Using 3 of the Low Light Cameras with one Ras pie 4

Build MATE ROV
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Hi, I have been reading through the forums and haven’t gotten a clear answer, but I was wondering if it is possible to use three or even four of Blue Robotics cameras on a single Ras Pie, and if it is what are the steps to setting a system like that up? Also is it possible to split screen it? Sorry if this question has been already answered.

Sincerely,
Levi Rumohr

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Hi @LeviRumohr15, welcome to the forum :slight_smile:

Using BlueOS you can easily set up multiple streams (just configure them in the Video page), and there are some options covered here for receiving them. The main limitations with extra cameras are

  • bandwidth usage (can be problematic over a long tether)
  • decoding at the topside computer (may require a lot of processing power, depending on resolution and frame rate)
  • port availability (a Raspberry Pi has 4 USB ports, and in our vehicles one of those is generally taken up by the Pixhawk flight controller, and others are frequently used by other peripherals like sonars)
    • it may be possible to work around this with a powered USB hub to one of the USB-3 ports on the RPi 4, although with lots of peripherals you’ll need to take extra care to avoid the electronics in the enclosure overheating
1 Like
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Thank you!
I just have a few final notes, first off the way our system is built the motors are run off of a separate system (we are using Thruster Commanders), so the RPi is for the cameras alone which I believe solves the problem for the extra peripherals (let me know if I’m wrong here or if that won’t work). Second, lets say we dropped two of the cameras and only used two instead of four, would that still cause significant bandwidth issues? Finally, is it possible to send the camera feed up from the RPi via ethernet? Thank you for your awesome support!

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Hello!

We have written documentation on this exact setup actually, you can read it here:

This will work the same for any H264 USB Cameras. We are also currently working on a UI to adjust bitrate. It should work for most H264 USB cameras as well.

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We will let you know when that is finished.

Hope that helps!

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That should be fine :slight_smile:

It’s possible that even 4 cameras would be fine, it depends on your connection. The point is more that more cameras → more bandwidth required, so if you’ve got a low bandwidth connection then you won’t be able to use as many cameras :slight_smile:

Yes, although it depends a bit what you mean:

  • On the software side, that’s what BlueOS’s streaming functionality does, once it’s installed it’s as simple as going to the Video tab and turning on/configuring the streams you want.
  • On the hardware side, what you use depends on your length/distance requirements.
    • For short distances it could be fine to just use a cat5e cable directly from the Raspberry Pi to the topside, although then it may be challenging to get a signal to your thruster commanders, and it can be difficult to get an ethernet attachment/connector inside the enclosure.
    • For longer distances you’ll need to use something like our Fathom-X boards, which transport an ethernet signal through a single twisted pair, in which case other twisted pairs in a multi-pair tether (like our Fathom Tether) could be used for controlling the thruster commander(s)