It's a fun project!

Step 1: Thermochromic Ink

I use the thermochromic ink to paint to each card

The mixture are

- Thermochromic Ink powder (20 g)

- Fabric Glue

- Water

Step 2: The Heat Pad

I use the circuit done above and plugin with the 9v Battery to get my conductive thread heat up :)

The white dashed line is the conductive thread the black is ground and the red one is the power!

the AR app was done by Unity using Vuforia to make it happen.

This is a series of the AR tutorial I watch to get it working :)

https://www.youtube.com/watch?v=9XikHnTiukk

The video shows the process and how to play with the cards