Using a Raspberry Pi to add a second HDMI port to a laptop
pierre-couy.dev
A step-by-step tutorial you can follow along, featuring ffmpeg, xrandr, tcpdump and a dhcp server running on a Raspberry Pi

TLDR : My brand new laptop did not support DisplayPort over USB-C. I had a Raspberry Pi lying around unused, with its RJ45 and Ethernet ports, and I felt that I should be able to use it to bridge the gap between my laptop and my 2nd external monitor. After a lot of trial and error, I managed to get to something that I can comfortably use daily. This is a tutorial to reproduce this project in the form of a detailed writeup

I made this project a few months ago, and got some good feedback when I shared it. I also made a Github repo with scripts and config files (there is a link in the blog post), but I did not get a lot of feedback on it.

Anyway, I’d love to read your thoughts about this project.

I’m also looking for lemmy communities related to DIY tech projects and Raspberry Pis, so feel free to recommend some communities :)

  • @pcouyOPEnglish
    2•1 year ago

    Thanks for the feedback!

    I’ve tried it over my WLAN (both the Pi and laptop connected wirelessly) and the latency increases to a point where it’s not comfortable to use the keyboard and mouse with it. However it was fine for displaying htop or similar monitoring tools.

    Latency should increase even more if you use it over the internet, but the bitrate is quite low so the stream should remain fluid with reasonable latency. You should be able to encrypt the stream by looking at ffmpeg’s documentation, but I don’t know how the Raspberry Pi will handle the additional load.

    To answer your question, I used a single ethernet cable to link the laptop to the Pi both because of unencrypted traffic and latency.