#include <Arduino.h>

#define PIR_PIN 27
#define LED_PIN 2

uint8_t prev = LOW;
uint32_t trials = 0, minD = 0xFFFFFFFFUL, maxD = 0;
uint64_t sumD = 0;

void setup() {
  pinMode(PIR_PIN, INPUT_PULLDOWN);
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);
  Serial.begin(115200);
  delay(250);
  Serial.println("event,trial,detect_to_led_on_us,min_us,max_us,avg_us");
}

void loop() {
  uint8_t s = digitalRead(PIR_PIN);

  if (s == HIGH && prev == LOW) {
    uint32_t t1 = micros();
    digitalWrite(LED_PIN, HIGH);
    uint32_t t2 = micros();
    uint32_t d = t2 - t1;

    trials++;
    if (d < minD) minD = d;
    if (d > maxD) maxD = d;
    sumD += d;
    uint32_t avg = (uint32_t)(sumD / trials);

    Serial.print("ON,");  Serial.print(trials);  Serial.print(",");
    Serial.print(d);      Serial.print(",");
    Serial.print(minD);   Serial.print(",");
    Serial.print(maxD);   Serial.print(",");
    Serial.println(avg);
  }

  if (s == LOW && prev == HIGH) {
    uint32_t t1 = micros();
    digitalWrite(LED_PIN, LOW);
    uint32_t t2 = micros();
    uint32_t dOff = t2 - t1;

    Serial.print("OFF,"); Serial.print(trials); Serial.print(",");
    Serial.print(dOff);   Serial.println(",0,0,0");
  }

  prev = s;
  delay(1);
}