How to compare string from Serial.read()?

Question

I have this code below where I got from this forum that I followed through. It did not work for me but they claim that the code is fine. I already tried several string compariso

Answer 1

Why not use Serial.readString();??

Try this..

     void setup() {
      pinMode(13, OUTPUT);
      Serial.begin(9600);
    }

    void loop(){
      if(Serial.available()){
        String ch;
        ch = Serial.readString();
        ch.trim();
        if(ch=="on"||ch=="ON"){
          digitalWrite(13, HIGH);  
        }
        else if(ch=="off"||ch=="OFF"){
          digitalWrite(13, LOW);
        }
      }
    }