What is the correct sensor?

I’m extremely new to both electronics and tailoring, so I thought it would be a good idea to combine the 2 in my first project.

Background: I have the Arduino starter kit and misc supplies. I’ve made a pair of pants.

I would want to make a dress that has LED’s at the bottom section of it. When twirled, I want the LED’s to either brighten or fade to another color (haven’t decided yet)

The question is: What is the right sensor to do this? I want the change in brightness (or change in color) to be very smooth.

Do I measure Force, Tilt, Acceleration, wind speed?’

Here’s what I’m going for: http://www.youtube.com/watch?v=J8LDUlS98UE

Any and all ideas welcome.

thx in advance

Since twirling is a form of rotation, I’d say a gyro. Which measures rotation in terms of degrees per second, or radians per second. Since most gyros measure on multple axes you may be able to differentiate between the horizontal twirling rotationand the vertical ‘lifting’ rotation of the dress.

As for driving the leds, the gyro normally gives out a voltage level. Some only with a digital serial interface. But most likely the voltage output is not sufficient, and not with enough current to drive leds directly. For that you might need a small microcontroller (to modulate the led intensity… add a flash) that drives a transistor valve-ing the current through the leds.

I think everything you need can be found among the Lilypad offerings, which are all designed to be sewn into clothing. They are programmable with the Arduino package. Lots of exciting ideas at http://lilypadarduino.org/

For your dress, the three axis accelerometer might work but it will probably take some experimentation to figure out how to distinguish whirling motion from any other motion. This could be a real eye-catching project, so keep us informed! https://www.sparkfun.com/products/9267

I’ve decided to go ahead and get a accelerometer and gyro and experiment with both of them. I will be getting a lillypad as well. I’m sure I’ll have many more questions to come. Thanks to both of you for your input.