How to shoot photo with ROS for geotag

Hi, I have an hexarotor with pixhawk v1 and arducopter. I have a raspberry pi as companion computer with a webcam and mavros.
I would like to make a georeference survey but I don’t have a hardware triger device. Is there a way to use mavros to trigger the web cam? is there another way to make geotagging mission with my setup?


you can specify an AUX channels of pixhawk for this purpose and trigger by radio control like this

you have to write an python script that listen on raspberry pi for input signal from pixhawk

Ok, I’ve managed to make a python node that subscribe to mavros /global_position/global and to usb_cam /camera_rgb/image_raw and after synchronize the messages, save the image and the write exif data. I have to test it on a flight mission, but I think it is working.