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About Spin Meter

Once upon a time, phones had cords, if you can believe it, and those cords, if they were long enough, would inevitably twist and tangle and knot themselves up as the person using the phone turned and paced around during a conversation. That problem is mostly nonexistent these days, thankfully, but people still pace and spin when they talk on the phone.

This little app measures how often you spin, and in which direction, while you are walking. By using it you can find out if you are a left-tending person or a right-tending one (literally, that is, not politically!).

Instructions

Launch the app and select "Spin Measurement" to view the list of past spin recordings.

Create a new record by tapping the "+" in the lower left, or continue an existing one by selecting it from the list.

Selecting a spin recording starts the "Spin Meter". The app then monitors whether you turn left or right. A right turn counts as a positive; a left turn as a negative.

The Spin Meter measures the direction of your spin regardless of in which direction the iPhone is pointing and has a screen locking option (this saves some power).

Definitions

The "spin" is the sum of full (360°) rotations, where a clockwise rotation counts as a positive and counterclockwise counts as a negative. The "twist" is the sum of all angle movements, where every movement counts positive.

Visualization

The app shows your current spin as a twisted band. It also displays the numerical value of your spin, as well as the speed in rounds per minute.

Why you are "Spinning"

There can be different reasons why you have a preferred direction when turning:

• It could be environmental. For example, if you walk by a store with its entrance to the left, you turn left 90° to enter the store (spin -0.25). Inside the store, if the counter is to the left, you will again turn left 90° when approaching it (spin -0.25). To leave the store, a left 90° turn is generally more natural than one 270° to the right. Continuing your walk will add another left 90° turn, resulting in a full 360° left turn.
• Or, it could be purely personal. Your body may just prefer to turn in a certain direction. If so, this app will reveal that and show you if you are a "leftie" or a "rightie."

Remark

Mathematically "spin" it is defined given by the integral $\int d\omega (t)$ while "twist" is defined by the integral $\int |d\omega (t)|$ (the total variation).

Notes

Requirements

This app requires a compass (iPhone 3GS)!

Running the app can be demanding in terms of power consumption because it constantly polls the compass. You can put set your phone on stand-by (press the hold button).

Limitations

The accuracy of the spin meter is limited by the accuracy of the iPhone's compass. Very fast turns (faster than a round per second) are difficult to track.

Feedback

Please send feedback, error reports or feature requests to email@christian-fries.de.