# 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: - YouTube

Any and all ideas welcome.

I am not a native English speaker. Do you mean you wear the dress and make it swing? An accelerometer will detect rotation so is a gyro.

Decide what effect you are going for and that will help with choosing a sensor. Gyros measure angular velocity (the speed of rotation) Accelerometers measure - you guessed it - acceleration. So someone twirling at constant speed has angular velocity but not acceleration.

However, the force of gravity appears to be an acceleration towards the centre of the earth, so you can use an accelerometer to measure tilt.

Using very small leds, it may be possible to simulate the dress from the video. My best guess though is that the lady performed her dance first and that the "leds" were video-shopped afterwards. Making a nice dress which lights up probably isn't extremely difficult from a technical pov, but it may be hard if you want to mimic the effects in the video as close as possible.

sirch:
Accelerometers measure - you guessed it - acceleration

Wrong!

So someone twirling at constant speed has angular velocity but not acceleration.

Guess who flunked physics?

However, the force of gravity appears to be an acceleration

Not exactly physics speak but yeah, why not?

you can use an accelerometer to measure tilt.

Finally got something right.

Personally I think dancing isn't turning around with a constant rpm but a lot of different moves. My best guess is that both types of sensors will respond while dancing. You can also ... find modules for only a few bucks on Ebay that house both type of sensors, called 6DOF, 9DOF or 10DOF-modules. You could test each type of sensor or even combine 'm in your program. Six degrees of freedom - Wikipedia

You wouldn't really need degree 7-9 for your project, a sensor that functions as 3d-compass, but you probably can create some astonishing effects with it as well. You could light parts of the dress for example, that appear to be standing still, while the dancer turns with great speed.

If the dancing lady dances with a partner who can throw her high in the air, you may be able to use sensor 10 as well, but to get different results on the altitude-meter the partner has got to be super strong

This was the sort of idea I had about fifteen years ago when LEDs were nowhere near as efficient as they are now.

Not dismissing the general idea but I see nothing in that video to suggest the use of LEDs. Orange and red gauze and sequins perhaps.

Thank you all for your responses. I've decided to get a gyro and acceleromter and experiment with them both. I also considered the sensors that have both in one, but I figure it's best to understand each as a separate entity before combining them.

I'm not trying to replicate the video verbatim (although that would be unbelievable if I could), just wanted to give an example of what I was trying to explain.

I want a "classy" lighting effect that might almost be unnoticeable until a twirl is done, as opposed to bright LED's. I'm thinking fiber optics may be more of what I have in mind.

Regardless, I'm sure I'll have many more questions. Thanks again for the comments. They have been very helpful.

cmarshal2617:
I've decided to get a gyro and accelerometer and experiment with them both. I also considered the sensors that have both in one, but I figure it's best to understand each as a separate entity before combining them.

No, do go and get one of the little boards that have both devices. You can get boards with only one, or with two, or three or four (accelerometer, gyro, magnetometer, barometer) but if you get them separate you then have to connect more than one board together.

If you get the board with the first two (or - three) then you only have to address the ones you want at a time and simply ignore the others, but you will not have to change connections to progress.

Also - note that there are digital and analog accelerometers and gyros. You want the digital ones.

I agree with Paul.

Difference in price between a board with single sensor and one with all sensors isn't very large as well. You probably pay more should nr1 not function as you want and by spending just a bit more you almost get "3 for 1".

The next one may be a nice one since the sensors have been used by a lot of arduino-users in a lot of different projects before, by just googling "Arduino + sensorname" you can find a lot of related examples/info.

P.s. they probably mean altitude in the title of the advertisement, but I'd really love to see a flashing dress with attitude sensor as well !!!

Yeah, get a combo board. I have 3-D accelerometer 3D-gyroscope 3D-magnetic and barometer (with temperature) for \$13 from ebay. Works nicely. I made a lab for some conceptual physics students to walk up down the stairs to measure pressure and calculate building heights. Agrees with stair height * # stairs within a few percents.