Power Meter

#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>
#include <WiFiClient.h>

const char* ssid = "";
const char* password = "";


unsigned long lastPulse = 0;
unsigned long between;
unsigned long lastSend = 0;


float power;
String str = "";
unsigned long cmillis;



String url = "http://*******/powerinput";
int httpResponseCode;

struct tpulse {
  float power;
  unsigned long ms;
};

tpulse pulses[20];
uint8_t pulsesinarr = 0;



void ICACHE_RAM_ATTR pulse() {

  cmillis = millis();
  if (lastPulse == 0) {  //Skipping the first reading
    lastPulse = cmillis;
    return;
  }
  between = cmillis - lastPulse;

  if (between > 70) {

    lastPulse = cmillis;
    power = (1000.0 * 60.0 * 60.0 / (between));
    Serial.print(power);
    Serial.print(" ");

    tpulse p;
    p.power = power;
    p.ms = cmillis;
    if (pulsesinarr < 20) {
      pulses[pulsesinarr] = p;
      pulsesinarr++;
    }

  }

}





void sendData() {
  Serial.println("senddata");
  if (WiFi.status() == WL_CONNECTED) {
    Serial.print("wifi status: ");
    Serial.println(WiFi.status());
    WiFiClient client;
    HTTPClient http;


    http.begin(client, url);

    http.setTimeout(1500);
    http.addHeader("Content-Type", "application/json");

    http.addHeader("memsize", String(ESP.getFreeHeap()));


    String output = "[";

    for (int i = 0; i < pulsesinarr; i++) {
      output += "[";
      output += String(pulses[i].power);
      output += ", " + String(pulses[i].ms);
      output += "]";
      if (i < (pulsesinarr - 1)) output += ", ";
    }

    output += "]";
    Serial.println(output);
    pulsesinarr = 0;
    lastSend = millis();


    Serial.println(httpResponseCode);
    http.end();

  } else {
    Serial.println(WiFi.status());
  }
}



void setup() {
  Serial.begin(115200);

  pinMode(D5, INPUT);

  attachInterrupt(digitalPinToInterrupt(D5), pulse, FALLING);

  // Connect to Wi-Fi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi..");
  }

  // Print ESP Local IP Address
  Serial.println(WiFi.localIP());
}


void loop() {

  if (pulsesinarr > 0 && (millis() - lastSend) > 1700) sendData();

  delay(500);
}