"Digital graffiti" on https://aligot-death.space, available at https://aligot-death.space/projects/digital-graffiti-en


Digital graffiti

Simulating graffitis on a digital medium using a wiimote

Read it aloud: play pause stop
Me laying on the floor painting on the project, as a reference to a picture from the original project

This project was intended as an upgrade of a project by davejavu1969, which allowed to use a wiimote as a virtual spraying can on a projected screen. We wanted to allow children of a computer-education-oriented association to paint on a wall during an event.

To do so, I upgraded the code to allow for multiple remotes (typically two, but more are possible), support different resolutions because we had various second hand video projectors (including one 1080p), and finally cleaned up the code related to calls to the cwiid library handling wiimote interactions, for easier developement.

The is a relatively old project I've made a while ago. The following instructions are a weird mix of technical and non-tech savvy instructions, for archival purposes.


Button Layout, in french:

button layout for the remote. Text version can be found on the repository


Preparing the Raspberry Pi#

Flash raspbian on a SD card, and then install the following packages to interact with the wiimote(s):

sudo apt install bluetooth python-cwiid


Check that bluetooth and the remotes are working using the following command in a terminal:

hcitool scan

And by then pressing both + and - buttons on a remote. After a few seconds, the command should terminate and display the MAC address of the remote.

Non official remotes may not work

Write down the MAC address, and start over with the second wiimote if you have one.

Installing and preparing the project#

Clone the repo and modify the file digital_graffiti_multi.py by putting the MAC addresses from before between lines 570 and 574


Before running it#

Plug in a mouse and keyboard, as well as a video projector (A screen can be used for testing) Then, plug in the power cable to start the Pi

Finally, plug the wii sensor bar.

Starting it#

Click on the raspberry in the top left corner, and go to "accessories" > "terminal"

Type the following commands to go to the right directory and launch the program:

cd digital_graffiti/

As the screen displays "connecting to can", press the + and - buttons on both remotes. One of them should have its first LED turned on, indicating that it got addressed as the first remote, and the other the second LED.

If the remotes stop blinking without leaving a LED turned on, press the buttons again to try the connection process again.

Launching again#

If the program crashes or if a child close it by mistake, simply press the up arrow key to bring the command back, and press enter to launch again.

Creating a desktop shortcut#

To simplify for non tech-savvy people, you can create a simple shortcut on the desktop.

Right click on the desktop and create an empty document called graffiti_numerique.desktop

Put the following content in the file, save it, and close it:

[Desktop Entry] Name=Graffiti numerique Comment=By EPN des Rancy Inc
Icon= Exec=xxxxx Type=Application Encoding=UTF-8 Terminal=false