title: How to convert a char to int in Arduino
body: <p>I receive some data in a char variable, and the result in teststring is always a number. How can I convert this number to a variable int?</p>
  
  <p>After that I can put the int variable on delay time. There is a piece of my code:</p>
  
  <pre><code>String readString = String(30);
  String teststring = String(100);
  int convertedstring;
  
  teststring = readString.substring(14, 18); (Result is 1000)
  
  digitalWrite(start_pin, HIGH);
  delay(convertedstring); // Result of teststring convert
  digitalWrite(start_pin, LOW);
  </code></pre>