The Teknikio Light Sensor Board is the easiest way to activate your sewable projects with light.
It runs off a CR2032 battery and has two modes: simply connect the sensor in your circuit to sense "light" or dark". It's easy to use with textile, paper, and other materials.
In "light sense" mode, the sensor will trigger an output to turn on when it senses light, and turn off when it sense dark
In the "dark sense" mode, the sensor will trigger an output to turn on when it senses dark, and turn off when it senses light.
The voltage (and hence current) supplied from LIR2032 rechargeable coin cell batteries may damage the Teknikio LED boards, so please ONLY USE CR2032 3V COIN CELL BATTERIES with the Teknikio range!
Teknikio make a range of fun and beautiful sewables (or stickables - you can use them in origami/papercraft projects too), that are designed with children and education in mind, but they suit explorers, inventors, and curious minds of all ages: 8 to 108!
They've also put together a couple of fab guides on sewables and origami to teach you the basics and give you some project ideas.