A wearable 64×64 LED field that renders the radio environment around you as living, interactive weather. Built for DEF CON 34 — one of the densest and least predictable RF environments you could build for.
About rF Backpack
You are swimming in radio right now. Hundreds of access points, phones advertising themselves, handhelds keying up, badges chirping — an entire invisible weather system, and you have no sense organ for any of it.
The rF Backpack gives you one for a moment. A 64×64 LED panel on the back of the pack runs a real-time fluid simulation fed by the actual RF environment: WiFi and Bluetooth activity becomes smoke, dye, and light. New sources bubble in as glyphs and dissolve into the field. Motion stirs it — walk and the fluid pours around you, tilt and it pools downhill, set the pack down hard and the whole thing shakes like a snow globe.
Everyone else’s LED backpack talks. This one listens.
Nothing on the panel is canned. What you’re seeing is the room, right now, rendered as weather.
It’s art informed by engineering. Not a product, not a demo, not for sale — an excuse to build something hard, and an invitation to play.
- 64×64 RGB LED matrix — 4,096 pixels of real-time fluid simulation
- Passive WiFi, Bluetooth LE, and sub-GHz spectrum sensing
- 6-axis IMU — the pack knows how it’s moving and the fluid responds
- Raspberry Pi + Teensy 4.1 render pipeline at a solid 30 fps
- Battery powered, fully self-contained, needs no network — ever
The rF Backpack doesn’t tell you what devices are around you. It gives the room a weather system. The invisible activity everyone at DEF CON is already creating becomes something everyone nearby can see, disturb, and play with.
How to Play
You don’t need an app, badge, or instructions. If you’re carrying a transmitter — and at DEF CON, you are — you’re already part of the piece.
Just watch.
Every new WiFi or Bluetooth source that appears nearby announces itself with a glyph, then melts into the field as colored dye. Green is WiFi. Blue is Bluetooth. The field is the room.
Key up.
Transmit near the pack and watch the field react. Probe storms, repeated transmissions, bursts of RF activity — it’s all weather here. Blast it repeatedly and the piece armors up, making each blast cost more than the last. Go ahead. It’s designed to be attacked.
Move.
The wearer’s motion drives the simulation — walking, tilting, and a hard thump each do something different. Deliberately roll the pack and it steps through display modes: ambient field, walking view, tabletop sonar, chunky QR, and more.
No explanation required. If it only worked when explained, it wouldn’t work.
Features
- Real-time WiFi source visualization (fully passive — it never transmits)
- Bluetooth LE device discovery, rendered as living dye
- Sub-GHz spectrum sweeps via SDR
- Motion-reactive: walk, tilt, and thump interactions via onboard IMU
- Multiple display modes with motion-based switching
- Snow-globe shake, arrival glyphs, and shockwave effects
- Chunky on-panel QR code — scan the pack to reach this page
- Blackbox flight recorder — sanitized simulation events and state can be replayed deterministically for debugging and tuning
- Battery powered, fully self-contained, zero network dependency
- Built to be poked, questioned, attacked, and improved
Ground Rules
One hard line, by design: the pack visualizes activity, never identity.
- No cameras. Ever.
- No MAC addresses, device names, or fingerprints — on screen or on disk
- Source IDs are salted and opaque, regenerated every boot
- Nothing about any individual is displayed, tracked, or retained
A deauth flood shows up as weather, not as “attack detected.” The piece isn’t judging, identifying, or defending against anything it sees. It’s watching people play — and letting everyone else watch too.
Have Questions, Ideas, or Want to Collaborate?
The rF Backpack is a living project, and the best ideas so far have come from conversations at the con. If you saw it in the wild, want to build something like it, or want to talk RF art — reach out.
- Email rFBackpack@proton.me
- Web groplot.com