Clearing Arduino's serial buffer

Question

i have a simple arduino code:

void loop()
{
  if serial.available
  {
    c = serial.read();
    if (c == 'a')
    {
      blinkled();
    }
    else
      offled();
  }
}

it should glow the led if i send a character 'a'. and it shld go off when i dont give anything when the loop goes into the next itration.

but once i give 'a'. it starts glowing and never goes off.

is it reading the char 'a' from the buffer? if so then how to clear it ?

Serial.flush() not working.

any ideas please. am new to arduino. sorry if its silly.

Answer 1

You have put your offled function INSIDE the Serial.available() path. You could only turn it off by Serial.available() being true and you pushing a different character so it reads something other than 'a'

Unfortunately the example above makes the same mistake.

Construct it so that the led turns off outside that if statement

Answer 2

You could use something like this:

void loop() {
    while (Serial.available() > 0)
    {
        char received = Serial.read();
        inData += received; 

        // Process message when new line character is received
        if (received == '\n')
        {
            Serial.print("Arduino Received: ");
            Serial.print(inData);

            // You can put some if and else here to process the message juste like that:

            if(inData == "a\n"){ // DON'T forget to add "\n" at the end of the string.
              Serial.println("OK, I'll blink now.");
              blinkled();
            }
            else if (inData == "b\n") {
              offled();
            }   

            inData = ""; // to flush the value.
        }
    }
}

EDIT : I've modified my answer based on the correct answer.

Answer 3

This could be a solution:

void loop()
{
    offled();    
    char c = Serial.read();
    while (Serial.available() <= 0 || c != 'a') { 
        blinkled();      
    }
}