#include<Ticker.h>
#include <Wire.h>
#include "Adafruit_MCP23017.h"
int AC_pin_mcp = 7;
Ticker tick;
int dim = 0; //Initial brightness level from 0 to 255, change as you like!
Adafruit_MCP23017 mcp;
void setup() {
  mcp.begin();      // use default address 0
  mcp.pinMode(AC_pin_mcp, OUTPUT);
  Serial.begin(115200);
  pinMode(12, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(12), light, FALLING); //When arduino Pin 2 is FALLING from HIGH to LOW, run light procedure!
}
volatile int it = 0;
volatile int lzc = 0;
volatile int zc = 0;

void light() {
 // noInterrupts();
  tick.attach_us(990, set);
  it = 0;
  zc = millis() - lzc;
 // Serial.println("zc: " + String(zc));
  lzc = (int)millis();
 // interrupts();
  }

void set() {
   //int enter = (int)millis();
   Serial.println(it);// + " -- " + String(dim) + " -- " + millis());
    if (it == dim)  {
   // Serial.println("match");
    if (it < 1) {
      mcp.digitalWrite(AC_pin_mcp, HIGH);
    }
    else if (it > 9) { 
      mcp.digitalWrite(AC_pin_mcp, LOW);
    }
    else if (it >= 1 && it <= 9 ) {
      mcp.digitalWrite(AC_pin_mcp, HIGH);
      delayMicroseconds(10);
      mcp.digitalWrite(AC_pin_mcp, LOW);
    }
  
  it++;
  }
 it++;
// int time_=millis()-enter;
  //Serial.println("loop millis : " + String(time_));
 }

void loop() {
  String input = "";
  while (Serial.available()) {
    input += (char)Serial.read();
  }
  if (input != "" )
  {
         dim = input.toInt();
  }
  //Serial.println("Dim:" + String(dim));
  delay(500);
}