Sensing
Per-channel envelopes, aggregate rate, and the on-body/off-body compute split
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This is the primary axis: the body exists to acquire physical experience. Quantifying it forces a question that a single multiplier cannot answer.
5.1 "× human" is not one number — it is five axes
"As sensitive as human skin, times N" decomposes into five independent quantities, and they do not all move together:
| Axis | Human | Can it exceed human |
|---|---|---|
| Point density | ~241 mechanoreceptors/cm² at the fingertip (sourced) | No — see below |
| Sensitivity threshold | — | Yes, substantially |
| Temporal bandwidth | Pacinian corpuscles to ~500 Hz | Yes — piezoelectric sensors reach tens of kHz ⇒ 20–100× |
| Dynamic range | finite, saturates early | Yes |
| Simultaneous modalities | pressure, vibration, temperature, pain | Yes — the self-healing layer of 04.2 also senses pH and humidity |
Density is blocked twice, independently:
- Fabrication. The densest published e-skin array reaches ~347 elements/cm² (sourced) — roughly level with human skin, not above it. A 100× density means 24,100/cm², about 69× beyond anything yet built.
- Bandwidth. Even if it could be built: 24,100/cm² over 1.6 m² is 386 million points. At 1 kHz and 12 bits that is ~4,600 Gbps of tactile data alone — 580× the 8 Gbps link of 01. No compression ratio rescues that.
Declared tactile capability: density level with human skin in the fine regions (hands, face), thinning across the torso; 20–100× human in temporal bandwidth; above human in sensitivity threshold, dynamic range, and number of simultaneously measured quantities.
5.2 Tactile layout
Uniform whole-body density is wasteful — human skin is not uniform either.
| Region | Area | Density | Points |
|---|---|---|---|
| Fine — hands, face | ~500 cm² | ~300/cm² (near the fabrication ceiling) | ~150,000 |
| Ordinary — remainder | ~15,500 cm² | ~20/cm² | ~310,000 |
| Total | 1.6 m² | — | ~460,000 |
At 1 kHz and 12 bits: 5.5 Gbps raw — two thirds of the link, from one channel. (1.8 m², ~500,000 points and 6.0 Gbps until the height came to 1.65 m on 2026-09-26.)
5.3 Channels
| Channel | Anchor configuration | Raw rate | Note |
|---|---|---|---|
| Stereo vision | 2 × 4K, 30 fps, 12 bit | 5.97 Gbps | Optical zoom, multispectral, thermal IR retained |
| Thermal IR | 640×480, 30 fps, 16 bit | 0.15 Gbps | |
| LiDAR / depth | 300k points/s | 0.04 Gbps | |
| Microphone array | 16 ch, 48 kHz, 24 bit | 0.02 Gbps | High-sensitivity, directional |
| Proprioception | 41 joints × 4 channels + IMU, 1 kHz | 0.006 Gbps | Joint count declared at hardware/kinematics.md. Cheapest channel, and the one that must not be cut — see 5.5 |
| SDR / multi-band RF | 2 ch × 56 MHz I/Q, 16 bit | 3.58 Gbps | |
| Spatial RF sensing | Wi-Fi / mmWave CSI | modest | Retained at full hardware capability; use is ⟦CTRL⟧ |
| Olfaction (e-nose) | — | negligible | 5–30 ppb achieved per compound (sourced); 5–10 s response |
| Taste (lab-on-chip) | — | negligible | Slow, batch-wise |
| Trajectory prediction | ~1.5 s horizon | — | Computer vision plus human trajectory prediction. TM |
| Voice and ultrasound | — | — | Synthesis plus ultrasonic emission. TM |
| Biological response | pupil, expression | — | Micro facial actuators and microfluidics. TM/LAB |
| Cardiac co-regulation | vibration, warmth, rhythm | — | Optional module, not always-on. Instrumented per 06.6 |
On olfaction. Parts-per-billion thresholds are achieved. What has to be reduced is not sensitivity but sensitivity × breadth of compounds × speed simultaneously: a sensor reaching 5 ppb for one compound takes 5–10 seconds, and no array reaches ppb across hundreds of compounds in real time.
5.4 Aggregate rate against the link
| Configuration | Vision | Tactile | SDR | Total | Minimum compression |
|---|---|---|---|---|---|
| A — conservative (4K30, 460k points) | 5.97 | 5.52 | 3.58 | 15.1 Gbps | 2 : 1 |
| B — moderate (8K60, 1M points, 4-ch SDR) | 47.8 | 12.0 | 7.17 | 67.2 Gbps | 8 : 1 |
| C — 100× density | 47.8 | 5,206 | 7.17 | 5,261 Gbps | 658 : 1 — excluded |
Available link: 8 Gbps.
The on-board / off-board split of 01 is not a design preference. It falls short by 2× in the most conservative configuration and by 8× in a sensible one. On-body processing is arithmetic, not taste.
5.5 Proprioception is mandatory
Joint encoders, IMU and force/torque sensing, dense enough to distinguish "I just moved" from "something moved me".
This is the cheapest channel on the list and the one that cannot be omitted. Two separate requirements land on it:
- Experience. A touch from another person must be cleanly separable from the body's own motion, or the experience being acquired is corrupted at source.
- The platform contract. An external processing loop requires that every change be classified as self-caused or not before it is interpreted — see 08. Without adequate proprioceptive hardware that requirement cannot be enforced, and every layer above it reads wrong.
The same hardware serves a third purpose in 06.3.
5.6 The on-body / off-body compute split
What is split here is processing, not decision. Deciding is the Main Controller's, off the body (01); the dial sets how much of the processing — compression, feature extraction, fusion — runs on the unit.
The split is a dial with two hard ends and a soft middle.
Lower end — what must be on the body:
| Constraint | Figure |
|---|---|
| Minimum compression | 2 : 1 → 8 : 1 (5.4) |
| Balance loop | ≥ 500 Hz |
| Fast reaction loop | ≤ 10 ms |
| Context record for every output event (RSIL INV-8: anchored context on every emission) | per event (08.2) |
Link round-trip is ~1 ms at ideal short range, but at kilometre range with beam tracking it cannot be relied on for ≤10 ms. Balance and reflex are therefore on-body — not because the design prefers it, but because there is no alternative.
Upper end — what must not be on the body:
| Constraint | Content |
|---|---|
| Losing a unit loses its state | Its own state and its unsynchronised record, never memory; the more processing on the unit, the more of that there is (01) |
| Power | Edge compute draws on the same p (W/kg) that enters the convergence condition Σf < 1 |
| Heat | A sealed body in human contact dissipates worse than a rack |
| Memory and world model | Off-body by architectural definition, not by capacity |
Edge compute is not "add as much as you like, it only costs battery." It eats into the convergence condition of the whole body, and 02.3 shows
γinflating non-linearly near the ceiling.The middle — feature extraction, compression, predictive modelling, tracking of other agents — is
⟦CTRL⟧, and should be adjustable per mission rather than a compile-time constant.
Operating point: ⟦CTRL⟧.