user53689: The doubt was came in mind after seeing Arduino documentation. I have to turn my Arduino uno robot 20 degrees without using encoders. So I surfed on Internet for how can I do that. Interestingly I found the reference available on above link. They are not saying about any specific Arduino board. So I have to know that can I do this stuff on my Arduino uno? Also I have to know is that every Arduino comes with onboard compass?

user27653: No current Arduino board comes with an on-board compass. That function description comes from the documentation for the Arduino Robot, which is a retired product.
There may be other "maker" dev boards, such as the Adafruit Circuit Playground Express which have on-board compass peripherals.

53689: <p>The doubt was came in mind after seeing Arduino <a href="https://www.arduino.cc/en/Reference/RobotTurn" rel="nofollow noreferrer">documentation</a>. I have to turn my Arduino uno robot 20 degrees without using encoders. So I surfed on Internet for how can I do that. Interestingly I found the reference available on above link. They are not saying about any specific Arduino board. So I have to know that can I do this stuff on my Arduino uno? Also I have to know is that every Arduino comes with onboard compass?</p>
 27653: <p>No current Arduino board comes with an on-board compass. That function description comes from the documentation for the <a href="https://www.arduino.cc/en/Guide/Robot" rel="nofollow noreferrer">Arduino Robot</a>, which is a retired product.</p>

<p>There may be other "maker" dev boards, such as the <a href="https://learn.adafruit.com/circuit-playground-express-compass/overview" rel="nofollow noreferrer">Adafruit Circuit Playground Express</a> which have on-board compass peripherals.</p>
