Using Python to control blink(1)

There are three ways to get Python to access blink(1):

• Use the PyUSB library to construct USB HID requests
• Wrap the "blink1-lib" C-library located in blink1/commandline
• Wrap the "blink1-tool" command line executable

There are pros and cons ot each technique.

PyUSB method

Pros:

• 100% Python, no native C-code dependencies; if you have PyUSB, this will work
• Effeciently uses system resources (assuming PyUSB does)

Cons:

• Requires user to install PyUSB (which usually requires admin access)
• PyUSB not available on all platforms
• Requires re-implementing functions in blink1-lib or blink1-tool

blink1-lib wrapper method

Pros:

• No extra libraries to install
• Functionality matches blink1-lib by definition

Cons:

• Native C-code code makes it harder to port to other systems

blink1-tool commandline wrapper

Pros:

• 100% Python
• Easy to understand
• Usable on many more platforms like Raspberry Pi

Cons:

• Ineffecient; Spawns a process for each blink(1) call
• Requires user to have blink1-tool downloaded and in path

Python libraries

Thanks to members of the blink(1) community, we have working examples of all three techniques:

• "blink1hid-demo.py" - Aaron Blondeau's script uses PyUSB to show how to construct raw HID reports that send commands to blink(1)

• "blink1-ctypes.py" - Stephen Youndt's script shows how to wrap the C library

• "bliPi.py" - DPontes wrapper of blink1-tool, available at : https://github.com/DPontes/bliPy/blob/master/bliPy.py