Ruben-FPV

Low-latency FPV video system using raw 802.11 packet injection. Bypasses WiFi protocol overhead (no handshakes, ACKs, retransmissions) for sub-100ms latency video transmission.

Architecture

AIR UNIT (Pi 4)                         GROUND STATION (Pi 2)
┌─────────────────┐                     ┌─────────────────┐
│  USB Camera     │                     │  Display/HDMI   │
│       │         │                     │       ▲         │
│       ▼         │                     │       │         │
│  ffmpeg H.264   │                     │  mpv/ffplay     │
│       │         │                     │       ▲         │
│       ▼         │    Raw 802.11       │       │         │
│  ruben-tx.py    │ ─────────────────►  │  ruben-rx.py    │
│       │         │    5GHz Channel     │       ▲         │
│       ▼         │                     │       │         │
│  WiFi Adapter   │ ))))))))))))))))))) │  WiFi Adapter   │
│  (Monitor Mode) │                     │  (Monitor Mode) │
└─────────────────┘                     └─────────────────┘

Quick Start - Pre-built Image (Easiest)

1. Download ruben-fpv.img from Releases
2. Flash to SD card (use Raspberry Pi Imager or dd)
3. Edit ruben.txt on boot partition:

   ROLE=air      # for transmitter (camera side)
   ROLE=ground   # for receiver (display side)
   

4. Insert SD, power on - done!

Build Your Own Image

# On any Linux machine
git clone https://github.com/rubenCodeforges/ruben-fpv.git
cd ruben-fpv/image
sudo ./build-image.sh

# Outputs: ruben-fpv.img (ready to flash)

Manual Install (on existing Pi OS)

git clone https://github.com/rubenCodeforges/ruben-fpv.git
cd ruben-fpv
sudo ./install.sh

Or one-liner:

curl -sSL https://raw.githubusercontent.com/rubenCodeforges/ruben-fpv/main/install.sh | sudo bash

Hardware Requirements

Component	Air Unit	Ground Station
SBC	Raspberry Pi 4	Raspberry Pi 2/3/4
WiFi	T2U Plus (RTL8812AU)	T2U Plus (RTL8812AU)
Camera	USB Webcam	-
Display	-	HDMI Monitor

WiFi Adapter: TP-Link Archer T2U Plus (RTL8821AU chipset) - supports monitor mode and packet injection on 5GHz.

Driver Installation

The T2U Plus requires the RTL8812AU driver (works for both RTL8812AU and RTL8821AU chips).

Pre-compiled driver included for kernel 6.12.47+rpt-rpi-v8 (Raspberry Pi OS).

# Install driver (uses pre-compiled if kernel matches, otherwise builds from source)
sudo ./drivers/install-rtl8812au.sh

# Verify
iwconfig  # Should show new wlanX interface

If your kernel differs, the script will compile from source (takes ~10 min on Pi 4, needs cooling).

Manual Usage

Air Unit

# Setup monitor mode
sudo /opt/ruben-fpv/setup-monitor.sh

# Start transmission
sudo /opt/ruben-fpv/start.sh

Ground Station

# Setup monitor mode
sudo /opt/ruben-fpv/setup-monitor.sh

# Start reception
sudo /opt/ruben-fpv/start.sh

Configuration

Edit /opt/ruben-fpv/config.sh:

WIFI_INTERFACE="wlan1"    # WiFi adapter
WIFI_CHANNEL="36"         # Must match on both units!
VIDEO_WIDTH="1280"        # Air unit only
VIDEO_HEIGHT="720"
VIDEO_FPS="30"
VIDEO_BITRATE="4M"

Service Management

# Enable auto-start
sudo systemctl enable ruben-fpv

# Start/stop
sudo systemctl start ruben-fpv
sudo systemctl stop ruben-fpv

# View logs
journalctl -u ruben-fpv -f

Troubleshooting

Issue	Solution
No monitor mode	Check iw list for "monitor" support
Driver not loading	Install RTL8812AU driver (install.sh offers this)
No video	Check camera with v4l2-ctl --list-devices
High latency	Lower bitrate, use 5GHz, check for interference
Packet loss	Move closer, check antenna, try different channel

File Structure

/opt/ruben-fpv/
├── config.sh           # Configuration
├── setup-monitor.sh    # WiFi monitor mode setup
├── start.sh            # Main launcher
├── ruben-tx.py         # (air) Packet transmitter
├── ruben-video.sh      # (air) Video encoder
├── ruben-rx.py         # (ground) Packet receiver
├── ruben-display.sh    # (ground) Video display
└── common/
    └── protocol.py     # Shared protocol definitions

License

MIT