How to make Arduino to read 1X4 keypad multiple times?

Question

I want to use 1X4 membrane keypad to enter 3 working parameters for LED string controlled by Arduino mini. Keypad is attached to D2-D5 pins and LED is attached to pin 12. My objective is to set the following parameters: frequency (4 values), duty cycle (4 values), run time 4 (values). I need Arduino to read keypad 3 times so I can enter 3 parameters. "Run time" In the sketch below has not been set. I want to use "while" to force Arduino to read the keys but arduino reads it once. Only first "while" is working in the code and I can set cycle period. Second "while" does not work because the key has been already pressed and Arduino does not read keypad second time. Are there any means to use more than 1 "while" in the code or to use one while to read keypad 3 times?

Thank you.

 #define Key1 3 // key 1 attached to pin 3
 #define Key2 2 // key 2 attached to pin 2
 #define Key3 5 // key 3 attached to pin 5
 #define Key4 4 // key 4 attached to pin 4
 float period; // cycle time
 float power; // duty cycle
 float ontime; // ontime time LED is on
 float rest; // rest time LED is off
 const int ledPin = 12; // the number of the LED pin
 
 void setup()
 {
 pinMode(Key1, INPUT_PULLUP);
 pinMode(Key2, INPUT_PULLUP);
 pinMode(Key3, INPUT_PULLUP);
 pinMode(Key4, INPUT_PULLUP);
 pinMode(ledPin, OUTPUT);
 }
 void loop() {
 digitalWrite(ledPin, LOW);
 while (digitalRead(Key1) == HIGH && digitalRead(Key2) == HIGH && digitalRead(Key3) == HIGH && digitalRead(Key4) == HIGH) {};
 
 int key1a = digitalRead(Key1);
 int key2a = digitalRead(Key2);
 int key3a = digitalRead(Key3);
 int key4a = digitalRead(Key4);
 
 if (!key1a) {
 period = 1000;
 }
 if (!key2a) {
 period = 2000;
 }
 if (!key3a) {
 period = 3000;
 }
 if (!key4a) {
 period = 4000;
 }
 
 while (digitalRead(Key1) == HIGH && digitalRead(Key2) == HIGH && digitalRead(Key3) == HIGH && digitalRead(Key4) == HIGH) {};
 
 int key1b = digitalRead(Key1);
 int key2b = digitalRead(Key2);
 int key3b = digitalRead(Key3);
 int key4b = digitalRead(Key4 );
 
 if (!key1b) {
 power = 10;
 }
 if (!key2b) {
 power = 20;
 }
 if (!key3b) {
 power = 50;
 }
 if (!key4b) {
 power = 80;
 }
 
 ontime = period * power / 100;
 rest = period - ontime;
 
 digitalWrite(ledPin, HIGH);
 delay(ontime);
 digitalWrite(ledPin, LOW);
 delay(rest);
 }

• jsotola: I want to use "while" ... why? ... what if it makes no sense to use "while"?
• alex 001: What makes sense?
• jsotola: it would make more sense to detect a button press at begining of loop() and set a variable to 0, 1, 2, 3 or 4 ... 0 = no button ... use a state variable to keep track of which parameter you are changing

Answer 1

Do something to wait until a key is released before advancing to the next section. It would be wise to structure your program to have only one function that processes key presses, and then call it for each key. (Pass key identification, pin number, into the function.)