Ear connector assignment¶

Current AW master assignment¶

The 2026-10-25 I2C routing refinement keeps the inner LED input on pin 5 and puts SCL on 6, SDA on 7. This swaps the I2C contacts from Andi's earlier manual fanout revision to remove SDA's detour around SCL's via. The subsequent below-AW transition refinement lowers C1/C5 and brings both vias below U1 for shorter, near-straight rear runs. Existing LED-only order exports still use the previous 5 SDA / 6 SCL / 7 LED_DAT2 map and retain their historical source hashes.

Ear J1 physical pin	Net/function
1	LED_DAT1: outer D1–D48
2–4	GND
5	LED_DAT2: inner D49–D69, centre last
6	SCL
7	SDA
8–10	+5V
Both MP pads	GND

The end contact gives the outer data feed a direct rear escape towards D1. The current master routes the inner input from pin 5 through bridge B; bridge A has been removed for the sensor pocket. Three contacts remain for each rail. There is no adjacent +5V/GND boundary; pins 7/8 are an SDA/+5V boundary.

The 2026-10-27 current-path target is 1.25A continuous per ear, replacing 750mA. Equal sharing would put about 417mA through each of the three supply contacts and each of the three return contacts. Check the exact FH34SRJ parts at both ends, their derating/contact sharing, the actual FFC and flex copper for drop and temperature. Parallel contacts and historical 750mA checks do not by themselves qualify the new target. This update changes requirements, not the saved connector geometry, pin assignment or frozen order inputs.

The three independent B.Cu electrodes contain covered copper-only net anchors: T1 /TOUCH_SIDE_A, T2 /TOUCH_SIDE_B and T3 /TOUCH_TOP. They are isolated from J1 and each other in physical copper. The current AW96105 schematic assigns T1 to CS4/pin 9, T3 to CS3/pin 8 and T2 to CS0/pin 7; all three feeds are routed. Each 0.8mm anchor has no coverlay or paste opening and is excluded from BOM/CPL. The former manual wire pads are removed. J1 remains the only assembled rear component. See the electrode guide; the former shared /TOUCH node is historical.

Connector pose and cable mapping¶

The source uses Hirose FH34SRJ, back-flip/dual-contact, ten contacts at 0.5mm pitch, on B.Cu: Footprints:HRS_FH34SRJ-10S-0.5SH. This supersedes the earlier FH52K/C6947686 choice and its netless hold-downs. Reconcile source value/BOM identity, actual mating thickness and local support with the selected connector before manufacture; historical library research is not a supplier acceptance record.

J1 retains its exact pose behind the former 50-LED D38/D37 (now D48/D47): (121.891384,117.490954)mm, KiCad angle -166 degrees. Viewed through the front, pin 1 is at (119.430008,116.919438)mm and pin 10 at (123.796339,115.830789)mm. The baseline has no connector notch. This pass holds Andi's current LED and connector poses. Verify entry clearance with the actual connector and cable.

The required matching headband map is 5 inner LED data / 6 SCL / 7 SDA. The 2026-10-26 headband pass applies this map to both saved band schematics and PCB, preserving all rail/LED contacts and the manually fixed socket poses. The 2026-10-26 installed-cable plan now assumes band i → ear i, with one 90° fold and the sockets the same way up. Under that assumption the band's rail/LED contacts match, and the SCL/SDA correction on 6/7 is now applied. Preserve the manually revised band connector poses. The physical continuity check remains open; the separate cross-band cable still uses 1↔10 reversal. The left ear extends I2C0 and the right ear extends I2C1; see the canonical I2C bus/address table.

These points establish the ear orientation. Actual cable continuity remains unverified. Identify actual pin 1, contact face and entry direction at both ends, then record every conductor. A straight map (band i to ear i) and reversed map (band i to ear 11-i) are different; Type A/B labels alone do not establish the installed mapping. Generate the right ear from the left master with an explicit checked map, then reconcile both ears with the band before powering an assembly.

With the same functional assignment at both ends, reversing contact order would pair 2/9 and 3/8 as GND/+5V, 1/10 as LED_DAT1/+5V, 4/7 as GND/SDA, and 5/6 as LED_DAT2/SCL. The assignment does not tolerate reversal. Adjacent-contact bridging and cable reversal are separate faults; this change reduces neighbouring supply-polarity boundaries.

User estimates: each ear FFC about 30mm; cross-band route about 170mm between frame mounts; usable band about 360mm, excluding silicone-covered end kinks. These remain fit/current/touch estimates, not a cable specification.

Previous assignments¶

Before this routing revision, pins 1–3 were +5V, 4/9/10 GND, 5/6 the same touch contacts, and 7/8 LED_DAT1/2. The preceding alternating map used +5V on 1/3/10 and GND on 2/4/9. Historical 50-LED and initial 69-LED build records retain their own maps; they are not current band/cable instructions. The historical copper-preview checks explicitly select legacy-69 rather than silently accepting either connector revision.

The 2026-10-17 electrical and geometry evidence is under build/ears/left/rear-touch-pinout-2026-10-17/. See the copper review for routing limits and checks.