Color Changing Flower Applique

by anasto

Using thermocrohmic paint, cotton, conductive thread, a switch, a battery, and some scrap fabric, I made this flower applique. This could be used as a decoration that is sewed or glued onto a variety of garments, or perhaps fastened onto a safety pin or a hair barrette.

Using a multimeter, I made these measurements:

  • voltage of the battery: 3.7 volts
  • resistance of traces: 1 Ω and 22.4 Ω

Using Ohm’s law, V = IR, I calculated that the current should be 158 mA, which would be enough to change the color of the ink when the current passes through the thread. However, when I measured the current with the multimeter and the battery plugged in, I got a reading of 78 mA, which is slightly below the threshold for color changing.

This video shows the applique with the switch on. The color change is quite subtle, probably due to the fact that there isn’t much current going through.

First, I stitched the circuit components and a circuit using conductive thread.

Then, I painted the fabric with thermochromic paint. I tried a few colors and found that this green color showed the most dramatic color change. I discovered that the trick was to use only a little bit of regular paint mixed in with the thermochromic paint.

Then, I stitched some layers of sheer yellow fabric and red fabric for the flower’s center. This layer conceals the underlying circuitry.