Ok, I started with the idea that I would paint Kermit and reveal an xray below him. Which would be a hand. Classic puppet joke. So I mixed yellow thermochromic pigment, yellow acrylic paint, blue acrylic paint, and mod podge. Which, as we all learned in kindergarten, makes green. Kermit green. I painted Kermit on top of the skeletal hand and let him dry.
Then I tried it out with the heat gun. No dice. Here’s the problem: the paint wasn’t going anywhere, only the pigment itself would disappear. Lesson learned. Onward! With constraints built in of only having yellow and red available, I made an apple. Beneath the red pigment (mixed with mod podge) was the image of an apple core. Heat it and the apple is eaten. Tried it with the heat gun. Bam. Apple gone, core here.
Next! Let’s add the Arduino and a button. Simple, right? No. I wanted to heat the entire area of the apple, so I tried using copper taffeta. Fail. It doesn’t heat it up. Fine, I will sew with conductive thread. Cool?
NO. It heats in a very specific line, mysteriously reflective EXACTLY of the thread. The heat doesn’t spread. Fine. This would work to heat a very specific line. I’m done here.