Conductive soil, video projection and Makey Makey

Description:

A demo set-up named "Groene vingers" demoing the Makey Makey board by utilising soil as a conductive material to switch between between two images. The switching and image handling is done within Isadora.  

Required components:

• 2 trays with moist soil
• Makey Makey board with alligator clips and aluminium foil 
• Computer running Isadora (Isadora patch via this link)
• A projector pointing at the table

Order from input to output:
- The 2 trays with soil form the positive and negative 'switchboard' of a circuit, which is closed when a person places both hands on it.
- The Makey Makey sensor board detects when the circuit is closed and sends for example the letter 'g' as a keyboard command.
- the 'g' key activity is detected in Isadora and used to fade between projections of photos, film and text and to start a sound.
- Using the projection mapping (a.k.a. video mapping) function in Isadora (see online tutorial), the images are projected in the correct perspective and within the frames of the trays.

Patch explainer:

1. Key strokes received from the Makey Makey
2. An algorithm preventing continuos keystrokes
3. A fading circuit to fade between projected images when a keystroke is activated by touch
4. Inverting the values for fading in an image while fading out the default image
5. Randomisation of audio startpoint to prevent repeats + green projection of displayed text
6. The default hand projection and movie which appears when triggered
7. An extra attribute to control the theatre lights