Thursday, March 8, 2012

Origami Electric LED Fortune Teller v1.0

I had a free morning and limited supplies, but wanted to make an eTextile project. This project takes household materials - paper, tin foil, scotch tape, a few LEDs, a resistor and a 9V battery - and creates an interactive LED circuit that changes the color and LEDs that are lit when the fortune teller (also called cutie-catcher) is moved. Creating a flat circuit on a folded structure is very interesting because there are freedoms and constraints each time there is a fold or the edge of the paper. I took advantage of this fact when designing the circuit layout. While each trace is flat, they span three dimensions by changing sides of the paper and moving to a different section where folds meet.

Connecting the power was done with two alligator clips. A 500-ohm resistor was wired in series with the fortune teller circuit to reduce the current to the LEDs to a reasonable range. The blinking that occurs when two LEDs are lit (visible in the video above) is due to the split of current between the two LEDs. To avoid this problem, a resistor should be wired individually to each LED (so in parallel with each other when all the switches are closed). I want to keep the design as flat as possible in order to maintain the paper quality of origami, so I will use drawn-on graphite resistors made with a soft graphite pencil to version 2. This should solve the blinking problem, and allow for full functionality. 

The first step was to fold a normal fortune teller. Then contacts needed to be added to each of the inside flaps, so that when the two surfaces come into contact, an electrical connection is made.The LEDs are tucked into the corners and taped into place.

One center flap unfolded:

 Unfolded from the center:

Unfolded and flipped over:

Power connections on the base: