# Conductive soil, video projection and Makey Makey
[](https://bookstack.hku.nl/uploads/images/gallery/2023-11/img-1017.jpeg)
**Description:**
A demo set-up named "Groene vingers" demoing the [Makey Makey](https://makeymakey.com/) 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](https://nextcloud.hku.nl/s/sDmGtM4PjZkmSpz))
- 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](https://www.youtube.com/watch?v=mEWWxPE3ZkQ&t=18s)), 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
[](https://bookstack.hku.nl/uploads/images/gallery/2023-11/screenshot-2023-11-20-at-15-56-04.png)