This little tutorial explains on how you can modify the default spray script in the iMatrixSpray. Please be careful when doing so and make backups for all files before you modify them. If the iMatrixSpray should be rendered inoperable, you may download the original image (1.2 GB), unzip it and flash it to the SD card using WinDiskImager. So there is no risk of permanent damage…

Download the software WinSCP from https://winscp.net to the same computer where you are connected to the iMatrixSpray.
The software does not need installation, just execute WinSCP.exe

Connect to the iMatrixSpray entering the address of the device, e.g. 10.10.10.10 when connected by WLAN. Username is “pi” and password is “raspberry”
Once connected, navigate to the directory /home/pi/OctoPrint/octoprint/
In there you’ll find a file “server.py”. Make a local backup copy and then edit the source on the server. Search for the lines
sp_x1 = -60.0
sp_x2 = 60.0
sp_y1 = -80.0
sp_y2 = 80.0

and modify them to your needs. Once satisfied, safe the file. Now we need to activate it by restarting the webserver. This is done in WinSCP, opening the Terminal with “Ctrl-T”. When the terminal windows pops up, enter “/home/pi/opr” in the command field and press “Execute”. Wait a few seconds and connect again to the iMatrixSpray web interface.

There is more… For example you may modify the user interface to add buttons and input fields for your specific tasks. Check out the documentation on the web on “OctoPrint” or engage in a discussion on this forum.

Another simple but powerful way for customization is to use the server.py code and modify it to run locally on your computer. Using this method, you can very simple generate custom .gcode files which you can upload to the iMatrixSpray and execute them with a simple click.