Next to Instructables the Evil Mad Scientist Laboratories is one of the interesting sites I regularly scan for simple, eTextile suitable projects.
As LEDs are one of the favorite components eTextile artists are using I had a look around on how to make LEDs come to life when it makes most sense – when it goes dark.
Sensors often require the use of a micro processor which usually cost some money and can be a bit challenging to use by occasional electronic users like the eTextile community.
The Evil Mad Scientist has the solution: a phototransistor, a transistor, a 1k resistor and an LED.
Click over to the instruction where you can find also the theory behind this simple yet effective light sensor to switch on the sparkle by magical low tech.
Mika Satomi and Hannah Perner-Wilson have posed on ‘How To Get What You Want‘ another variant of this simple sensor using a 100k ohm potentiometer instead of the 1k resistor which allows to adjust the level of low light by which the LEDs should switch on/off.