Getting started on a 5.8GHz short/medium range setup

Hi Everyone !
So last week, searching for DJI FPV alternatives, I discovered OpenHD. I was thrilled !
Announced latency seems a little high for me as I’m flying mainly small quads (I have a light 6", a 4" and a 2,5"), but I’m diving into this now, betting that it can only get better. Feel free to break my expectations.

My goals are :

  1. To get a grip on OpenHD with a “simple” setup, with only the digital video link on 5.8GHz, with minimal investment (time and money).
    For this, I intend to equip my 6" quad with a Pi Zero, OV5647 Pi Zero Camera, and a TaoBao Wifi Module.
    For the GroundPi, I’ll be repurposing a Pi 3B and another TaoBao module

  2. When I succeed at goal #1, I intend to push the project further, to achieve something like this : https://www.youtube.com/watch?v=BEfj799LDbI
    (Digital FPV with headtracking on a 1100mm plane, for aerobatics. In this video, the guy uses DJI Goggles Race Edition)

I have a few questions :

  • I’ve just bought FPV Goggles with 1280*960 screen resolution (Sky04x with HDMI input). Will a Pi Zero on the Air side and a 3B on the ground side be able to stream at a suitable data rate to match that native resolution ?
  • I’d like to keep my 2.4Ghz Frsky setup for RC control. Will I still be able to use the OSD ?

Yep you’re all set I think, you can stream 1080p30 and even turn the bitrate up a bit if you need to.

Your RC setup will work alongside 5.8ghz video, however if you see interference with the video (turn the TX on and off to prove it) you may consider 868/900mhz, several others are doing that at the moment.

Thanks for your answer Stephen !
And what about the OSD ? I mean if I link the AirPi to my flight controller (F405), will the data such as Voltage or Amps get to the GroundPi alongside the video stream on the digital link ?

Another question : If I have some headroom as you seem to imply, will lowering the definition help to get lower latency somehow ?

Yep OSD will work the way you expect.

Latency on the pi is primarily affected by the framerate setting, on the picam v2 people have tested it at ~85-90ms if the framerate is turned up high enough. The zero cam can do 720p48 or 480p60.

If you’re in need of very tight control the latency may still be a bit high, but try it, carefully :slight_smile:

There are other boards that we’re about to release support for that can produce lower latency depending on the camera sensor and the settings, and future custom hardware development (not in the immediate future, a few months) is likely to reduce that even further.

There are other boards that we’re about to release support for that can produce lower latency depending on the camera sensor and the settings, and future custom hardware development (not in the immediate future, a few months) is likely to reduce that even further.

Other boards => The Jetson Nano I presume ?
Future custom hardware development ? Cool !
And a few months, in my today’s life (with 2 little girls and almost no hobby time) is like tomorrow ! :grin:

Hi !
I wish to report a complete success with my first setup.
It just worked perfectly out of the box, which is (to me, at least) no small feat.

What wifi cards are you using? And what range do you get?

I’m using the TaoBao 5.8G cards.
I couldn’t check range, it was a bench build.

Could you please share the link of your WiFi cards?
My setup is not working out of the box as I had expected :(, I don’t mind trying different cards.

Here it is :

Unfortunately it seems to be out of stock at the moment.

hi,

as anyone tested or used this wifi card for openHD setup with Pi4b: