shiftregister debouncing

Using Arduino Project Guidance
1

Hello ... i am working on project involving a reaction time game, where i have 52 illuminated led push buttons, the play should hit the button as soon as it lids.

I am using a series of 74hc165 and 74hc595 chained together and connected to an arduino.

This my code :

#define NUMBER_OF_SHIFT_CHIPS   7
#define DATA_WIDTH   NUMBER_OF_SHIFT_CHIPS * 8

const int DataPin= 11; // Connect Pin 11 to SER_OUT (Serial data out) - Pin 9 (Q7) of 74HC165
const int LoadPin = 8; // Connect Pin 8 to SH/!LD (shift or active low load) - Pin 1 (!PL) of 74HC165
const int ClockPin= 12; // Connect Pin 12 to CLK (the clock that times the shifting) - Pin 2 (CP) of 74HC165
const int EnablePin = 9; // Connect Pin 9 to !CE (clock enable, active low) - Pin 15 (!CE) of 74HC165


unsigned char Total_Switch[57] = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57};

#define T_Poll 250 // register polling period (ms)
unsigned long oldtime;


unsigned int i;

unsigned char Switch_number = 0;
unsigned char old_Switch_number = 0;

void setup()
{
  Serial.begin(9600);
  pinMode(LoadPin, OUTPUT);
  pinMode(ClockPin, OUTPUT);
  pinMode(EnablePin, OUTPUT);
  pinMode(DataPin, INPUT);


  
  digitalWrite(ClockPin, LOW);
  digitalWrite(LoadPin, HIGH);

  oldtime = millis();

}

void loop()
{
   buttonWait();
}

void buttonWait(){
  if (millis() - oldtime > T_Poll) {
  while(1){
    
    Switch_number = read_shift_regs();
      if ((Switch_number != old_Switch_number)) {
        Serial.println(Switch_number);
        old_Switch_number = Switch_number;
        return;
      }
         

    }
    oldtime = millis();
  }
}


unsigned char read_shift_regs()
{

     Switch_number = 0;
     
     // Enable the register!
     digitalWrite(EnablePin,HIGH);
     digitalWrite(LoadPin, LOW);
     delayMicroseconds(5);
     digitalWrite(LoadPin,HIGH);
     digitalWrite(EnablePin,LOW);
     
     // Read the bits on the register and store in var 
     for (i = 0; i < 57; i++)
     {
       if (digitalRead(DataPin) == HIGH){
       
              Switch_number += Total_Switch[i] ; 
       }
      
       digitalWrite(ClockPin,HIGH);
       delayMicroseconds(5);
       digitalWrite(ClockPin,LOW); 
    }
    

  return Switch_number; 
}

i am still working only on the "switch part" of the code.

i am trying to resolving debouncing problem, but i am not sure it is working, because i am getting, lets say i click button 128 and then 3 and then 10 :

128
0
3
0
10
0

is it enough to use

    Switch_number = read_shift_regs();
      if ((Switch_number != old_Switch_number) && Switch_number != 0) {
        Serial.println(Switch_number);
        old_Switch_number = Switch_number;
        return;
      }

to keep it from sending dobble value ? .. thank you

2

I Think there is a deouncy library used by an other member ia a question not long ago. Make a search!

3

i already made my research, and there are alot of debouncing libraries, i wasn't sure which one to choose, that's why i wanted to write my own code. bur i am a beginner, so that's why i am asking for help.

4

That's understandable. Debouncing buttons was among the first exercises in Mikroprocessor theory some 1975.
Upon the first flank You check the button x milliseconds later to verify it's still active. Check Your buttons for the time length of their bouncing. Adding a few ms to that gives You the x.

5

i Understand, that's what exactly what i am trying to do :

void buttonWait(){
  if (millis() - oldtime > T_Poll) {
  while(1){
   
    Switch_number = read_shift_regs();
      if ((Switch_number != old_Switch_number)) {
        Serial.println(Switch_number);
        old_Switch_number = Switch_number;
        return;
      }
         

    }
    oldtime = millis();
  }
}

i just cannot get it to work, and i am not sure what i am doing wrong

6