Clinometer on iPhone / iPod Touch
This clinometer * application is a (hopefully most accurate) slope finder tool on the iPhone. It can be applied on all edges of the iPhone/iPod touch (preferrably the ones without buttons) in every direction. It is designed to be as accurate as possible (normally in the range of ±0.1 degrees, although this might depend on the device).
The clinometer supports multiple color schemes (Black on White or White on Black and Night Color) and 2 precision setups. A fullscreen mode can be toggled by tapping the center of the screen, which prevents you from erroneous inputs while measuring.
The (free) update is already distributed which includes nicer graphics, two-way calibration, a percentage display, and a bubble mode when the iphone is on a flat surface.
You can calibrate the device in five directions independently. This is because the accelerometers give different deviations for each axis. However you can easily choose to calibrate the directions on demand.
Switch off the fullscreen mode (tap on the center on the screen) in case you don't see the buttons on screen. Put the device flat on a table or hold the device in one of the four directions perpendicular to the surface (bottom side down, bottom side up, left side up or left side down). While holding the device, press the button that automatically gets enabled if you are holding the device correctly. Then just click finish and the calibration should be accurate as long as the surface was properly leveled.
If you are not sure if the surface you are using is levelled, you
can choose to do a two-way calibration. First, start with the bubble
calibration. Put the device flat on a table. Press the Bubble Up button.
Then rotate the device by 180° as shown in the picture below.
When the indicated level has stabilized, press the Turn and recalibrate
Now hold the device with the left side up. While holding the
device press the button that automatically gets enabled if you hold the
device correctly. Then rotate the device so that the left side is facing
upwards (see picture below). Press the Turn and recalibrate button.
Repeat the same procedure for the right side up. You may choose a level
surface on the upper side to use as a reference because otherwise the
volume buttons will be located between the surface and the device which
will prevent an accurate calibration.
Finally repeat the steps again with the botton down (as shown
below) and bottom up sides. With respect to the bottom up side, since
the power button is on this side, you should use the top of the iphone
as a reference instead. For example, you can use a door frame or the
ceiling (if you are tall enough) as a reference. If you find a better
reference point, please share your experience.
Further information and contact
According to wikipedia: An inclinometer or clinometer is an instrument for measuring angles of slope (or tilt), elevation or inclination of an object with respect to gravity. It is also known as a tilt meter, tilt indicator, slope alert, slope gauge, gradient meter, gradiometer, level gauge, level meter, declinometer, and pitch & roll indicator.
For recreational use only. After the calibration it CAN (!) be very accurate especially for the main axis after calibration. The measurement is performed as good as possible (we try our best) by using the three inbuilt accelerometers.