HeliPitch is an application for controlling the rotorblade pitch angles on your remote controlled heliopters. It uses the preview video stream of the videocamera in your iPhone. The application uses image processing to identify your rotorblades and once identified, it will approximate these with lines that gives the angle. All is done in realtime and typically it will process the images in 4-5 fps on an iPhone 4.

To work, you should fold the blades backwards (aligned with the boom). By doing this, the actual pitch angle can be measured as taking the angle between the blades and divide this with two. To get the application to work it is best to follow a few rules:

- Avoid to have many 'lines' behind the helicopter that can be mistaken as rotorblades, i.e. same length, angle etc.
- Make sure that the blades fill the aiming box, but are not larger than this box.
- Make sure that the rotorhead is held within the aiming circle.
- Try and hold the camera as still as possible and avoid motion blur.
- Take a few measures and check that is seems ok.

I cannot guarantee the quality of the measurement. If you are unsure, you should not fly without checking the pitch angles in another way. I cannot be held responsible for personal injury or damge to your iPhone or helicopter.

This is a sample screenshot of how it can look. This is taken when testing the application on my T-Rex 550. Note the digital bevel box showing 10.3 degrees and the HeliPitch app showing 10.2 degrees, not far away!


The application uses OpenCV (BSD license). Please visit opencv.willowgarage.com for more information.

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