DROTAG Beta Testing- Trigger, Geo Reference and Configure your Camera

Hello there.

It has been a while since I posted in these forums but I have been busy at work with our new product DROTAG as a stand alone board. I am providing here instructions for you to try out DROTAG software in your Navio free of charge for one month.

What is DROTAG?

DROTAG is a system that allows almost any digital photography camera to be Configured, Triggered and Geo-Referenced images with APM position data in the air with a normal USB cable. One system, one simpler workflow: compatible with many cameras. The compatibility list is in gphoto2 page.

With DROTAG you don’t need any offline post-processing after you land to get your pictures geo-referenced. DROTAG does all that in the air. The pictures will also be in a separate folder for each power cycle. This way you don’t have to sort pictures from other flights. Effectively each flight will have its photo folder. DROTAG just gives you a simpler workflow.

How to get it in your Navio?

  1. Login to your Raspberry Pi through ssh and have the Raspberry Pi connected to the internet.
  2. echo “deb https://www.airborneprojects.com/debian binary/” | sudo tee -a /etc/apt/sources.list
  3. sudo apt-get install apt-transport-https
  4. sudo apt-get update
  5. sudo apt-get install drotag

That is it. DROTAG is installed, but for now there is a need for manual configurations because there are some options available.

What can you configure?

  • You can choose whether and where to live stream your full resolution pictures.
  • You can choose where to save your pictures (external USB pen or Navio Memory card)
  • You can choose the photography parameters.
  • You can enter a special mode that makes CHDK cameras tag the images in the camera card.

How can you configure:

DROTAG files are in /opt/DROTAG/. In this directory you can find AP1.conf, the master DROTAG configuration file.
In this file you will find a section called server, which is the relevant part.

  • send_period: is the timeout value of the main loop. Should not be changed for now;
  • gstreamer: the section corresponding to the general camera settings;
    • enable_gstreamer: True or false, signaling whether gstreamer should be used by DROTAG. Incompatible with enable_gphoto2.
    • sources: The only parameters you should change in this section are the camera settings. Be aware that the camera settings need to be connected to the reality of your camera, otherwise bad things may happen. To verify the capabilities of your camera install gphoto2 and run gphoto2 --list-all-config.
    • sinks: the section where you select the destination of the pictures.
      • selected: The index of the configuration for the destination of the pictures. Only one can be selected.
      • available:multifile:location: The location to save the pictures. This is a path that must be writable and can be an USB pen drive or any path accessible to Raspberry Pi.
      • available:udp:port: The port of the computer that will receive the pictures
      • available:udp:destination_host: The address of the machine that will receive the pictures.
      • other paramerers: should not be changed for now and are irrelevant for DROTAG.
  • mavlink: Parameters regarding mavlink
    • enable_mavlink: true or false. If enable_mavlink is false and enable_gstreamer or enable_gphoto2 is true, the DROTAG will work in intervalometer mode according to send_period.
    • selected: and index number of the selected mavlink interface. For the case of Navio it should be 0, for udp.
    • available:port: this should be the udp port where the ArduCopter binary running on navio is sending the mavlink telemetry.
  • gphoto2: section corresponds to CHDK triggering configuration
  • enable_gphoto2: cannot be true while enable_gstreamer is true;
  • trigger_mode: should not be modified;
  • trigger_script: is the path for a CHDK lua script you may like to use to configure your camera;


In your /etc/rc.local the ArduCopter-* you use should have a telemetry output to localhost udp port. It should also launch DROTAG. E.g:

#!/bin/bash cd /opt/DROTAG/ ArduCopter-hexa -C udp: & ./DROTAG &

To test your configuration you can run it in a shell:
sudo /etc/rc.local

Mission Planning

DROTAG requires the DO_DIGICAM_CONTROL command which triggers the camera shutter.
This command should be executed every time a camera trigger is required. When drawing your grid in Mission Planner you should define this command as default.
One important point of confusion that some clients have expressed is whether the Servos or Relay pins should be configured. The answer is No! The actual trigger does not have any mechanical or analog component.

Manual triggering from Radio

If you want to manually trigger DROTAG you can configure a RC channel to it. For this follow the instruction taken from Ardupilot documentation page for example for channel 7:

  • Open Mission Planner and then click on CONFIG/TUNING | Full
  • Parameters List
  • Set the value of CH7_OPT to 9
  • Write Parameters and reboot.

The camera should now trigger on channel 7 toggle.

Hardware considerations

With DROTAG you should not need special USB cables for most modern cables as most of them take a miniUSB or microUSB. We have experienced increased performance (smaller time between pictures EST) with better cables. Feedback would be appreciated

Make sure your camera is powered and connected to the Raspberry Pi before powering the whole system.

Request for comments on installation directory

We would like to make DROTAG configurable without SSH login. In the preconfigured board we sell we achieve this by putting the binary and the AP1.conf configuration file in the boot partition. This boot partition is visible even in Windows so taking the card off the Navio and reading it in your desktop can be used to change the parameters of AP1.conf.

Besides the convenience above if the boot partition is resized to a bigger size it can also be used to store the pictures, which then are also visible in a normal Windows computer.

The problem with this approach is that a disk image would be much easier to work with. All the above steps would not be necessary. What do you think about these approaches?

Request for information on additional functionality and usability

If you think some usability is missing or an additional feature would make you a buyer, let us know.

Request for comments on price

If it worked for you how much would you be willing to pay for this software?

Request for information on cameras

We would very much like to hear feedback on cameras which work with DROTAG and are available to give out the full version of the software for the best testers.

1 Like

Hi Paulo! The project looks awesome, is it still available for testing? I was also looking at the gphoto2 page and wondered if it is possible to stream the pictures taken by the camera stored on the Pi to send to the ground via 4G connection. It would be nice to see (some) of the pictures while you fly, for quality control purposes.