_edge(int16_t mag){
  //Serial.println(mag);
  //Serial.println(l_mag);
  if(l_mag == -1){
    l_mag = mag;
    return 0;
  }else{
    int16_t change = mag - l_mag;
    if((change > 0) == rising){
      l_mag = mag;
      return 0;
    }else{
      if (abs(change) > TRIG){
        l_mag = mag;
        rising = !rising;
        return 1;
      }
    }
  }
  return 0;
}