See project on github!

Oscilloscope as webcam

Video-chat with your Oscilloscope. Seriously.

I own a Rigol DS1054Z Oscilloscope and needed to capture the screen for a project.

I found articles from theimpossiblecode and hackaday with instructions for capturing still images (screenshots) of the scope, but I need video!

Setup

First connect the scope to your network with an ethernet cable.

Next enter the Utility > IO Setting > LAN Conf. menu and set a static ip address. For my network I choose 192.168.0.10.

Check you can connect to the scope from your computer.

$ ping 192.168.0.10

Install the required software for your distribution.

$ sudo apt install v4l2loopback-dkms v4l2loopback-utils ffmpeg imagemagick

Finally, enable v4l2loopback and set the framerate.

$ sudo modprobe v4l2loopback
$ v4l2loopback-ctl set-fps 24 /dev/video1

Usage

Ok, here’s the good part. Run this command:

while true; do
    mogrify -format jpg | \
    echo ':display:data?' | \
    netcat -q 0 192.168.0.10 5555 | \
    tail -c +12 | \
    ffmpeg -re -i pipe: -f v4l2 -vcodec rawvideo -pix_fmt yuv420p /dev/video1
done

Here’s what that does:

1. netcat establishes a tcp connection to the scope on port 5555.
2. The message :display:data? is sent. This requests the current display data (screenshot) from the scope. The screenshot is returned as a bitmap with a 12 byte header.
3. The 12 byte header is removed removed.
4. The bmp image is piped to the imagemagick “mogrify” program to convert the bitmap to a jpg.
5. Finally the jpg frame is piped to ffmpeg that writes the frame to /dev/video1.
6. repeat.

Framerate? netcat is grabbing frames as fast as the scope can send them, but each frame is 1.2MB! For 30fps video this would take 1.2M*30= 36MB/s = 288 mbps! The ethernet port on this scope is 100mbps so the output video is limited to ~10 fps 1.2M*10= 12MB/s = 96 mbps under perfect network conditions.

That said - if you’re ok with 10 fps video. Good news! This device is recognized as a regular video device. You can treat it like a webcam! Usable with OBS, heck you can even video-chat with your O-scope.