Color Changing Textile – skipping stones

by yihyun.lim

Completed small swatch of color changing textile activated by 4V battery.

Here’s a short video of the color changing in action.



non-conductive fabric (cotton)
conductive stainless steel thread
3.7V lithium polymer battery
thermochromatic ink

I wanted to create a small pattern of beach pebbles in different colors.
The conductive thread stitches would form the white pressure lines of the pebbles, so when the stitches heat up (with the power from 4V battery), the color of immediate adjacent area next to the conductive thread would turn clear.  First I sketched few different pattern options as well as stitching pattern, then I outlined the selected pattern on the cotton fabric. It is now ready to be sewn. I doubled the conductive thread to make sure the pattern had enough resistance.

With the completed pattern, I took it to the Lab to start applying the thermochromatic paint. The main thermochromatic paint color was blue, so I added just a little bit of other colors to the main blue color to achieve various shades. One thing to remember was not to add too much of other colors to the thermochromatic mixture, otherwise the thermochromatic mixture would get diluted. So below is the first layer of paint applied.

Using the multimeter, I measured the resistance and current within the circuit.

resistance: 11 ohms

given the equation V=IR, anticipated current was:
I=336 mA

measured current was = 137 mA (much less than calculated)

When I turned on the switch, the color change was so subtle that it was almost unnoticeable. I applied another coat of paint, especially near the stitch area. This time I could definitely read the area near the stitch line turning brighter.