Changelog

0.4.0, 2026-11-02

The line follows volume, and the approved size direction.

Layouts by volume (decision 25; nplusonelabs/factory #21 at 9bc6753). Three new variants:
- A one-technician bench cell for the first 100 builder units, now the recommended layout.
- A two-person U cell for about 2,000 to 4,500 a month.
- A seven-person balanced line on the MadeCell base (decision 24) for about 10,000 a month.
line/layouts/ holds the three layout files and a README. media/line/yamazumi-by-volume.svg charts station times against takt. Capacities are simulated from assumed values, uncalibrated; takts come from the assumed demand.
Battery tug check 3 N, up from 2 N. In the factory simulation a 2 N tug let half-seated plugs through. The operation, the control plan and the PFMEA row are updated.
Station equipment follows the factory build spec. S1 gets a hot-air cold staker with six nozzles and a punch-travel monitor. S3 gets a torque arm and a screw presenter. S7 gets an acoustic box at 94 dB SPL, 1 kHz, and a six-face tilt table.
Approved size direction: about 55.4 mm across and at most 12 mm thick. This replaces 57 x 9.5 mm in the design targets. The CAD, the magnet ring, the lugs and plus-one-base@1 still need rework, so they're unchanged here.
New sources: the factory engine, the layout study, decisions 24 and 25, and the dimension direction.

Moves to OPD 0.5.0. Trust level claimed, the new name for draft. No values changed.

Accessories.

accessories/: a README for builders, interface.yaml with the base as an interface (plus-one-base@1), a catalog of five first-party accessories and the free printables, a printable fit gauge, a flat back template, the steel ring, and a parametric template script.
The rim now has three windows that expose the lugs, so a back's hooks can twist under them without adding thickness or width. The key slot is an arc, so the key guides the twist.
Proposed: a pad pinout (PWR, SDA, GND, SCL, ID) and a 1-Wire accessory ID record.

Generation one, per decision 20.

Phone-ring size: about 57 mm across and 9.5 mm thick, down from 58 x 19 mm. The cell, module, speaker and haptic now sit side by side under the board. The stack-up is in the design brief, with 8 mm left as an open question.
One base, any back. The base carries a magnet ring, three twist-lock lugs inside the rim, an alignment key and five pogo pads outside the charging coil. The two base magnets and the flat foot back are gone; nothing ships attached.
Wireless charging on every unit: a receiver, coil and ferrite inside the magnet ring. The cell is about 150 mAh (target).
S6 now bonds the magnet ring and places the coil and pads. S8 tests wireless charging and packs no back. S8 is 56 s against a 60 s takt.
New PFMEA rows for ring polarity, coil offset and recessed pads. New design targets for magnetic hold and lug pull-out.
A wearable generation two (about 40 to 44 mm) is noted as what's next, outside this OPD.

First release of the Plus One OPD. OPD 0.4.0, trust level draft, prototype in design.

Card, build card and design brief.
37 parts with STEP and GLB CAD for every mechanical part, an assembled and an exploded model, and a USD scene.
BOM without prices, likely suppliers, electronics detail.
19 operations on an 8-station line, with SOPs, sampling plans, 14 tests and a control plan.
10 PFMEA rows, three of them carried over from the EC-1 lessons.
A variant study: splitting S8, and Plus One+ and Plus One++ as coming next.
A draft device model under proposal 0001.