Makahiya: many changes and components search

Hi everybody,

As Tanguy said, this week has seen many changes in the definition of our project. Indeed, Alexis suggested to use a real living plant. Obviously, this choice adds several difficulties: a true plant needs water to live and thus we’ll have to design a waterproof product. Moreover, a real plant grows which can be a problem as we want to put wires on leaves. Alexis and us made some research to find an appropriate plant, one which keeps its leaves all the year long, that grows as slowly as possible and has quite big leaves. Tanguy already told about the stabilized plants so I won’t explain it again.  Yesterday afternoon, I went to Truffaut in order to have a better view of the possibilities. I exposed our needs to the vendors and they showed me several plants. A Yucca is too rigid for our project, and another plant that I don’t remember the name has too many small leaves. In this shop, they didn’t have banana tree, unfortunately,which was one of the suitable plant we had found. I finally decided to take a Calathea. It will at least help us to size our project.

This week, we have also begun to look at the components that we could use. We are almost certain to use Flexinol in order to make the leaves move. It will probably be the main factor that will affect the battery size. For the proximity detection, Lélio (from Expelliarose) lended us their magic sticks so we can see how they used the capacitive sensors. For now, the most suitable chip I’ve found is the PCF8885, made by NXP. It can have up to 8 inputs and 2 chips can be connected in order to get up to 16 inputs. Moreover, it’s clearly stated that it’s possible to use remote sensing plates. We still have to check the minimum and maximum dimensions of the sensing plates before validating this choice.

Next week will be mainly dedicated to components selection.

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