PWM Camera Trigger to companion computer

Hardware Companion Computers
1

I am currently an undergraduate mechanical engineering student who recently got into developing and have a question about a project I am working on.

Here’s what I have:
• Pixhawk Flight Controller (Px4)
• ODROID C2 (Running Linux Ubuntu 16.04)
• oCam-1MGN-U (Rev. 16 A)
Here’s what I have done:
• Running oCam viewer within Linux
• Set up companion computer (ODROID C2) communication to flight controller (Pixhawk) via MAVLink (note: I did this by following this guide http://ardupilot.org/dev/docs/odroid-via-mavlink.html , for what it’s worth, I connected telem2 with an FTDI cable.)

Here’s what I want to do
• Once I plan my drone’s flight via mission planner, I want the flight controller to trigger the camera via PWM signal carrying the metadata such as latitude, longitude, orientation altitude. I then want the companion computer to be able to accept the PWM signal and store sed images with metadata attached.

If there are any resources or tips you all would like to share for developing a code for this all is welcome. If there are any extra questions as far as equipment or anything else just ask and I will be happy to provide.

Thanks

2

I’m using Dronekit for a quite simple method to get all relevant informations out of the Mavlink stream. Then, I have a extreme simple external board with a CD4013 connected to one of the GPIO of (in may case) my Pi. When the PWM reaches about 1500, the connected GPIO pin gets triggered. Google for RC switch and CD4013, otherwise I’ll give you the simple schematics. When the FC triggers the “camera” , I use the telemetry data out of the Dronekit vehicle object and tag the image simply by calling the exif-tools out of my Python loop. No rocket science :slight_smile:
Alternatively, you can configure the camera trigger as relay instead of servo. So you do not have to handle any PWM signal.

Stefan