08-06-2021 07:26 AM
does anyone have experience with triggering multiple GoPro cameras at the same time with labview? Specifically, it's about taking different measurements, both visually and via sensors. Since multiple cameras are to record at the same time, it makes sense to have the sensors and cameras both triggered at the same time and in the same development environment. A wired solution would be my preference, either via USB or HDMI. I would also like to avoid disassembling the cameras to trigger them with a signal generator (TTL). This means that the videos are not to be further processed, nor is the data to be stored on the PC direktly. So it would be purely about the synchronous start of both cameras. What I already found out is the usb manufacturer id (vendor id) and the usb model code (product id) via the ni-visa driver wizard. I'm not exactly sure right now if this information is of any use to me and if I can use it as an address to control the cameras. Unfortunately, the suggestions in this forum so far have not helped me. I am very grateful for any advice and would be very happy for any shared solution. Thank you very much for your help and information.
08-06-2021 07:56 AM
Depending on what your definition of "at the same time" is, it almost certainly will rely on a physical trigger exactly like the one you don't want to use.
08-06-2021 08:06 AM
So by simultaneously I actually mean that both start recording at the same time (maybe with a small delay) regardless of whether there is a delay of a few ms from running the program to starting the recording. Is there any possibility at all to control the GoPros via USB or HMDI?
08-06-2021 08:39 AM
I believe that neither the USB nor HDMI cable have a line reserved for a TTL signal, generally used by "triggerable" cameras to "start Video recording". I don't know what the GoPro API supports, but I suspect it also does not have a "Trigger" or "Start" digital input. This makes it unlikely to get two GoPro cameras to synchronize unless you synchronize two versions of LabVIEW Vision to start them.
One way you could do this would be do have two RIO processors that support LabVIEW Vision, one per GoPro, and each running their own LabVIEW Vision acquisition routine. They would be connected to the Host, and when the Host sent a TTL signal to both of them, they would both start their respective Grab sequences. This would probably work, but would be relatively expensive (an order of magnitude more expensive than the cameras, I suspect).
08-06-2021 09:08 AM
Unless GoPro provides some sort of API that you can use to fake a GoPro remote you are basically SOL
08-06-2021 10:21 AM
Well look at that...
ANNOUNCING ‘OPEN GOPRO’ API + NEW HERO9 BLACK FIRMWARE
08-06-2021 11:47 AM
Thanks for the answers.
I also saw that GoPro recently made an API available. The real problem is, there was already an unofficial API for Python. I also tested this to trigger my camera. But just one camera. Also, it seems very random to me when the program executes the commands and the camera starts recording. So I want to do this via LabVIEW.
Unfortunately, it is also the case that you have to connect the gopro to the PC via Wi-Fi. I have no idea how to connect 2 GoPros to the PC at the same time via Wi-Fi. I will try again with bluetooth. That should be possible then. Nevertheless: even if it works with python, I want to synchronize this with LabVIEW. I will try the official API on monday (tuesday at the latest).
@Bob_Schor: It doesn't have to be a TTL signal like when triggering a high speed camera and a pulsed laser at PIV measurements. These have an extra input for that. I rather meant: a program which recognizes 2 GoPros and can control them simultaneously.
Unfortunately I don't know labview that well (to be honest, not at all). Is there any way (if both cameras are connected via bluetooth and it runs with Python) to synchronize the cameras with my existing measurement system?
Thanks a lot for the help and answers.
08-07-2021 06:13 AM - edited 08-07-2021 06:15 AM
If, and that’s a big IF, the GoPro API properly allows to connect more than one camera to the system and controlling them simultaneously, then I’m positive that it could be done.
But my experience with such things tells me that even the experts on this forum would need a few hours to several days to get this working and only if they have all the hardware available to test and debug it. Not everyone has a GoPro and very few more than one!
That, together with the fact that not many would be willing to spend that much time for something that they don’t somehow see useful for themselves, makes this a very difficult endeavor.