#include <Keypad.h>

const uint8_t ROWS = 4;
const uint8_t COLS = 4;
char keys[ROWS][COLS] = {
  { '1', '2', '3', 'A' },
  { '4', '5', '6', 'B' },
  { '7', '8', '9', 'C' },
  { '*', '0', '#', 'D' }
};

uint8_t colPins[COLS] = { 5, 4, 3, 2 }; // Pins connected to C1, C2, C3, C4
uint8_t rowPins[ROWS] = { 9, 8, 7, 6 }; // Pins connected to R1, R2, R3, R4

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// start of relay settings
const int relayPin[]={A4,A2,A1,A0};// output pins where 8 relays will be connected
String relayNames[] ={"CH1", "CH2","CH3","CH4"};// Just put name for 8 relays
// do not change lines bellow
int pushed[] ={0,0,0,0};// status of each buttons
int relayStatus[] ={LOW,LOW,LOW,LOW};// initial status of relay

// led part
#define led 10

void setup() {
  Serial.begin(9600);

  for(int i=0; i<8; i++)
  {
    pinMode(relayPin[i], OUTPUT); // set relay pins as output  
    digitalWrite(relayPin[i], LOW);// initial relay status to be OFF
  }

  pinMode(led,OUTPUT);
}

void loop() {

  digitalWrite(led,HIGH);
  
  

  controleKeypad();
}

  void controleKeypad(){
  int val;
  int knum;
  char key = keypad.getKey();
  
    // just print the pressed key
  if(key && key !='*' && key !='#' && key !='0' && key !='9' ){
    knum = (int)key-49;// convert char to integer (one less)
    if(knum>=0 && knum<8){
     Serial.println(knum);
         if(relayStatus[knum] == LOW){
        
            pushed[knum] = 1-pushed[knum];
            delay(50);
          }// if   
         controlRelay(knum);// turn relay ON or OFF
    }
    
  }else{
    val = LOW;
  }
  
  if(knum>=0 && knum<8){
        relayStatus[knum] = val;
  }

delay(50);

}// loop end



 

 void controlRelay(int number)
 {

     if(pushed[number] == 1)
     {
      digitalWrite(relayPin[number], HIGH);// Turn ON relay
      Serial.print(relayNames[number]);
      Serial.println(" ON");
      delay(2000);
      digitalWrite(relayPin[number], LOW); // turn OFF
      Serial.print(relayNames[number]);
      Serial.println(" OFF");
     }

}