Controlling Robot with Cell Phone. Part One

This tutorial, we will show how to use Strings with the Arduino. A String is a char array terminated by the null char (0x00, or ). You can define a String as a char array and can use many functions straight on it. The string library define a class, that can also be used for comparing 2 strings,

like this example:String sentence = "Hello World"; String str;char c; char matrix[20]; int x=0; void setup(){     Serial.begin(9600); } void loop(){     if(Serial.available()){       do{        c=Serial.read();        matrix[x]=c;        Serial.print(matrix[x],DEC);        x++;        delay(1); //some delay      }while(c!=' ');         matrix[x-1]='';         Serial.print(matrix);         str=matrix;         if (str==sentence){            Serial.println("OK");         } else {            Serial.println("Error");         }      } } On this sample, we defined a temporary array to store the characters before sending it to a string variable (str). Then, we could compare it with our desired sentence (Hello Word) using the = sign. Also, this program outputs the ascii values before sending back the received data:

Source    Garagelab