(Update02)An alternative way

The battery tester was an invetion combining two exsiting technologies - conductive ink  and thermochromic ink.
And the other ongoing project proposed by PHILIPS is "Emotion Sensor", which will make use of the conductive ink(colour display) and textile sensor(sense emotions)
I am thinking that, instead of finding a new kind of SUBSTANCE, which will change properties due to certain outer stimulus thus result in different colours in appearance  (the material science or chemistry students might be more competent to do so), it is more feasible for us to find a novel way of making use of the current technologies, (eg. thermochromic, conductive ink, electrochromic materials, conductive thread, textile sensor, etc.) to invent a new kind of MATERIAL, which could be integrated into fabrics, and that we will also be able to control the colour change.
Related websites:
thermochromic battery tester
PHILIPS emotion sensor
However, as far as my research reaches, the current technology only allows gradual change between two certain colours (eg. thermochromic leucodye & photochromic ink). Ideally, to achieve change between more than two colours, we could apply multiple layers of colours.
An alternative way is to use a matrix.
The video below illustrates the idea of use matrix to achieve the effect of multiple colour displaying.
(The vido is made by myself, please kindly view it and give some comments.)

An Alternative Way