using Raspberry Pi to control Arduino using pyFirmata

Setting up your Arduino for Firmata

Firmata control of the Arduino requires loading an Arduino with the special Firmata sketch. You can download the Arduino software from the Arduino website. After opening the Arduino IDE, follow these steps to install Firmata on your Arduino:

1. Click File->Examples->Firmata->StandardFirmata
2. From the Tools->Board menu, select the type of Arduino you are using.
3. From the Tools->Serial Port menu, choose the USB port to which your Arduino is connected.
4. Click the upload button (it looks like a right arrow, just next to the checkmark) and wait for your sketch to upload. A message in the bottom black windowwill indicate success or failure
5. Once the Firmata sketch is loaded on your Arduino, you can test it out with the Firmata Test Program.

Controlling your Arduino from Python

Next, your Raspberry Pi must be setup with the python firmata libraries. Run the following commands:

  sudo apt-get install python-pip python-serial
  sudo pip install pyfirmata

Use a USB cable to connect the Arduino with the Raspberry Pi (remember to use the big USB Standard A connector and not the smaller Micro B power connector). You can now find the USB name of the Arduino by running 'ls -lrt /dev/tty*'. On my Raspberry Pi, it was listed as /dev/ttyUSB0. Remember this value for later.

Connecting to an Arduino

To control an Arduino from a Python script on your Raspberry Pi, you must first import the Arduino and util classes from the pyfirmata module. Then, create an object using the USB address you found in the previous step

 sudo python

  >>> from pyfirmata import Arduino, util
  >>> board = Arduino('/dev/ttyUSB0')

proceed to  pyfirmata github for further introductions