Arduino while loop with or condition

Question

How do I write a program to wait (delay) until one out of two buttons pressed? I have written a program to wait until a single button is pressed. It's working fine. However, if I extend it to second button it's not working. Pls help on this.

1. while (digitalRead(bt_Select) == HIGH) {} -- working.
2. while (digitalRead(bt_Select) == HIGH || digitalRead(bt_Reject) == HIGH) {} -- Not working.

Complete code:

const int bt_Select = 2;
const int bt_Reject = 3;
void setup() {
 Serial.begin(9600); 
 pinMode(bt_Select, INPUT_PULLUP);
 pinMode(bt_Reject, INPUT_PULLUP);
}
void loop() {
 Serial.println("Pl input:");
 while (digitalRead(bt_Select) == HIGH {} // This is the line I change
 
 if (digitalRead(bt_Select) == LOW) {
 Serial.println("Select Button pressed:");
 delay(250);
 Serial.println("");
 }
 if (digitalRead(bt_Reject) == LOW) {
 Serial.println("Reject Button pressed:");
 delay(250);
 Serial.println("");
 }
}

Answer 1

while (digitalRead(bt_Select)==HIGH||digitalRead(bt_Reject)==HIGH){}

should be

while (digitalRead(bt_Select)==HIGH&&digitalRead(bt_Reject)==HIGH){}

The first loop would break only if you press both buttons at once. I believe you are trying to break if either button is pressed.

• Ak Rikas: yes I try to break if either button is pressed.
• Ak Rikas: Thank you it's working.. 5n
• Ak Rikas: however i confused how it could works?!*
• Python Schlange: @AkRikas Your code stays in the while loop when one of the buttons is HIGH and the other code when both are HIGH. Does this answer your question?
• Delta_G: @Ak Rikas - The condition in the while loop is a continue condition, not a break condition. You want the loop to break when one OR the other is pressed. That means it should continue when both are not pressed. In order to test that both are not pressed you need to use AND.