Pixhawk based UAVs can automatically take pictures at a set distance using GPS
distances or points.
In order to do so you must configure your Pixhawk, Install
CHDK on a
compatible Canon Powershot camera,
KAP UAV Exposure Control Script, and connect the Pixhawk to the camera
with a trigger cable.
Configure your Pixhawk
Use Mission Planner to connect to your Pixhawk
based UAV. Go to CONFIG/TUNING > Full Parameter Tree and set the
- Some setting will be Out Of Range. Accept anyway.
- You can use RC 9 through RC 14.
Install CHDK on a Canon Powershot camera.
CHDK is free, non permanent software that runs in
addition to the firmware on certain Canon cameras. Among other things,
it allows you to run scripts that can remotely trigger the camera by
sending a signal through a USB cable. It is
installed on the camera's SD memory card, so no modifications are made to
the camera. The easiest way to install CHDK is by using a program called
Follow Stick's instructions to install CHDK on your camera's SD
Follow the CHDK
instructions for loading and using CHDK on your camera.
Configure KAP UAV Exposure Control Script
KAP Exposure Control Script runs under CHDK
and automatically controls shutter speed, aperture, ND filter, and ISO
settings so as to maintain the fast shutter speeds needed in aerial
photography. Additionally it allows you to trigger your camera by
sending a PWM signal to the camera's USB port. Do the following to
install and configure KAP UAV Exposure Control Script:
Download KAP UAV Exposure Control Script. (kap_uav.lua)
Copy kap_uav.lua into your (SD Card:)\CHDK\SCRIPTS.
Lock your SD card, insert it into your camera, and turn your camera on.
Press the Play button.
Press the FUNC SET button to select the Script Menu.
Press the FUNC SET button to Load
Script from File.
- Select KAP_UAV.LUA using theOuter button and FUNC SET button.
- Set Shot Interval (sec) to Burst.
- Set USB Shot Control? to Pixhawk. Press the Menu button to exit the KAP_UAV.lua options.
- Half Press the shutter to start KAP_UAV.lua.
- Your camera is ready when you see Waiting on USB.
- The default exposure values should work on a sunny day. If
necessary, use the
KAP UAV Exposure Control Script documentation to
Connect the camera trigger cable
camera cable is required to trigger your Canon camera. As your UAV
flies past predetermined points, the Pixhawk will provide a pulse to the
RC Channel you specified.
Do the following to
verify your system is
Connect the servo style connector from
camera cable the RC Channel you specified on the back of your Pixhawk.
Note! the Pixhawk
does not provide power to the AUX OUT pins. You must provide 5 volts
to the AUX OUT pins by plugging in an ESC with a Battery Eliminator
Circuit (BEC) or a
Universal Battery Eliminator Circuit (UBEC) into any open pin
set. Read here to determine if you need a BEC.
- Connect the mini USB connector from the
camera cable to the USB port on your Canon camera.
- Turn on your camera with CHDK and start the
so that waiting on USB signal is displayed.
- Start Mission Planner, Connect to your Pixhawk and go to the
Flight Data screen.
- Right-click on the map and select Trigger Camera NOW.
If everything is setup correctly your Pixhawk will trigger the Canon
camera to take a picture and is capable of triggering pictures using
- Make sure you don't have more than one RC#_FUNCTION set to 10.
- Make sure you don't have RELAY_PIN set to the same OUTPUT channel that you have RC#_FUNCTION set to 10.
Your Pixhawk can't do both.
Errata, kudos, email@example.com