### Color Changing Textile

Due: Tuesday, February 14, 2011

Construct a color changing textile using: white cotton fabric, thermochromic ink, stainless steel thread, a switch, and a rechargeable Lithium Polymer battery.

The thread will need to carry at least 100mA of current to heat up enough to change the ink’s color. The Lithium Polymer batteries are 3.7 volts. You should use your multimeter and Ohm’s Law–which says that V (Voltage) = I (Current) x R (Resistance)–to determine the appropriate resistance of your stitching. Lady Ada has a good tutorial about how to use a multimeter here, and there’s an interactive web page on Ohm’s law here.

When you are finished, measure and calculate the following properties of your completed project:

• measure the resistance of each trace in your circuit and calculate the total resistance of the traces
• measure the voltage of your battery
• use Ohm’s Law to calculate the current running through your circuit
• measure the current running through your circuit

Create a post (on this site) that documents your project and measurements. Make sure to add your post to the the Color Changing Textile category. Your page should include:

• a table of the electrical measurements and calculations you made
• a few sentences describing your project
• pictures of your work in progress
• at least one picture of your completed project
• a short video of your completed project

Create a username and password for the site here. There’s a tutorial that explains how to make a WordPress post here.

Note: if you are already an experienced electronics builder you are encouraged to expand the project to match your skill set.

Bring your project to class on the 14th for demos!

Note: the pigment we are using for this assignment is from paint with pearl. According to the website it should change color from indigo to clear at 86 degrees F. You can purchase 25 oz. for ~\$50.