Soft Sketch: Building the Circuit

BUILDING THE CIRCUIT

After building my one pixel and being satisfied with the outcome, I went on to create another prototype focusing on the circuit build. I chose to make a 3×3 grid. Along with the circuit, I also wanted to try a thermochromic pigment, the pigment differs from the ink in that it dyes the fibers themselves, so it doesn’t change the texture and looks a lot slicker than a coating (the ink) laid on top of the textile.

Without a the proper machinery to put the fibers in proper dye bath, I was left to mixing the pigment with warm water and painting it on the surface. This was more of a “just cause I want it to be so!” moment. Hopefully in the future I can have the time or resources to really dye some fiber so I can felt my own hypercolor items! For this experiment though, it was fun to pretend

I designed my soft circuit in three layers.

Display Layer:

This consists of my handcrafted pixels sandwiched in-between two layers of felt. I screened the thermochromic ink on the top felt layer, the bottom layer I poked the two ends of the nichrome through to the other side. One end of the nichrome is hooked up to power, the other is connected to the collector pin of my transistor. While my circuit was still on my breadboard I used a TIP 120 NPN transistor. For my soft circuit, I opted for the the smaller 2N2222 transistors I found at radioshack.

Transistor and Ground Layer:

On this layer I poked the collector pin through the felt and bent it preparing it for the connection to the waiting end of my nichrome. On the other side of the textile, I curled the emitter pin and sewed each one to the conductive fabric traces I had laid out that were to go to ground. With the remaining base pin, I bent this up too and poked it through the third layer where I curled that as well and connected it to a 1K resistor.

Output Pin Layer:

This layer was permanently connected to the Transistor Layer by the base pin coming through and being sewn to the resistors. The other end of the resistor is then connected to soft circuit traces that I made out of conductive fabric. Each trace will lead to an output pin on the microcontroller.