This is a special version for aerial photography. On the plane there is a stabilized camera.
Here is the camera stand. Guess what is the weight of it? ;-)
I have also made additional code to APM, so I don't need a computer to make flight plan. The procedure is following:
I go near the target I want to photo. I press "Locate" button and switch power on. The Ardupilot now waits until it has good gps fix, and then makes automatically flight plan around this place. Then I can switch off the plane and walk to a good starting and landing place. There I again switch plane on, wait gps fix and throw plane to flight. Plane makes three rounds around the target.
First round radius is 250 meters, next 200 and innermost 150 meters. Altitudes are 80, 70 and 60 meters. There are two checkpoints, 1 and 2. Plane should first go to northeast then turn to left, and after that turn to north west. If plane does not do these curves, there may be something wrong with the flight plan, and it is probably best to call plane back.
I have made Canon CHDK system to camera, and I can launch it with remote control channel 5 switch. Normally I take photos all the time. After flight I have 150 - 250 pictures, and probably at least one of them is good :-)
The Locate button is simple circuit. Normally AN6 is connected to GND with resistor, so the voltage is 0V. If I press button in the start, the voltage is 5V, and program goes to special subroutine that calculates this flight plan.
I have not tested this, but it would be easy to add more predefined flight plans to plane. In this draw there is Locate button and knob selector. If user does not press button, the AN6 is zero. If user press button, then those resistors are voltage dividers, and AN6 is something between 0V and 5V depending on knob position, and program can branch to desired subroutine according to the voltage. For example one of them may be subroutine to take orthophotos from square field.
The code for flight plan? This program writes coordinates to Eeprom, and I am not familiar with those details. If someone who knows code can check it and then share it?
Code for camera stabilizer is here
Here is an example of photos.