Prototype 3 with Flexinol

We had a successful day of prototyping. We made a simple prototype by attaching the foil - parallel capacitor to the end of a long strip of chip board, and attached flexinol to the ends of the chip board. Here's the basic setup:

With the sensor as an integral part of the moving armature, the distinction between input and output blurs.. we were inspired by the 'Reef' installation at Storefront for Art and Architecture by Radical Craft. While that installation used separate motion sensors to trigger the response, we are interested in using a conductive armature or skin as a sensor itself.

The prototype in action:




As your hand gets within about 2 inches of the foil, the flexinol is activated and the piece moves to meet your hand. In an array, this type of functionality could create a wall surface that is sculpt-able by simply the wave of your hands... an architecture which tries to cuddle with you... which follows you around... lets in more light and air where there are people...

Things we tackled:
- On/off based on proximity to the foil.
- Flexinol on a relay from a 9V battery.
- Armature for the flexinol with a pretty good first response.

Issues & Next Steps:
- Predictability of the response coming from the parallel capacitor. Our first prototype got us consistent values ranging from 0 (hand 12" or more away from the foil) to 60 (hand within about 1" or touching the foil). Today, the results were much less predictable. We think that with careful grounding/insulation and the right metal this can be solved.
- Integration of the metallic 'sensor' part of the armature and the non-metallic part... The metal, for one thing, would probably be better on the back side of the non-metallic 'fin' so that there is an insulating buffer between the user's hand and the capacitive sensor. Maybe this could even be a simple coating?
- Careful grounding of the Arduino board, the foil, the flexinol and all the wiring. This is essential because they interfere with each other and we want to be very specific about those interactions.
- Possible different responses based on varying proximity to the sensor. This requires both consistent input (1st issue) and variable output, which may mean we investigate a servo or other more specific output. (Flexinol, for all its beautiful organic movement, is a binary actuator.)
- We have lots of ideas for architecturally 'programming' the system, but picking one will help us design future components.