Library document
The Adapter Inventory
The legend, the band-by-band translator table across the frequency axis, and the ranked gap analysis, showing where a translator is still missing and which gaps are worth closing.
The legend and map of adapters across the frequency axis. Read alongside the Principles. Tags: ESTABLISHED FRAMING OPEN CONTESTED CLOSED.
Part 1: The Legend (how to read the map)
The axis. One continuous logarithmic frequency axis, in hertz, from a practical sub-hertz floor to the Planck-frequency region. Everything we sense, build, or compute sits along it.
The law, not the axis, is the unifier. Every entry obeys E = ħω: a quantum carries energy in proportion to its frequency, by the same constant across substrates. ESTABLISHED The axis lines the bands up; the law makes them one family. (See Principles, Principle 5.)
An adapter is a translator. Every entry is a device or organ that converts a vibration in one band into another form, either into a human sense directly or into something a machine can read and then hand to a sense. A working adapter is a proof that the two forms were the same thing in different vocabularies.
The gap is the product. Where an input or output adapter is missing, costly, or lab-bound, that cell is a frontier: a synonym we suspect but have not yet proven. Part 3 ranks them.
Part 2: The Adapter Inventory
A. Electromagnetic band (the photon line)
| Band | Freq (approx) | Native human sense? | Input adapters (sense/read) | Output adapters (emit/write) | Status |
|---|---|---|---|---|---|
| ELF / ULF | 3 Hz – 3 kHz | No | Induction coils, fluxgate & SQUID magnetometers, MEG | Sub-sea ELF transmitters (km antennas), coils | Thin; bulky, no consumer adapter OPEN |
| Radio (LF–EHF) | 3 kHz – 300 GHz | No | Antenna + receiver, software-defined radio | Transmitters of every kind | Saturated, the most-built band ESTABLISHED |
| Terahertz | 0.1 – 10 THz | No | THz time-domain spectrometers, bolometers (lab, costly) | Quantum-cascade lasers (emerging) | Major gap, no consumer adapter OPEN |
| Infrared | 10 – 400 THz | Crudely (skin feels thermal IR) | Thermal cameras, bolometers, IR photodiodes, fiber detectors | IR LEDs, IR lasers, heaters | Good but pricey at the imaging end ESTABLISHED |
| Visible | 400 – 790 THz | Yes (eyes) | Cameras, image sensors | Displays, lasers, lighting | Saturated ESTABLISHED |
| Ultraviolet | 0.8 – 30 PHz | No (and harmful) | UV sensors and cameras | UV LEDs, lamps, lithography sources | Built, consumer-rare ESTABLISHED |
| X-ray | 30 PHz – 30 EHz | No | Scintillators, flat-panel detectors | X-ray tubes | Clinical/industrial only, no personal adapter OPEN |
| Gamma | > 30 EHz | No | Scintillators, Geiger counters, semiconductor detectors | Radioisotopes, linacs | Specialized only ESTABLISHED |
B. Mechanical / acoustic band (the phonon line)
| Band | Freq | Native human sense? | Input adapters | Output adapters | Status |
|---|---|---|---|---|---|
| Infrasound | < 20 Hz | No (sometimes felt as unease) | Infrasound mics, seismometers, barometric sensors | Subwoofers, seismic shakers | No personal "infrasound sense" device OPEN |
| Audible | 20 Hz – 20 kHz | Yes (ears) | Microphones | Speakers | Saturated ESTABLISHED |
| Ultrasound | 20 kHz – ~GHz | No | Ultrasonic rangefinders, medical ultrasound, SONAR | Ultrasonic transducers, mid-air ultrasound haptics | Built; personal spatial-sense aids are nascent OPEN |
C. Other channels that share E = ħω but lack infrastructure
| Channel | Freq / regime | Input adapters | Output adapters | Status |
|---|---|---|---|---|
| Gravitational waves | nHz – kHz | LIGO/Virgo (10 Hz–kHz), pulsar-timing arrays (nHz), LISA (mHz, future) | None feasible | Detection only; the interplay is too weak to convert into OPEN |
| Neutrinos | n/a (particle, not a band) | Cubic-km detectors (IceCube), reactor/solar detectors | None practical | Enormous gap; mostly not addressable with present physics OPEN |
| Static / geomagnetic field | DC – sub-Hz | Magnetometers, compasses | Electromagnets | Sensing mature; wearable field-to-sense translators are experimental OPEN |
| Spin resonance (NMR/ESR) | RF coupled to spins in a field | MRI, NMR, ESR spectrometers | RF coils + gradient fields | Clinical/lab only, no consumer adapter OPEN |
| Molecular vibration (IR/Raman) | THz – IR | Lab spectrometers; handheld "molecular sensors" (nascent) | Tunable IR/Raman sources | Cheap handheld "see-the-chemistry" adapter is missing OPEN |
| Biopotentials (ECG/EEG/EMG) | sub-Hz – kHz | Electrodes, BCIs | Neuro/muscle stimulation | Input mature; closed-loop write-back growing OPEN |
Part 3: Gap Analysis, where to spend the time
Priority ≈ (gap size) × (human value) × (tractability now). Ranked:
-
Sensory-substitution wearables: route an imperceptible band into a sense we already have. OPEN Magnetic field → haptic, thermal IR → visual overlay, ultrasound → spatial sense, infrasound → haptic. The brain is plastic about its inputs; the engineering (haptic arrays, bone conduction, AR overlays, low-power sensors) exists today. This is the most direct adapter, the translator worn on the body.
-
Compact, affordable terahertz adapters. OPEN The classic "THz gap." High value across security imaging, non-destructive material ID, medical, and 6G. Sources and detectors are maturing, and a consumer-grade THz imager is a real frontier.
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Handheld molecular (IR-Raman) sensing, "see chemistry." OPEN Spectrometers exist but are lab-bound. A cheap adapter that reads molecular vibration fingerprints (food freshness, materials, contaminants) maps onto an empty consumer cell.
-
Personal X-ray-class and magnetic imaging. OPEN Detectors exist but are clinical. Lower-dose, lower-cost, safety-bounded personal adapters are a long-horizon target with obvious value.
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Output adapters for the detection-only channels. OPEN We can detect gravitational waves and neutrinos but cannot emit them. Honest note: these are largely not addressable with current physics, so mark them as boundaries (Principle 4's "real seam"), not quick wins.
-
The translation layer between vocabularies, including in machines. OPEN The richest unexplored region is not a band at all. It is the work of proving that two differently-named things are one: cross-substrate transduction in physics, and schema/ontology translation in software and AI, where the same fragmentation multiplies the walls. (See Principles, Principle 6.)
Part 4: The map's edges (heuristic, not surveyed)
Two rough bounds, marked as framing rather than hard walls:
- Lower edge: a wave longer than the observable universe (~10⁻¹⁸ Hz) leaves no room for one cycle, so as a practical matter there is nothing to build below it. FRAMING
- Upper edge, the Planck-frequency region (~1.85 × 10⁴³ Hz): by the standard back-of-envelope reckoning, a single quantum there would carry enough energy to collapse into a black hole, and known physics stops describing what lies beyond. Treat it as a working boundary, not a surveyed one. FRAMING
Between the edges the spectrum is continuous: there is no frequency at which a wave cannot exist. So the real gaps are never holes in reality; they are missing adapters. That is why the project is tractable: for most of the map we are not waiting on new physics, only on new translators.
See Sources for the citations behind the settled claims.