Receiving serial data as string and comparing them with other strings

Projects Interfacing w/ Software on the Computer
3

Hello Graynomad, thanks for your help :slight_smile:
I have changed my program as you suggested. I have included a null terminator and used strcmp but still the output is same :frowning:
Do you see any logical error in my code?

int ledPin = 13;           
const int maxLength=140;        //maximum length for textbox data
char char_in[maxLength];  //Create a buffer to input all incoming data
int i=0;
void setup() {

  pinMode(ledPin, OUTPUT);  //Configure pins as output

  Serial.begin(9600);      //begin serial communication

}


void loop() {

  if (Serial.available() > 0)     //Is any serial data available
  {


    for( i=0;i<maxLength && Serial.available();i++)
    {
      char_in[i] = Serial.read();
    
    }
  
   char_in[i+1]='\0';
    if (!strcmp(char_in,"on1"))
    {
      digitalWrite(ledPin,HIGH);
    }
    else if(!strcmp(char_in,"of1"))
    {
      digitalWrite(ledPin,LOW);
    }
    else 
    {
      Serial.print(char_in); 

    }

  }
  


}