// with help from https://stackoverflow.com/questions/39232634/how-to-input-a-multi-digit-integer-into-an-arduino-using-a-4x4-keypad

#include <Keypad.h>

const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
byte rowPins[ROWS] = {2, 3, 4, 5}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {6, 7, 8, 9}; //connect to the column pinouts of the keypad
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );

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

  Serial.print("Enter the duration in decimal value: ");
  Serial.println(" ");
  float relay_duration = getKeypadFloat();
  Serial.println(" ");
  Serial.print("The value is ");
  Serial.print(relay_duration );
}

void loop()
{
}//loop

float getKeypadFloat()
{
  int debug = 1;
  float beforeDecimal = 0;                         // the number accumulator
  float afterDecimal = 0;
  byte howManyDecimals = 0;
  float finalValue;
  int keyval;                                     // the key press
  int isNum;
  int isStar;
  int isHash;


  Serial.println("Enter digits,then * as decimal point, then decimals,  and # to end");
  if (debug)Serial.print("So far: ");

  // accumulate the part before the decimal
  do
  {
    keyval = keypad.getKey();                          // input the key
    isNum = (keyval >= '0' && keyval <= '9');         // is it a digit?
    if (isNum)
    {
      if (debug)Serial.print(keyval - '0');
      beforeDecimal = beforeDecimal * 10 + keyval - '0';   // accumulate the input number
    }

    isStar = (keyval == '*');
    if (debug)if (isStar)  Serial.print(".");

  } while (!isStar || !keyval);                          // until a * or while no key pressed

  // accumulate the part after the decimal

  do
  {
    keyval = keypad.getKey();                          // input the key
    isNum = (keyval >= '0' && keyval <= '9');         // is it a digit?
    if (isNum)
    {
      if (debug)Serial.print(keyval - '0');
      afterDecimal = afterDecimal * 10 + keyval - '0';  // accumulate the input number
      howManyDecimals++; // increment for later use
    }

    isHash = (keyval == '#');

  } while (!isHash || !keyval);                       // until # or while no key pressed

  finalValue = beforeDecimal + (afterDecimal / pow(10, howManyDecimals));

  if (debug) Serial.println(" ");
  if (debug)Serial.print("Returning: ");
  if (debug)Serial.println(finalValue, howManyDecimals);

  return finalValue;

}//getKeypadFloat