An audible relay and grid-search simulation for a 42 × 32 flat grid, with four conceptual flight-depth bands. The 48-second demonstration circulates through nested rectangular search paths, transmits cell acknowledgments as audible data, and retries missing records before declaring coverage complete.
Watch the video · Download the lossless audio · Read the protocol
Open index.html in a modern browser and select Play with sound. The page generates its own audio locally and has no external script dependencies. Sound can be muted, and playback can be paused and resumed.
To serve the repository locally:
python3 -m http.server 8000Then open http://localhost:8000.
- 1,344 distinct grid cells per depth band, or 5,376 cell-band records.
- Sixteen nested rectangular circuits. D0 and D2 scan inward; D1 and D3 reverse the route and scan outward.
- Four logical relay nodes with a clockwise handoff order: R1 → R2 → R3 → R4 → R1.
- 1,200-bit/s audible binary FSK, using 1,200 Hz for zero and 2,200 Hz for one.
- Depth tones at 440, 554.365, 659.255, and 880 Hz, with acknowledgment clicks during repair.
- 200 encoded packets: 168 initial reports and 32 repair reports. All decode successfully from both the supplied WAV and MP4.
The scan deliberately leaves eight acknowledgments missing in each band. Coverage reaches 5,376 only after the repair phase confirms those 32 records.
Use Python 3.10 or newer, the packages in requirements.txt, and FFmpeg on your command path.
python3 -m venv .venv
. .venv/bin/activate
python -m pip install -r requirements.txt
python scripts/build_transhopper.py
python scripts/render_transhopper.py
python scripts/verify_media.py
python scripts/verify_media.py --videoThe builder writes media/transhopper-audio.wav and media/manifest.json, and checks its synthesized audio by decoding every packet. The renderer writes media/Transhopper-42x32.mp4 and media/preview.png.
The renderer defaults to the DejaVu Sans and DejaVu Sans Mono files in /usr/share/fonts/truetype/dejavu/. On other systems, set TRANSHOPPER_FONT and TRANSHOPPER_MONO_FONT to installed font-file paths.
This is a deterministic concept demonstration. Grid dimensions and depth bands have no assigned geographic distance or altitude. The recording is an accelerated visualization of a logical scan, not a helicopter flight plan.
Acknowledged coverage does not establish detection of every physical signal. Sensor footprints, noise, terrain, dwell time, and real radio transport are outside the model. Relay membership, actual network delivery, authentication, duplicate suppression, and hop-limit enforcement are not implemented. The hop-limit field is reserved for a future forwarding implementation.
Apache License 2.0. See LICENSE.