How to Access Output pins of Arduino using Raspberry pi

Connect the arduino uno board with raspberry pi using usb cable adapter
Plug the arduino uno board with raspberry pi via usb cable adapter
Connect the LED positive with 470 ohm resistor in series with the help of breadboard
Connect the 470 ohm resistor with the arduino uno 13^th pin
Connect the LED negative with arduino uno ground
Open the LxTerminal in raspberry pi and type Sudo arduino to open arduino IDE as root user
Click on File->Examples->Basics->Blink

The following program will appear

Blink

Turns on an LED on for one second, then off for one second, repeatedly.

This example code is in the public domain.

// Pin 13 has an LED connected on most Arduino boards.

// give it a name:

int led = 13;

// the setup routine runs once when you press reset:

void setup() {

// initialize the digital pin as an output.

pinMode(led, OUTPUT);

}

// the loop routine runs over and over again forever:

void loop() {

digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)

delay(1000); // wait for a second

digitalWrite(led, LOW); // turn the LED off by making the voltage LOW

delay(1000); // wait for a second

}

8.Click on the verify icon to compile the program

9.Click on the Upload icon to program the arduino

10.Now you can see the LED is Blinking

Note:

By changing the pin number(0-13) of arduino in above program you can control (0-13) ports of arduino respectively
No need install interfacing software like (pyserial,nanpy) more than once .
Once nanpy,pyserial installed correctly it will communicate arduino automatically