Prototype 5

Prototype 5 is a plate to place under the front legs. There is also a small strip to put under the back legs. There is also a button to put the display back on.

Prototype 4

Prototype 4 is a plate that can be rolled in one direction, when it's rolled out it's stiff in the other direction. When rolled out, the scale has the shape of a plate. This can be used with both wheelchairs and normal chairs.

Prototype 3

Prototype 2

Prototype 1

Scale

We found a cheap scale in a 'Blokker' store. There are 4 seperate pressure sensors in it. These can be used to put under the legs of a chair.

First Ideas

These are the first ideas for the weighing mechanism:


Idea 1: 
This idea consists of presure points that can be placed under the legs of a chair. 

Idea 2:
This system can only be used on a chair with one leg. The advantage is that there's only one pressure sensor needed and there are less cables (less messy).

Idea 3:
This idea is basically some sort of add-on to use with a regular scale and a chair. The disadvantage of this system is that the display is not well readable. 

Idea 4:
This idea uses plastic tubes filled with water. The weight of the person causes pressure in the tubes. One can read the weight on the height of the water surface.

Idea 5:
This idea uses the system of a traditional scale with springs. (mechanical scale)