#define grinderRelay        3
#define acs712              A0
#define grinderDirPositive  8
#define grinderStepPositive 4

const unsigned int stepTime = 3; // interval for stepping using millis

// unsigned long previousTime1 = 0;
// unsigned long previousTime2 = 0;
// unsigned long startTime = 0;
// unsigned long currentTime = 0;
unsigned long  grinderMotorOnTime = 1000;
bool grinderRunFlag = false;

int16_t offset;
const float maxCurrent = .1;
float current;

void setup() {
  Serial.begin(115200);
  pinMode(acs712, INPUT);
  pinMode(grinderRelay, OUTPUT);
  pinMode(grinderStepPositive, OUTPUT);
  pinMode(grinderDirPositive, OUTPUT);
  digitalWrite(grinderRelay, LOW); // Disable grinder motor via relay
  Serial.println();
  Serial.println("Starting...");

  Serial.println("Calibrating ACS712 :");
  offset = analogRead(acs712);
  Serial.print("0 - Reading ");
  Serial.println(offset);
  int16_t measureMin = offset;
  int16_t measureMax = offset;
  for(uint8_t measureIndex = 1; measureIndex < 10; measureIndex++)
  {
    int16_t measure = analogRead(acs712);
    measureMin = min(measure, measureMin);
    measureMax = max(measure, measureMax);
    offset += measure;
    Serial.print(measureIndex);
    Serial.print(" - Reading ");
    Serial.println(measure);
    delay(100);
  }
  offset /= 10;
  Serial.print("Offset: ");
  Serial.print(offset);
  Serial.print("  Min:");
  Serial.print(measureMin);
  Serial.print("  Max: ");
  Serial.println(measureMax);
  delay(2000); // 2 seconds to read the Offset

  digitalWrite(grinderRelay, HIGH); // enable grinder motor via relay
  digitalWrite(grinderDirPositive, HIGH);    // Direction counter clockwise
}

void checkCurrent() {
  current = float(analogRead(acs712) - offset)  / 27.027; //gives Ampere
  Serial.println(current,2);
}

void loop() {
  // Run Grinder forward for a bit
  checkCurrent();

  while (abs(current) <= maxCurrent) {
    digitalWrite(grinderStepPositive, LOW); 
    delay ( stepTime); 
    digitalWrite(grinderStepPositive, HIGH);
    delay ( stepTime);
    // checkCurrent();
  }
}