====== Using the Python API on Linux ======


====== Introduction ======

Pixy now has a Python wrapper for libpixyusb. For now, this is only available for Linux-based controllers (e.g. Raspberry Pi, BeagleBone). The [[wiki:v1:Building_the_libpixyusb_example_on_Linux|libpixyusb]] library provides a software application programming interface (API) for communicating with Pixy over USB. The following procedure will outline the steps to build libpixyusb as a Python module.

This procedure assumes the following:

  * Your system is Linux (with Debian package manager)
  * Pixy firmware has been updated to 1.0.2 or higher
  * Your system is connected to the internet (for getting packages)

Instructions for updating the Pixy firmware are here: [[wiki:v1:Uploading_New_Firmware|Uploading New Firmware]]


====== 2. Procedure ======


===== 2.1. Install dependencies for building Python SWIG module =====

Start a terminal application.


==== 2.1.1. Install SWIG ====

In a terminal window type:

''%%# sudo apt-get install swig%%''


==== 2.1.2. Install libusb-1.0-0-dev ====

In the terminal window type:

''%%sudo apt-get install libusb-1.0-0-dev%%''


==== 2.1.3. Install g++ (compiler) ====

In the terminal window type:

''%%sudo apt-get install g++%%''


==== 2.1.4. Install libboost ====

In the terminal window type:

''%%sudo apt-get install libboost-all-dev%%''


===== 2.2. Build the libpixyusb Python module =====


==== 2.2.1 Download Pixy source code ====

In the terminal window type:

''%%git clone https://github.com/charmedlabs/pixy.git%%''


==== 2.2.2. Build the Python module ====

In the terminal window type:

''%%cd pixy/scripts%%''\\
''%%./build_libpixyusb_swig.sh%%''


===== 2.3. Try it out! =====

Make sure your Pixy is connected to a USB port on your computer. Then in the terminal window type:

''%%cd ../build/libpixyusb_swig%%''\\
''%%python get_blocks.py%%''

If all goes well, you should see blocks:

''%%Pixy Python SWIG Example -- Get Blocks%%''\\
''%%[BLOCK_TYPE=0 SIG=1 X=220 Y= 17 WIDTH= 43 HEIGHT= 35]%%''\\
''%%[BLOCK_TYPE=0 SIG=1 X=220 Y= 23 WIDTH= 42 HEIGHT= 47]%%''\\
''%%[BLOCK_TYPE=0 SIG=1 X=220 Y= 23 WIDTH= 42 HEIGHT= 47]%%''\\
''%%[BLOCK_TYPE=0 SIG=1 X=220 Y= 23 WIDTH= 42 HEIGHT= 47]%%''\\
''%%[BLOCK_TYPE=0 SIG=1 X=220 Y= 23 WIDTH= 42 HEIGHT= 46]%%''\\
''%%[BLOCK_TYPE=0 SIG=1 X=220 Y= 23 WIDTH= 45 HEIGHT= 46]%%''\\
''%%[BLOCK_TYPE=0 SIG=1 X=219 Y= 23 WIDTH= 43 HEIGHT= 46]%%''

If you don't see any block information, try running as superuser:

''%%sudo python get_blocks.py%%''