Bluetooth serial- a condition in the condition

Using Arduino Programming Questions
1

hi, I need to make a program where I have buttons in the app on my phone and send them via HC-05 Bluetooth serial to Arduino. In Arduino, I have to make a condition in the condition. Example:

if(Serial.readString()=="Button1")
{
     if(Serial.readString()=="Button3")
     {

     }
      else if(Serial.readString()=="Button4")
     {

     }
}
else if(Serial.readString()=="Button2")
{
     if(Serial.readString()=="Button5")
     {

     }
}
2

It is usual to read the string from Serial into a String, and then compare that repeatedly.

Hard to tell what you want to do, given the lack of comments and a specification.

3

and the problem is that when I load "Button1" and then I want to press "Button3" 3 times in a row, it doesn't go through the first condition if (Serial.readString () == "Button1"), and I want, that it will be staying in (Serial.readString () == "Button1") condition unless I press button 2, the others will not be affected

4

first comment is that you don't want to read many times. Just once because once you've read it, it's gone from the Serial buffer.

String message = Serial.readString();
if (message == "Button1") {

} else if (message == "Button2") {

}

what it seems is that if you get Button1 then the next actions can only be Button3 or Button4

➜ you need some sort of state machine to handle this or your code will very quickly become spaghetti code :slight_smile:

the other thing is that readString() will play tricks on you with timeout etc... I would suggest to study Serial Input Basics to understand how to listen to the Serial port

5

...line endings...

6

that too !

7

here is an example of a small state machine:

enum : byte {waitingForB1orB2, gotB1, gotB2} state = waitingForB1orB2;

String message = "";

bool newMessageAvailable() {
  bool messageReceived = false;
  // ... <=== to write
  return messageReceived;
}

void handleBT() {
  if (newMessageAvailable()) {
    switch (state) {
      case waitingForB1orB2:
        if (message == "B1") {
          state = gotB1;
        } else if (message == "B2") {
          state = gotB2;
        }
        break;
      case gotB1:
        if (message == "B3") {
          // handle sequence B1/B3
        } else if (message == "B4") {
          // handle sequence B1/B4
        }
        state = waitingForB1orB2;
        break;
      case gotB2:
        if (message == "B5") {
          // handle sequence B2/B5
        }
        state = waitingForB1orB2;
        break;
      default: break; // error
    }
  }
}

void setup() {
  Serial.begin(9600);
  message.reserve(20);
}

void loop() {
  handleBT();
}

you "just" have to write the function newMessageAvailable() :slight_smile:

8

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