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Show HN: Send me an IRL message and watch it arrive (hi.benren.au)

41 points by GSGBen ↗ HN
- This page is running directly on the Pico W in the stream, using microdot (but proxied out via cloudflare tunnel).

- There's a buzzer that plays a sound as well but the stream has no audio.

- There's a Pi Zero 2 W with a Camera Module 3 streaming the video. Streaming low latency video is painful. I tried mjpeg, Nginx+HLS/DASH, YouTube and Twitch. Twitch is definitely the easiest and best-performing.

- There's still a few seconds delay between sending your message and the video updating.

20 comments

[ 3.1 ms ] story [ 57.2 ms ] thread
forgotthetimer
(OP, temp user, forgot to disable the HN procrastination timer)

For anyone trying to do this in the future, here's the command to stream from a modern Pi camera module / driver to twitch. IIRC I also had to install the full version of the libcamera tools to use the libav switches.

    libcamera-vid -v 0 -t 0 --codec libav --libav-format flv -o "rtmp://<twitch stream url>/<twitch stream key>" --rotation 180 --width 1920 --height 1080 --framerate 30 --bitrate 4000000 --autofocus-mode auto --autofocus-window 0.25,0.15,0.5,0.5
forgotthetimer
Update: there's been a bunch of great messages so far, from people all over. But most importantly we've had a

    ');DROP TABLES;
scrps
Make a few model tables and have a lever on a servo push the tables off the desk upon DROP TABLES.
GSGBen
Update 2: The servo's gears are absolutely grinding at the moment
jbit
Check out the `--shutter` option for `libcamera-vid`, it allows you to tweak the camera's exposure time which might help with the screen refresh banding. `--shutter 60` sets the exposure time to 60ms, which might be a good starting point.

EDIT: Ah, actually the unit is microseconds, so `60000` would be 60ms

GSGBen
Hey thanks, this was a good catch. `--shutter 12000` fixes the screen, and is bright but not too bright.
gus_massa
Should I see in the video the text that I had sent?

I see only the hand moving.

forgotthetimer
Yep, it should show on the screen but unfortunately the camera refresh rate is out of sync with the screen's refresh rate so it's a bit hard to see. I need to read the datasheet again and drop the screen's refresh rate - I tried adjusting the camera's instead but it was never quite right.
gus_massa
Can you cheat and just repeat the same letter a few times, like "Hello!!!" -> "HHHeeellllllooo!!!" or it shows a dark frame between leters?
forgotthetimer
Getting the data onto the screen is fine, and IRL I can't see any flicker, but the OLED screen itself is apparently refreshing at something like 107 or 133 Hz.
liminalsunset
One way to potentially resolve this is to place the setup in a darker place and/or add a piece of tinted transparent material in front of the camera. The camera will automatically adjust the shutter speed (not the frame rate) because of the reduced light to 1/30 or so which will allow more of the screen to be captured.
tamimio
Ah, just seen your comment, try to use obs and adjust the rate from there before streaming it.
tamimio
I send it and only partial parts showed, I think the camera recording the steam is on a different Hz than the screen, out of sync, could not see it properly.
globalnode
your other game project 'grab n throw' looks hilarious, what made you think of that? its like a funny 3d version of pong (without stuff coming back)
GSGBen
Hey, thanks! I was thinking about game ideas while stepping into the shower one day (where all great ideas are born), and "throwing people in a first-person view might be fun?" came across my mind. I mentally fleshed it out a bit, and wrote it down. When the idea I was already working on turned out to not be fun, I shelved that and started working on this instead. When I prototyped the basic throw feel and it already felt fun, I decided to run with it.
globalnode
having them fall down with all that ragdoll physics is the best part, also crashing into crowds like bowling balls. anyway, best of luck with it all, seems like a really original and entertaining idea.
vachina
You need to increase the camera’s exposure time (integration time) and decrease the ISO. Could barely see the screen.
averageRoyalty
Ooh, a .au. Don't see them often in the wild.

Down now, but sounded interesting!