Create README.md

Updated readme

Author: marabesi

README.md

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+# arduino-php-wrapper
+
+If you are wondering how to control the Arduino serial port via PHP, here is the solution. 
+The **arduino://** wrapper is a easy and straightforward way to write and read data from Arduino.
+
+## Usage
+
+to write date on Arduino serial just use the regular I/O functions in PHP such as **fwrite** or file_put_contents**
+
+``` php
+//reads data from Arduino
+$resource = fopen('arduino://ttyUSB0', 'r+');
+print fread($resource, 1024); 
+```
+
+Or if you prefer, you can use **file_get_contents** and get the same result
+``` php
+print file_get_contents('arduinno://ttyUSB0');
+```
+
+To write data in the Arduino serial is as easy as it could be
+
+``` php
+//writes data to Arduino
+$resource = fopen('arduino://ttyUSB0', 'r+');
+print fwrite('hello Arduino'); 
+```
+
+``` php
+print file_put_contents('hello Arduino');
+```
+
+## Improvements
+
+As you can see is really simple and we can improve it much more as the sensors are identified