Color Changing MIT MechE

by rbatzer

I first tried to make a color changing sunrise, pictured below. It did not work well because the blue color changing paint was not dense enough to completely cover the orange and yellow sunrise. The thick blue layer also needs significantly more heat to disappear then the single Li-Po battery can supply so it only really works with body heat. The sunrise versions is show below cool on the left and warm on the right.

In my second attempt, I improved the construction by using an embroidery hoop and the stainless steel thread from the supply  instead of the bobbin we were supplied. The hoop kept my fabric flat while stitching so it did not end up crumpled like the sunrise v1.0. The steel thread from the supply has has a resistance of ___ as opposed to the small bobbin’s resistance of _____  so the MIT MechE design was able to generate more power.

I did not have a camera when I was working before I painted the design, so there is no picture. I made the design by drawing my design in pencil and sewing along the lines. I had several loops in my design, but I electrically isolated them by making sure the thread was separated by the fabric at each crossing.  After sewing, I painted the whole surface with a mixture of blue and red paint.

When the thread is electrified by the battery, the “MIT MechE” appears in red against a purple backgroud. The “MIT” part comes out clearly, but the “MechE” is a bit too small to be legible. Some areas have a double wide stich and these areas show up significantly brighter.


Before painting, I measured the resistance at 10 Ohms, but this value changed when the fabric is pulled taunt.

Voltage: 3.7 V

Resistance: 20.9 Ohms (after painting)

Current (measured): 0.19 Amps

Current (expected): 0.17 Amps