| Pan / Tilt calibration |
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Transmitter settings: endpoints / servo rates
First, let's make that in manual mode you can use your transmitter to move pan and tilt as far as they can go physically in all directions.
In your transmitter, make sure the "servo rates" and "endpoints" on the pan and tilt channels are as high as possible. This is "120%" or "125%" on most transmitters.
Also be sure there is no trim on either channel.
Power up plane and transmitter. Switch to manual mode.
Move the pan control all the way the right. If you hear binding / buzzing of the servo, back off a little until it just stops buzzing. In your transmitter settings, set the "endpoint" for that channel to that position.
Repeat for pan left, tilt up, and tilt down.
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Calibration via video
Instead of using a protractor, let's use trigonometry and the image from the video camera to calibrate pan/tilt angles. This will give the ultimate precision.
Set up video receiver and monitor. Be sure there's a SDFlash chip inserted in Ruby.
Measure and mark dead center on the video screen with a little piece of tape or erasable marker..
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Set plane up on the edge of a table facing a wall as shown. Be sure it's parallel to the floor and facing the wall squarely.
Measure the distance between camera and wall. ("a") and between camera and floor ("e").
Place a mark / tape on the wall that is directly ahead of the plane and at the same height from floor as camera. We'll call this ("y").
Place a mark/tape on the floor that is directly below the camera. We'll call this ("z").
Move pan and tilt so that the center on the video screen centered on ("y"). Be sure the tilt control stays in the same position through the next steps.
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Move pan control to center. The camera should be pointed about 45 degrees to the left of the plane centerline.
Measure the distance ("b") on the wall between ("y") and the point on the wall corresponding to the center of the video screen. This should be at the same height from floor as ("y").
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Move pan dial all the way to the right. The camera should be pointed about 45 degrees to the right.
Measure the distance ("c") on the wall between ("y") and the center of the video screen. |
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Rotate the plane 180 degrees, so it's squarely pointed away from the wall. You might need a helper or to find some creative way to keep the plane on the table, level with the ground.
Measure the distance ("d") on the wall between ("y") and the center of the video screen. |
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| Move pan and tilt so that the center on the video screen is centered on ("y"). You'll have to pan a little to the right to achieve this. Be sure the pan control stays in the same position through the next steps. |
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Move tilt control to center.
Measure the distance ("f") on the floor between ("z") and the center of video screen.
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Move tilt control all the way up.
Measure the distance ("g") on the wall between ("y") and the center of video screen. |
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Move tilt all the way down.
Measure the distance ("h") on the floor between ("z") and the center of video screen. Note whether the distance is closer or further from the wall than ("z").
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Send the above measurements along with the "data.utd" file that was generated as you collected them. I'll do the trigonometery to determine all the angles. |
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