arduino_control

This is a very specific application designed to control an EWOD experiment using an Arduino from a web interface.

Dependencies

The app works under Ubuntu 15.04 and Windows 8, 10 (older versions probably too). The following packages must be present in the python installation to make it work:

• pyserial
• pyfirmata
• cherrypy
• mako
• numpy
• scipy
• scikit-image
• matplotlib

Additionally, the camera addon uses the program CommandCam.exe, developed by Ted Burke and available at github. For convenience however, the executable is included in the camera addon folder of the repository.

Running

On Windows, where the Arduino is usually on the COM3 port:

python app.py

On Ubuntu, running with privileges is necessary to be able to connect to the serial device. On my machine, the Arduino is on /dev/ttyACM0:

sudo python3 app.py

For more options add the --help argument, e.g. python3 app.py --help.

Custom scripts

Scripts are intended to be used for simple repetitive tasks, for more elaborate extensions see Addons.

Writing a custom script

Custom scripts are subclasses of the Script class from the app_script module. They must implement the run function at least, and they should use the convenience method serial_write to send commands to the Arduino. They must be stored in the scripts folder. For an example, see script_test.py.

Running a script

To run a script either use the web interface or make a request to /serialScript with the name of the script and the kwargs as json payload. For example:

requests.post('http://localhost:8080/serialScript',
  data={'fname':'script_test','string':'Hello world!'})

Available commands

The following commands can be sent to the Arduino using the aforementioned convenience method. Use this list as a reference of the parameters for each command. For more information on the method's signature, see the docstrings.

• vset [pins:(3,9,10,11)] [values:(0-255)] settling:(0:inf)

• vread [pins:(0,1,2,3,4,5)]

Addons

These provide more flexibility than a script at the cost of more writing. They are basically composed of a python module that is attached to the server, and an html ui with its js scripts and other resources. The folder structure to use is similar to the camera addon, so check that one for reference.

Console mode

Sometimes the web interface might not be very convenient, especially when experimenting with new things. In these cases, the serial_controller file in the modules folder is still very easy to use and effective in controlling the Arduino manually. The file experiments_convenience_functions.py has some extra helper functions.