L'Atelier

Engineering dossier for Le Pinson

Le Pinson is a titanium cuff with a voice assistant. It is made of two parts: a solid titanium cuff that the owner keeps for life, and the stone itself: a sealed jewel module that holds all the electronics and lifts out of the cuff to be replaced every few years.

Research date 22 October 2026 · Prices in USD unless marked · Internal working document, not for publication.

V checked on a manufacturer or distributor pageest our estimateTC to confirm with the supplier

In one minute

Two parts. A permanent titanium cuff with no electronics, and a replaceable stone module (“Le Calibre”): the long black sapphire in its titanium bezel, with all the electronics in a small capsule hidden underneath.
It looks like one jewel. The capsule sits in an oval cup machined into the top of the cuff; only the bezel and the stone show, 6.5 mm from skin to the top of the stone est.
One module fits every cuff. All cuff sizes and finishes share the same oval cup. Owners can have several cuffs and one stone.
Attachment: magnets seat the stone, a hidden spring latch locks it. To remove it, press a small pin through a hole on the skin side of the cuff, then lift the stone out.
Battery, the honest number: the stone-only module holds a ≈ 25–30 mAh cell, about 3 days of typical use and 6 days of light use est. Option B extends the hidden body under the band to ≈ 48 mm for ≈ 50–60 mAh and about 6 days est. We prototype both.
Size and weight: bezel 36 × 12 mm, stone 34 × 10 mm, capsule 35 × 11 × 4.0 mm; module ≈ 4.3 g, whole piece ≈ 23–25 g est.
Business model: one titanium set at ≈ CHF 349, below the price of an Apple Watch. A new stone module every 3–4 years with a trade-in. Programme ≈ 20–26 months; funding ≈ CHF 5–7.5M to the first customer and ≈ CHF 12–18M over three rounds est (section 13).

Stone module

36 × 12 mm

bezel; capsule 35 × 11 × 4.0 mm below est

Skin to stone

≈ 6.5 mm

cuff 5.0 mm at the cup, 2.4 mm in the arms est

Battery life

≈ 3 days

typical, stone-only; ≈ 6 d with Option B est

Weight

≈ 23–25 g

cuff ≈ 19–20 g + module ≈ 4.3 g est

Suggested price

CHF 349

cuff + stone module + dock; range CHF 299–399; upgrade CHF 129–149 est

Programme

20–26 months

≈ CHF 5–7.5M to first customer, ≈ CHF 12–18M to break-even est

What it looks like

Key point

A slim titanium cuff with one long oval black stone in a gold-tone titanium rim. The stone is the module: all the electronics sit in a hidden capsule under it, and it lifts out of its seat to be charged, serviced or upgraded.

Render of the titanium cuff with the long oval black stone in a gold-tone titanium rim — Renders made with an image model from the to-scale drawing in 4.0 and the reference design. Proportions follow the drawing; textures, light and exact details (such as where the contacts sit) are illustrative.

Render of the cuff worn on a woman's wrist — Renders made with an image model from the to-scale drawing in 4.0 and the reference design. Proportions follow the drawing; textures, light and exact details (such as where the contacts sit) are illustrative.

01The concept: permanent cuff, replaceable module

Key point

The jewellery and the electronics have different lifetimes, so they are separate objects. The cuff lasts decades; the module is upgraded every 3–4 years.

Part	What it contains	Expected life	Service
Cuff	Solid Grade 23 titanium, sizes S–XL, with an oval cup machined into the top. No electronics, no battery, no seals. Natural titanium; black as a second finish later.	Decades	Refinishing service
Stone module (“Le Calibre”)	The titanium bezel and black sapphire you see, plus a hidden capsule with the chip and radio, 2 microphones, memory, power chip, accelerometer, battery, light, touch, click and charging pads. The bezel is the antenna.	3–5 years of updates est	Battery replaced at the boutique; module exchanged for the next generation
Dock	Charging stand with spring-loaded contacts (pogo pins) and USB-C	Long	Works with every module generation if the pad layout is kept

Why the stone is the module

It keeps the look of the reference design: a slim cuff with one long stone, no box on top.
The cuff can be finished and sold as jewellery, independent of the electronics.
No wires or batteries bend when the cuff opens, so flex fatigue disappears.
The antenna (the titanium bezel) sits above the titanium, not inside it, and is tuned once for all sizes.
A small sealed capsule is easier to make waterproof than a whole cuff.

What it costs us

Battery: the capsule only holds a ≈ 25–30 mAh cell, about 3 days of typical use est. Option B (longer hidden body) doubles that.
The cuff must thicken to 5.0 mm around the cup, so it is heavier at the top (≈ 19–20 g) est.
The latch must be excellent: secure, invisible and never released by accident.
A small, valuable part that comes out of the cuff can be lost; the app and the exchange programme must cover that.

Business model in short

One price for the set. Extra cuffs are inexpensive, so owners can have several and move the stone between them.
The Maison exchange: every 3–4 years the owner returns the module and gets the new one at a reduced price. Returned modules are refurbished or recycled.
Owners can buy more cuffs (another size or finish) and move one module between them.
Rules to freeze in v1 so every future module fits every cuff ever sold: the oval cup dimensions, the hook undercut and latch notch positions, the release-pin hole, the steel insert positions and the pad layout on the capsule underside.

02Specification

Key point

One recommended configuration. Every part has a named second source, and every number that is not from a datasheet is marked.

Cuff	Open rigid cuff in solid titanium Grade 23 (Ti-6Al-4V ELI, implant grade) V, 5-axis CNC from bar. 4 sizes S–XL, opening 35 / 37–38 / 39–40 / 41 mm. Band 10 mm wide and 2.4 mm thick in the arms, widening to 15 mm and thickening to 5.0 mm at the top est.
Cup	Oval cup ≈ 35.2 × 11.2 × 4.0 mm in the top of the cuff, 1.0 mm titanium floor, the same on every size: hook undercut at one end, latch notch at the other, a Ø1 mm release-pin hole through the floor, two ferritic steel inserts for the magnets est.
Stone module	Titanium bezel with gold-tone PVD ≈ 36 × 12 mm holding a smoked black sapphire cabochon ≈ 34 × 10 mm with a ≈ 1.5 mm dome. Hidden capsule ≈ 35 × 11 × 4.0 mm in titanium (zirconia as an option), 4 gold-plated charging pads underneath, IP68 est.
Height on the wrist	≈ 6.5 mm from skin to the top of the stone: 1.0 mm floor + 4.0 mm capsule + 1.5 mm stone est.
Weight	Stone module ≈ 4.3 g, cuff ≈ 19–20 g, total ≈ 23–25 g for size M est.
Chip and radio	Nordic nRF54L15, 2.45 × 2.25 mm, Bluetooth Low Energy V.
Microphones	2 × TDK T5838, 3.5 × 2.65 × 0.98 mm, wake-on-sound at 20 µA V; pinholes in the two bezel ends, ≈ 34 mm apart.
Memory	GigaDevice GD25LE128E, 128 Mbit: ≈ 2 h of offline audio plus an update slot.
Electronics	Rigid-flex: a main island ≈ 11 × 7 mm (chip, power chip, memory, crystals) and a light and sensor island under the stone, joined by flex; tall parts (microphones, accelerometer) at the capsule ends est.
Input	Touch on the stone (Azoteq IQS7222A), press on the stone (Qorvo FT-7600), taps (ST LIS2DUX12).
Feedback	Tiny LEDs under the stone; the stone clicks with a thin piezo bender (≈ 0.35 mm, custom, TDK PiezoHapt construction) driven by a Boréas BOS1901CW TC. No screen, no speaker.
Battery	One thin custom pill-shaped cell ≈ 29 × 7.6 × 2.0 mm, ≈ 25–30 mAh est. Prototypes: stock Grepow GRP1707026, 18.5 mAh, 25.8 × 6.5 × 1.7 mm V.
Battery life	Stone-only: ≈ 3 days typical when new, ≈ 2.5 days at end of life; ≈ 6 days in light use. Option B: ≈ 6 days typical est.
Charging	Stone out of the cuff, onto a dock with magnetic pogo pins (Mill-Max Maxnetic); full in ≈ 30–45 min est.
Audio to the wearer	Module → Bluetooth → phone app → assistant → the wearer's headphones, or the phone speaker.
Price	Set (cuff + stone module + dock) CHF 349, range CHF 299–399; module upgrade with trade-in CHF 129–149 est.

Decisions where the options disagreed

Topic	Decision	Why
Architecture	Permanent cuff + replaceable stone module. Rejected: electronics inside the crown; a cartridge inside the crown; a 34 × 15 × 7.4 mm block on top (looked like a gadget).	Keeps the reference look (one long stone flush in the band); separates jewellery life from electronics life.
Attachment	Magnets to seat, hook and hidden spring latch to lock, release pin from the skin side.	Nothing visible when worn; the release cannot be pressed while the cuff is on the wrist. Comparison in section 05.
Battery	One thin pill-shaped cell in the capsule (stock Grepow cells for prototypes, custom cell for production). Option B with a longer body as the fallback.	Only shape that fits a 35 × 11 × 4 mm oval; battery life is the main trade-off of the stone module.
Charging	Module on a dock with pogo pins. NFC wireless charging dropped.	Simplest and most efficient; no charger parts in the cuff; one less radio to certify.
Antenna	The titanium bezel, isolated on a zirconia ring; chip antenna under a ceramic capsule end as fallback.	The bezel sits above the titanium and is identical on every cuff, so it is tuned once. Simulate early.
Display	LED light glyph under the stone, not a screen.	Brightest through smoked sapphire, lowest power and cost.
Haptics	Thin piezo bender click (≈ 0.35 mm); no vibration motor.	The only actuator thin enough for a 4 mm capsule, and it makes the stone itself click. Needs a custom part.
Speaker	None in v1.	Space, battery and privacy. See section 09.
Capture	Gesture-first; always-listening is opt-in.	Battery, false triggers and recording law.

03System architecture

Key point

The module captures speech and sends it to the phone. The phone and the cloud do the heavy work. Replies play in the wearer's headphones; the module answers with light and a click.

Swipe the drawing sideways →

Figure 1. Block diagram. Gold dashed lines are wireless links. Headphone audio never leaves the phone; the module only sends compressed speech and receives control, light and click commands.

04How everything fits

Key point

Everything sits in a 35 × 11 × 4.0 mm capsule under the stone. The height adds up with no margin, and the cell is half of it, so battery capacity is the price of the slim look.

4.0 General arrangement, to scale (size M)

All three views share one scale. The gold part is the removable stone module; the rest is the permanent cuff. Use the 10 mm scale bar to measure.

Swipe the drawing sideways →

Stone module: cabochon 34 × 10 mm in a 36 × 12 mm titanium bezel, hidden capsule ≈ 35 × 11 × 4 mm in a cup in the cuff top. Band 10 mm × 2.4 mm at the ends, 15 mm × 5.0 mm at the top. Inner oval 58 × 46 mm, opening 37.5 mm, ≈ 6.5 mm from skin to the top of the stone (estimates).

4.1 Exploded view: stone module and cup

Swipe the drawing sideways →

Figure 2. The stone module lifted out of the oval cup. Band shown straightened; to scale at 12 px per mm est.

1Smoked black sapphire cabochon, 34 × 10 mm, 1.5 mm dome
2Titanium bezel 36 × 12 mm (gold-tone PVD), isolated: the antenna; microphone pinholes in both ends
3Capsule, 35 × 11 × 4.0 mm, titanium, sealed IP68
4Pill-shaped cell under the board islands
5Hook tab that goes in first
6Spring latch tongue
7Four flush gold-plated pads for the dock
8Two magnets in the capsule base
9Solid titanium cuff: 5.0 mm at the cup, 2.4 mm in the arms
10Oval cup, 4.0 mm deep, 1.0 mm floor, ferritic steel inserts under the magnets
11Release-pin hole through the floor, on the skin side

4.2 Stone module seen from above

Swipe the drawing sideways →

Figure 3. Top view, 20 px per mm. Dashed outlines are parts inside the capsule, under the stone.

1Cell, pill-shaped ≈ 29 × 7.6 mm, the largest shape that fits the oval
2Main island ≈ 11 × 7 mm: chip, power chip, memory, crystals
3Light and sensor island ≈ 10 × 6 mm: LEDs, touch, press, piezo driver
4Microphone A under the left pinhole
5Microphone B and accelerometer at the right end
6Two magnets in the base

4.3 Cross-section

Swipe the drawing sideways →

Figure 4. Section across the stone. Thicknesses to scale (50 px per mm); widths are schematic. Parts up to 0.6 mm sit on the top of the board; the taller microphones (0.98 mm) and accelerometer (0.74 mm) sit at the capsule ends, where there is no light layer est.

Layer, from the skin	mm
Cuff floor (titanium)	1.0
Capsule base with magnets and pads	0.4
Cell	2.0
Swell gap + foam/shield	0.25
Board islands, 6-layer HDI	0.35
Top-side parts and thin piezo	0.6
Light and touch flex + air gap	0.4
Capsule (base to stone seat)	4.0
Stone above the band surface	1.5
Skin to top of the stone	≈ 6.5 est

The 4.0 mm stack has no spare height. If a part comes out thicker (a 2.2 mm cell, 0.8 mm inductors), the capsule goes to 4.3 mm and the cuff top to 5.3 mm; the look survives it.

4.4 On the wrist

Swipe the drawing sideways →

Figure 5. Size M cuff seen along the forearm, 7 px per mm. The stone module sits flush in the band; the dotted box is the earlier block module for comparison est.

4.5 Option B: more battery under the band

Option B keeps the same stone and bezel, but the hidden body runs on under the band surface to ≈ 48 mm, so a longer curved cell fits.

	A · Stone only (design intent)	B · Extended body
Hidden body	35 × 11 × 4.0 mm, oval	≈ 48 × 12 × 4.0 mm, curved along the band
Cell	≈ 29 × 7.6 × 2.0 mm pill, ≈ 25–30 mAh est	≈ 40 × 10 × 2.0 mm curved, ≈ 50–60 mAh est
Typical battery life	≈ 3 days (≈ 2.5 at end of life) est	≈ 6 days (≈ 5 at end of life) est
Looks	Only the stone shows; the cup is hidden by the bezel	A fine seam line runs ≈ 6 mm past each end of the bezel
Cuff	5.0 mm thick over ≈ 40 mm	5.0 mm thick over ≈ 52 mm; ≈ +2 g
Module mass	≈ 4.3 g	≈ 6 g

Recommendation: build both in P1 (printed cuffs, real boards, stock Grepow cells) and decide after the one-week wear test. Stone-only is the design intent; Option B is the fallback if clients will not charge every two to three days.

4.6 Volume budget of the capsule

Inside the capsule: ≈ 34.2 × 10.2 mm oval × 3.2 mm ≈ 880 mm³ est.

Part	Envelope (mm)	mm³
Cell, pill-shaped	29 × 7.6 × 2.0	≈ 415
Cell swell allowance	29 × 7.6 × 0.15	≈ 30
Board islands	(11 × 7 + 10 × 6) × 0.35	≈ 50
Top-side parts zone	(11 × 7 + 10 × 6) × 0.6	≈ 80
Microphones and accelerometer at the ends	2 × 3.5 × 2.65 × 0.98 + 2 × 2 × 0.74	≈ 25
Light and touch flex	≈ 20 × 6 × 0.3	≈ 35
Thin piezo bender	≈ 20 × 6 × 0.35	≈ 40
Foam / shield	≈ 220 mm² × 0.1	≈ 20
Magnets, latch spring, hook	2 × Ø3 × 1 + latch	≈ 35
Pads and wiring	4 × Ø1.5	≈ 10
Adhesive, vents, gaskets	—	≈ 40
Total		≈ 780 (≈ 90 % of the volume) est

Very tight: the oval ends and the curve make the last 10 % hard to use. Height, not volume, is the binding limit.

4.7 Weight budget, size M

Item	Mass (g)
Stone module
Titanium capsule, 0.4 mm walls	≈ 1.2
Titanium bezel, gold-tone PVD	≈ 0.4
Sapphire cabochon 34 × 10 mm	≈ 1.1
Cell	≈ 0.7
Boards, parts, light, piezo	≈ 0.55
Magnets, latch, pads, adhesives	≈ 0.35
Module subtotal	≈ 4.3
Cuff
Top zone around the cup, 40 mm, 15 × 5.0 mm, minus the cup	≈ 7.9
Transitions, 2 × 15 mm	≈ 5.6
Arms, 60 mm, 10 × 2.4 mm	≈ 6.4
Cuff subtotal (≈ 19 g with 2.2 mm arms)	≈ 19–20
Total, size M	≈ 23–25 est

Within the 22–26 g target. Most of the cuff weight is the thick zone around the cup; a shorter transition or a lighter top zone with internal pockets saves 1–2 g.

4.8 Strength of the cuff

No flex fatigue: no wires, flex circuits or cells run through the band, so nothing electronic bends when the cuff opens.
Opening the cuff loads the titanium arms. For 2.4 mm arms (E = 114 GPa, R = 26 mm), stress is ≈ 345 MPa at an 8 mm opening and ≈ 430 MPa at 10 mm, close to the ≈ 470–500 MPa fatigue limit of Grade 23 est. Limit the service opening to 8 mm, or thin the arms to 2.2 mm. FEA and a 10,000-cycle coupon test remain mandatory.
The cup zone is 5.0 mm thick and does not bend, so the latch and the stone never see the opening load.

05Attachment

Key point

Recommended: magnets seat the stone, a hook and a hidden spring latch lock it, and a pin pressed through a hole on the skin side releases it. Nothing shows when worn, and it cannot be released while the cuff is on the wrist.

Option	How it works	Security	Feel and looks	Verdict
Magnets + hook + spring latch, skin-side release	Hook end in first, then the stone drops in; magnets pull it home and the latch clicks. To remove: take the cuff off, press the pin through the hole on the inner face, lift the stone.	High: the release hole is against the skin when worn	A soft magnetic pull and a click; nothing visible	Recommended
Magnets only	Strong magnets hold the stone in the cup.	Medium: can be knocked out	Very easy; risky for a precious part	Rejected
Bayonet quarter-turn	Turn the stone into lugs, like a watch caseback.	High	An oval stone cannot turn inside an oval cup	Rejected
Screw-down	Two screws from the skin side.	Very high	Needs a tool every time the owner charges	Rejected (boutique-locked option only)

Design rules

One standard oval cup on every cuff size and finish; checked with a master gauge stone at the end of the line.
Magnets (NdFeB, coated) sit sealed inside the capsule base; the cuff has small ferritic stainless steel inserts in the cup floor (no nickel against the skin).
Latch spring and tongue sit in a blind pocket outside the sealed electronics volume. Release pin travel ≥ 0.6 mm; the dock carries a small tool for owners with short nails.
Materials: titanium or 316L latch parts, hardened faces, no plating that can flake TC.

Test requirements

Test	Requirement
Pull-off, straight up, latch engaged	≥ 80 N without release est
Side push on the stone	≥ 50 N without release or movement est
Release pin	4–8 N, ≥ 0.6 mm travel; the stone only lifts when the pin is pressed est
Magnet seating	Pulls the stone home from ≥ 1 mm; ≤ 2 N to lift once released est
Cycle life	5,000 remove and refit cycles (≈ 3 a day for 4 years), retention still ≥ 80 % est
Drop	1.5 m onto hard floor, 26 drops in all orientations: the stone stays in and works est
Sweat and corrosion	7-day artificial sweat soak and 96 h neutral salt spray (ISO 9227) on latch, hook, inserts and pads: no corrosion, no sticking est
Rattle	Free play ≤ 0.05 mm; no audible rattle est

06Bill of materials

Key point

Module electronics cost ≈ $61 per unit at 1,000 and ≈ $33 at 10,000 est. Board making and assembly are the biggest lines, not the chips.

Group	@1k	@10k
Core silicon: chip, 2 microphones, memory, power chip, accelerometer, crystals	$11.43	$9.06
Stone interface: touch, press, piezo click, LEDs	$9.60	$4.40
Antenna, passives, protection	$0.95	$0.60
Power: cell, protection, pads	$6.80	$4.40
Mechanics in the module: latch, magnets, acoustic vents	$5.50	$3.00
Board and assembly	$27.00	$12.00
Module electronics	≈ $61	≈ $33

Full bill of materials 23 lines with part numbers and second sources

#	Part	Function	Size (mm)	Qty	Buy at	@1k	@10k	Second source
Core silicon
1	Nordic nRF54L15-CAAA-R7	Bluetooth chip, codec, crypto	2.45 × 2.25 × 0.42	1	DigiKey, Future, Farnell	2.90	2.00	nRF54LM20A; nRF5340
2	TDK MMICT5838-00-012	Microphone with wake-on-sound	3.5 × 2.65 × 0.98	2	Avnet, DigiKey, Farnell	2.50	2.22	Knowles SPH0641LU4H-1; Infineon IM69D128S
3	GigaDevice GD25LE128E	128 Mbit memory: audio + updates	3 × 3 × ≤ 0.6	1	LCSC, Braemac	1.75	1.30	Winbond W25N01GW
4	Nordic nPM1304-CAAA-R7	Power chip, charger, fuel gauge	3.1 × 2.4	1	DigiKey, Future	1.56	1.38	nPM1300; TI BQ25120A TC
5	ST LIS2DUX12TR	Accelerometer with tap detection	2.0 × 2.0 × 0.74	1	ST, RS	1.50	1.20 est	Bosch BMA530 / BMA580
6	ECS-320-CDX-2374	32 MHz crystal	1.2 × 1.0	1	DigiKey	0.72	0.61	Murata / TXC / Epson TC
7	Epson FC-12M	32.768 kHz crystal	2.05 × 1.2	1	RS	0.50	0.35	Epson FC-12D
Stone interface
8	Azoteq IQS7222A	Touch through the stone	1.62 × 1.62	1	DigiKey, Mouser	0.60 est	0.40	Infineon PSOC 4000T; Microchip CAP1203
9	Qorvo FT-7600	Press on the stone	0.8 × 1.2 × 0.22	1	Qorvo (quote)	1.00 est	0.50 est	Qorvo FT-4100; TI LDC2114
10	Thin piezo bender, custom (TDK PiezoHapt construction)	Piezo: the stone clicks	≈ 20 × 6 × 0.35	1	TDK (custom quote) TC	3.00 est	1.50 est	PI Ceramic custom bender
11	Boréas BOS1901CW	Piezo driver	2.1 × 2.2	1	Mouser	2.00 est	1.00 est	Boréas BOS1931
12	ROHM SML-P12 / LITEON LTW-FC03DCD5 + driver	LED glyph (10–30 LEDs)	1.0 × 0.6 × 0.2	set	DigiKey, Mouser	3.00 est	1.00 est	Vishay 0201 LEDs
Antenna, passives, protection
13	Bezel feed + matching, or Antenova Weii SRCW004	Antenna	0201 / 1.0 × 0.5	1	Murata, Johanson, Antenova	0.40 est	0.25 est	Johanson 2450AT18A100
14	Passives, ≈ 40	Decoupling, inductors	01005 / 0201	set	LCSC, DigiKey	0.40 est	0.25 est	—
15	TVS diodes	ESD on pads and ports	0201	4	Nexperia, TI	0.15 est	0.10 est	—
Power
16	Custom pill-shaped LiPo cell (prototypes: Grepow GRP1707026, 18.5 mAh V)	LiPo cell, ≈ 25–30 mAh est	≈ 29 × 7.6 × 2.0	1	Grepow	2.50 est	1.60 est	EEMB or Jauch custom
17	Protection IC (TI BQ2970 / ABLIC S-82) + NTC + cell flex	Cell protection, service connector	on cell	1	Cell maker	2.50 est	1.80 est	Jauch
18	Bulk capacitors	Peak buffer	low profile	set	Murata, TDK	0.30 est	0.20 est	—
19	4 gold-plated charging pads in ceramic inserts	Dock contacts	Ø1.5	4	Case maker TC	1.50 est	0.80 est	—
Mechanics in the module
20	Latch tongue and spring, hook, 2 NdFeB magnets	Attachment	magnets Ø3 × 1	set	Case maker TC	4.50 est	2.30 est	—
21	W. L. Gore GAW337 / GAW338	Waterproof acoustic vents	Ø ≈ 2–3	2	Gore	1.00 est	0.70 est	Nitto Denko TC
Board and assembly
22	Rigid-flex: two 6-layer HDI islands joined by flex	Boards	11 × 7 and 10 × 6	1	Dyconex (CH)	12.00 est	6.00 est	Cicor; Würth; AT&S
23	Assembly, underfill, test	PCBA	—	1	Cicor, Boudry (CH)	15.00 est	6.00 est	Shenzhen EMS
Total module electronics						≈ $61.28	≈ $33.46	est

Changed against the block module: a smaller pill-shaped cell, a custom thin piezo instead of the 1.4 mm PowerHap, two board islands on rigid-flex, magnets added, the dovetail rail removed. The dock is costed separately in section 12.

Enclosure parts per unit

Line	@1,000	@5,000	@20,000
Cuff
Solid titanium cuff, CNC, brushed and bead-blasted	$25–45	$14–26	$10–18
Oval cup, hook undercut, latch notch, release hole, steel inserts	$6–12	$3–6	$2–4
Module housing
Titanium capsule and base, CNC	$10–18	$6–12	$4–8
Sapphire cabochon 34 × 10 mm, smoked coating	$10–20	$6–12	$4–8
Titanium bezel, gold-tone PVD, zirconia insulator	$5–10	$3–6	$2–4
Sealing (bonding, base O-ring), leak test	$3–6	$2–4	$1.5–3
Tooling and fixtures (4 cuff sizes, 1 module, stone, coating, 2 RF loops)	$40–90k once

Titanium only, no precious metals. Prototypes are machined in Switzerland; production parts come from an Asian titanium case maker that already makes watch cases (for example Boze Titanium, section 11). All figures are estimates until we have three quotes TC.

07Cuff, module housing and stone

Key point

The cuff and the module housing are machined titanium, made the same way as a watch case. Prototypes in Switzerland, production with an Asian titanium case maker.

Materials and finishes

Element	Specification	Suppliers
Cuff	Ti-6Al-4V ELI Grade 23 bar with EN 10204 3.1 certificates; no nickel. 5-axis CNC from bar, hand polish or satin brush, bevelled edges. Forged blanks above 5k units.	Bar: Harald Pihl (SE), Bibus Metals (CZ/CH). CNC: MRP SA (Alle), Queloz SA (Saignelégier), Simon Et Membrez (Delémont); Boze (CN)
Outer finish	Brushed and bead-blasted natural titanium, with no coating to wear off. Black DLC as a second finish later.	Case maker; DLC by the case maker or Oerlikon Balzers (LI) TC
Inner face	Raw polished Grade 23 against the skin. No liners.	—
Module capsule	Grade 23 titanium (zirconia ceramic as an option), 0.4 mm walls, hidden in the cup; base held by two M1.0 screws and an O-ring so the battery can be serviced.	Same case makers TC
Bezel	Thin oval bezel 36 × 12 mm in titanium with gold-tone PVD. Isolated from the capsule on a zirconia ring because it is the antenna.	Case maker; PVD by the coater TC

The stone

Synthetic sapphire cabochon ≈ 34 × 10 mm with a ≈ 1.5 mm dome and a flat polished back.
Smoked black look: clear sapphire with a dark coating on the back (10–30 % light through a small window for the LEDs, ≤ 5 % elsewhere). Opaque black sapphire cannot pass light and is only for a no-light edition.
The dome bends the light, so the LED window is tested on real cabochons, not flat samples TC.
Anti-reflection coating on the inner face only, because an outer coat scratches.
Suppliers: Stettler Sapphire (Lyss) first, Saphirwerk (Brügg) second, Sun Yin Crystal (Hong Kong) for the China route.

Antenna

Titanium blocks radio, so a metal part has to become the antenna. Primary: the titanium bezel around the stone, isolated on a thin zirconia ring and fed through a spring contact inside the capsule.
The bezel stands above the titanium band and is identical on every cuff, so it is tuned once on a master cuff instead of once per size.
It sits only ≈ 1 mm above the titanium surface, which still detunes it; simulate (CST or HFSS) with a wrist model before cutting metal and budget two tuning loops.
Fallback: a chip antenna (Antenova Weii) under a zirconia end of the capsule. Partners: Ignion, Taoglas, Antenova, CSEM.

Sealing (module only)

Joint	Method
Stone to bezel, bezel to shell	Light-curing sealing adhesive (DELO PHOTOBOND class) plus a structural fillet
Base to capsule	2 M1.0 screws and an FKM O-ring, like a small watch caseback; opened only at the Maison
Microphone ports	Pinholes in the two bezel ends → channel into the capsule → Gore GAW337/338 membrane (IP68) → gasket → microphone; 1–3 dB loss expected est
Charging pads	Gold-plated pads bonded in ceramic inserts, flush with the base
Latch and magnets	Latch outside the sealed volume in a blind pocket; magnets sealed inside the base

Tests: IP68 at 1.5 m for 30 min (IEC 60529) and 3 ATM (ISO 22810). Skin contact: EN 12472 wear then EN 1811 nickel release on the cuff and the module base; ISO 10993-5/-10 on finished coated parts.

08Battery and charging

Key point

The stone-only capsule fits a ≈ 25–30 mAh cell: about 3 days of typical use, 6 days of light use. Option B doubles it. The stone charges on a dock in 30–45 minutes while the cuff stays on the wrist as jewellery.

Cell candidates

Cell	Size (mm)	Capacity	Fit
Custom pill-shaped cell (Grepow)	≈ 29 × 7.6 × 2.0	≈ 25–30 mAh est	Production cell for the stone-only module
Grepow GRP1707026 V	1.7 × 6.5 × 25.8	18.5 mAh	Stock prototype cell for option A (≈ 2 days typical)
Grepow GRP1607027 V	1.6 × 6.5 × 26.5	17 mAh	Second stock prototype cell
Custom curved cell, Option B (Grepow)	≈ 40 × 10 × 2.0, bend radius ≈ 30	≈ 50–60 mAh est	Production cell for Option B (Grepow lists a 28.5 mm minimum bend radius TC)
Grepow GRP2508030 V	2.55 × 8.1 × 29.2, curved	40 mAh	Stock prototype cell for Option B in a 4.6 mm body
EEMB LP301230 V	3.5 × 12.5 × 31	70 mAh	Too thick for the stone module (was the block-module cell)

Grepow figures from the Grepow curved-battery catalogue. Custom capacities scaled from those cells at ≈ 0.065–0.075 mAh per mm³ est; confirm with Grepow, with UN38.3 reports, discharge rate and minimum order TC.

Power draw (from the earlier power study, unchanged electronics)

Mode	Average current	Charge
Idle: tap wake armed, Bluetooth kept alive	≈ 40–55 µA	≈ 1.2 mAh/day
Listening-mode standby (one microphone on wake-on-sound)	≈ 45–55 µA	≈ 1.3 mAh/day
Recording to memory	≈ 2.5–3.5 mA	≈ 3 mAh/h
Live streaming to the phone	≈ 3.5–5 mA	≈ 4.5 mAh/h
Light glance (5 s)	≈ 4–5 mA	≈ 6 µAh

Battery life

Use	mAh/day	A · stone only, new / end of life	B · extended, new / end of life
Light: 20 min capture, 40 glances	≈ 3.8	≈ 6.3 / 5 d	≈ 13 / 10.5 d
Typical: 1 h capture, 100 glances	≈ 8	≈ 3 / 2.4 d	≈ 6.2 / 5 d
Listening mode, light (2 h speech)	≈ 6.7	≈ 3.6 / 2.8 d	≈ 7.5 / 6 d
Listening mode, typical (4 h speech)	≈ 11.7	≈ 2 / 1.6 d	≈ 4.3 / 3.4 d
Heavy (noisy office, TV)	≈ 19–22	≈ 1 d	≈ 2.5 d

Usable ≈ 24 mAh new and ≈ 19 mAh at end of life for A; ≈ 50 and ≈ 40 mAh for B est. Honest customer claim for A: “two to three days; about a week in light use”. Ways to stretch it: gesture-first capture, a longer idle Bluetooth interval, and a travel écrin that tops the stone up. Confirm with a power profiler on the development kit.

Dock

Desk stand and travel écrin with magnetic pogo pins (Mill-Max Maxnetic) and USB-C. The stone drops onto it; magnets align it. The écrin can carry its own cell to top the stone up on the move.
Pads are live only on the dock, with reverse and ESD protection; charge at 0–45 °C; full in ≈ 30–45 min est.
Optional: a second module so the owner never waits; or wear the cuff alone while charging.

EU Battery Regulation

Article 11 applies from 18 February 2027; a delegated act adopted on 14 July 2026 lets wearables keep a battery that only an independent professional replaces V. Our answer: a screwed module base, a connectorised cell, published instructions, spare cells for ≥ 5 years and a boutique battery service. Cells need UN38.3 and IEC 62133-2.

09Stone interface, firmware, app and audio

Key point

The stone is the whole interface: it lights, senses touch and press, and clicks. Spoken replies come through the phone, not from the module.

The stone

Light: a line, a pulse, three to five icons and a recording dot, made of tiny LEDs behind the dark coating.
Touch: a transparent electrode on the back of the stone; two electrodes allow a swipe.
Press: a force sensor under the stone seat.
Click: the piezo moves the stone ≈ 15 µm in under 1 ms, like a laptop trackpad.

Gesture	Action
Press and hold the stone	Talk to the assistant
Double tap on the cuff	Start or stop recording, confirmed by a click and a line of light
Triple tap	Privacy mute
Swipe across the stone	Optional

Firmware

Layer	Choice
RTOS / SDK	nRF Connect SDK 3.x (Zephyr)
Secure boot and updates	MCUboot with Ed25519 signatures, keys in the nRF54L KMU (provision on first flash); SMP over BLE; secondary slot on the external NOR (≈ 1.5 MB, rest for audio); anti-rollback; staged rollout 1 % → 10 % → 100 %
Audio front end	PDM at 16 kHz → high-pass → optional fixed delay-and-sum of two mics → AGC; 200–300 ms ring buffer to cover the 50–150 ms wake latency
Codec	Opus (CELT low complexity, ≈ 14–20 % CPU on M33 est) or LC3 via Google liblc3 (Apache-2.0); decided by benchmark
Transport	Custom GATT service (Omi-style): audio notify, codec ID, control point; sequence + timestamp header; 2M PHY, 2–3 frames per connection event. ≈ 1.3 Mbps measured on 2M PHY vs 16–32 kbps needed: radio-on time, not throughput, is the constraint.
Offline	Encrypted (AES-256-GCM, KMU key) store-and-forward on NOR, wiped after phone acknowledgement
Our own modules	Trigger manager, speech check, light and click grammar, factory test mode, crash dumps

Audio path to the headphones

The Bluetooth chip in the module cannot stream audio to AirPods, and iPhones do not support LE Audio. The path is therefore: module → Bluetooth → phone app → speech-to-text → assistant → speech synthesis → headphones. Because the microphone is in the module, the phone never opens its own microphone and the headphones keep full sound quality. Expected delay ≈ 0.8–1.4 s est. Without headphones: phone speaker, a notification, or a click and a line of light.

Built-in speaker: not in v1

Factor	Speaker in the module	Headphones or phone (v1)
Space	Needs its own air volume and an opening; the module is already ≈ 90 % full	No cost
Power	≈ 100–300 mW while playing est; battery would drop to a few days	Phone and headphones pay
Sound	Thin and quiet at wrist distance	Full quality
Privacy	Everyone nearby hears the reply	Private
Water and looks	Another hole and membrane; a visible grille	Only the microphone ports

Voice recorders and pendants (Plaud, Bee, Limitless) also have no speaker. Because the module is replaceable, a speaker can be added in a later module generation if users ask for it, with no change to the cuff.

Phone and cloud

iOS (top software risk): pair with AccessorySetupKit from day one; the “phone locked, music playing, press, hear the answer” test is a week-3 go/no-go.
Android: CompanionDeviceService, with a foreground service as fallback.
Apple MFi: not required for Bluetooth Low Energy accessories.

Line (per user per month)	Lean stack	Premium stack
Speech-to-text (120 min)	Soniox $0.24, or Apple on-device $0	Deepgram Nova-3 multilingual $0.70
Assistant (900 turns, ≈ 3K in / 300 out)	Claude Haiku 5.5 ≈ $0.41	Claude Sonnet 5.5 ≈ $8.10 (≈ $4 with caching)
Speech synthesis (900 replies)	Apple on-device $0, or Gemini Flash-Lite TTS ≈ $2.2	ElevenLabs Flash ≈ $7.20 (signature Maison voice)
Infrastructure	≈ $0.3–0.5	≈ $0.5–1
Total	≈ $1–3	≈ $12–17

Simple requests (timer, note, reminder) run on the phone; harder ones go to the cloud. Budget ≤ CHF 1 per user per month est; keep vendors swappable because model prices change.

Privacy and the law

Hidden jewellery and recording law pull in opposite directions. Swiss criminal code Art. 179ter forbids recording a private conversation without consent; Germany has §201 StGB; about a dozen US states require everyone's consent.

Default: the wearer starts every recording; no rolling buffer of other people's speech. Listening mode is opt-in, time-limited, and stops off the wrist.
Notice: during capture the stone shows a faint glow line and the wearer feels a click.
Security: encrypted Bluetooth pairing, encrypted audio frames and memory, TLS 1.3, audio deleted within 24 h by default (proposal).
Losing a module: data on it is encrypted and the app can block it; the owner's history lives in the account, so a replacement module restores it.
Compliance: GDPR impact assessment, Swiss nFADP, EU AI Act Art. 50 transparency, Cyber Resilience Act, RED EN 18031. Counsel sign-off before the design is frozen.

10Make, customise or buy

Key point

Buy the chips; have suppliers make our designs (cuff, module housing, stone, board, cell); do firmware, app, design, final assembly and quality in-house.

Buy catalogue part · Custom our design, made by a supplier · Make in-house

Subsystem	Decision	Who	Why
Chip, power chip, microphones, memory, sensors	Buy	Nordic, TDK, GigaDevice, ST	Standard parts; a ready radio module (Raytac AN54L) can be used in early prototypes
Touch, press, piezo, LEDs	Buy chips, Custom layout	Azoteq, Qorvo, TDK, Boréas, ROHM	The stone mechanics are our know-how
Cell	Buy now, Custom later	Grepow stock cells; Grepow custom pill and curved cells	Stock cells to start fast; custom cells to fill the oval capsule
Antenna	Custom	Bezel design with Ignion or Taoglas	Top radio risk
Board and assembly	Custom	Dyconex, Cicor (CH) or PCBWay/JLCPCB for prototypes; Asian EMS for production	Cost at volume
Cuff (all sizes)	Custom	Swiss CNC (MRP, Queloz) for prototypes; Asian titanium case maker for production	Our design, their machines
Capsule, bezel, latch and magnets	Custom	Same case makers TC	Watch-head-type part
Stone and smoked coating	Custom	Stettler Sapphire; Saphirwerk	Tint must be qualified
PVD finish	Custom	Positive Coating; Oerlikon Balzers	Specialist process
Dock and écrin	Custom	Mill-Max pogo pins; EMS for the board	A branded daily ritual
Firmware, app, cloud	Make	In-house; Nordic partners (GoodByte, Elimo, Zühlke) for support	Core know-how
Jewellery design	Make	In-house designer + Creaholic or Helbling for manufacturability	The Maison owns the look
Final assembly, sealing, test	Buy	EMS in Asia; quality sign-off in Geneva	Keeps the price at CHF 349
Certification	Buy service	Montena, TÜV SÜD, Eurofins, SGS TC	Mandatory third-party testing

11Suppliers directory

Key point

About 50 suppliers, mostly in Switzerland and Europe for the jewellery parts and assembly, with named Asian second sources for volume.

Show all suppliers name, location, role, link

Scroll the table sideways →

Supplier	Location	What for Le Pinson	Link
Nordic Semiconductor	Trondheim, NO	nRF54L15 SoC, nPM1304 PMIC, dev kits, PPK2	nordicsemi.com
TDK InvenSense	San Jose, US	T5838 PDM microphones, EV_T5838-FX2	invensense.tdk.com
GigaDevice	Beijing, CN	GD25LE128E 1.8 V NOR flash	gigadevice.com
STMicroelectronics	—	LIS2DUX12 accelerometer with tap engine	st.com
Bosch Sensortec	Reutlingen, DE	BMA530 / BMA580 accelerometer (second source)	bosch-sensortec.com
ECS Inc.	Olathe, US	32 MHz crystal	digikey.com
Azoteq	Paarl, ZA	IQS7222A touch / inductive sensing	azoteq.com
Qorvo	—	FT-7600 MEMS force sensor	qorvo.com
TDK Electronics	—	PiezoHapt thin piezo actuators (custom bender quote)	tdk-electronics.tdk.com
Boréas Technologies	—	BOS1901CW / BOS1931 piezo drivers	boreas.ca
ROHM / LITEON / Vishay	—	Micro-LEDs for the light glyph	digikey.it
Texas Instruments	—	DRV2605L LRA driver (fallback), LDC2114	ti.com
Precision Microdrives	—	C08-00A Ø8 × 2.6 mm LRA (fallback)	precisionmicrodrives.com
DisplayModule	—	DM-OLED042 0.42" PMOLED for EVT; custom PMOLED quotes	displaymodule.com
Grepow	Shenzhen, CN	Curved LiPo cells and pack assembly	grepow.com
Jauch	DE	Custom pack integration, cell second source	TC quote needed
LiBEST	Daejeon, KR	Flexible Li-ion second source	startup-seeker.com
VARTA Microbattery	Ellwangen, DE	CoinPower crown-only fallback	texim-europe.com
Renesas (Panthronics)	—	PTX30W / PTX130W NFC wireless charging	renesas.com
Mill-Max	US	Maxnetic magnetic pogo connectors for the stand	mouser.in
W. L. Gore & Associates	Newark, US · Putzbrunn, DE	GAW337/338 acoustic vents	gore.com
Ignion	Barcelona, ES	Antenna design service, Fast Track matching	st.com
Taoglas	Enniscorthy, IE	Antenna design, LDS	taoglas.com
Antenova	—	Weii SRCW004 chip antenna (EVT fallback)	mouser.com
Dyconex (Somacis)	Bassersdorf, CH	Ultra-thin any-layer HDI rigid-flex, LCP	medicaldevice-network.com
Cicor Group	Boudry, CH	PCBA down to 01005, rigid-flex, ISO 13485	cicor.com
Würth Elektronik	DE	Rigid-flex, EVT partner	we-online.com
Valtronic	Les Charbonnières, CH	Medical micro-assembly (to confirm consumer appetite)	pitchbook.com
SVtronics	Plano, US	Ring-scale wearable EMS (US option)	digikey.co.uk
MRP SA	Alle, JU, CH	Primary Swiss titanium cuff maker candidate	provenexpert.com
Queloz SA (CMSA group)	Saignelégier, JU, CH	High-end titanium cases, small series	cmsa.ch
Simon Et Membrez (Swatch Group)	Delémont, JU, CH	Second Swiss case source	swatchgroup.com
Boze Metal / Boze Titanium	Baoji / Shenzhen, CN	Gr23 stock and Ti CNC, China route	cnc.bozemetal.com
Harald Pihl	SE	Grade 23 bar with 3.1 certificates	haraldpihl.com
Bibus Metals	CZ / CH	Grade 23 bar	bibusmetals.cz
Stettler Sapphire (IMI)	Lyss, BE, CH	Crown stone, dead-front coating, metallisation	europastar.com
Saphirwerk	Brügg, BE, CH	Stone second source, ceramics	bioalps.org
Sun Yin Crystal	Hong Kong	Coloured / coated sapphire, MOQ 100	hktdc.com
Metoxit AG	Thayngen, SH, CH	Y-TZP zirconia inner plate	zwp-online.info
Positive Coating SA	La Chaux-de-Fonds, NE, CH	PVD / ALD champagne and gold, DLC	positivecoating.ch
Oerlikon Balzers	Balzers, LI	BALINIT gold 1N14 / 2N18, DLC	oerlikon.com
Blösch AG	Grenchen, CH	PVD and galvanics for exterior watch parts	bloesch.ch
DELO	Windach, DE	Seal-bonding adhesives	delo-adhesives.com
Costanzo & Rizzetto	Valenza, IT	Stone setting, high-jewellery finishing	cbinsights.com
Swiss m4m Center	Bettlach, CH	SLM titanium prototypes (ISO 13485)	empa.ch
Creaholic	Biel, CH	Engineering design house, DFM	en.wikipedia.org
Helbling Technik	Zurich, CH	Engineering design house	s-ge.com
GoodByte · Elimo · EUB · Zühlke	Wrocław · — · Mölndal · Zurich	Nordic design partners for firmware	response.nordicsemi.com
HEAD – Genève	Geneva, CH	Jewellery and accessory design talent	hesge.ch
Kiwa · TÜV SÜD	DE · —	Battery testing (UN38.3, IEC 62133)	kiwa.com
EEMB	CN	Stock and custom LiPo cells; second source for the custom cells	EEMB overview (SOS Electronic)

12Manufacturing, cost, pricing and timeline

Key point

A set costs ≈ $100–160 to make at 5,000 units and ≈ $75–120 at 20,000 est. A retail price of CHF 349 works from about 10,000 sets a year; the first batch has a thin margin.

Supply chain

Prototypes and the pilot run in Switzerland, close to the team, for fast changes.
Production: cuff and capsule from an Asian titanium case maker; electronics, final assembly and test at an Asian EMS.
Design, firmware, app and quality control stay in Geneva, with sample checks on every batch.
Label: “Designed in Geneva”. “Swiss made” needs ≥ 60 % of the manufacturing cost in Switzerland, which does not fit a CHF 349 price.

Certification

Only the module is a radio product. The cuff is jewellery: it needs nickel-release testing (EN 1811) but no radio, EMC or WEEE certificates, so new cuff finishes do not need re-certification (only an antenna check on new metals).

Certification table schemes, cost, duration; total $110–220k

Scheme	What applies	Cost	Duration
EU RED 3.2 radio	EN 300 328 (BLE), module only	€4–8k	3–5 wk
EU RED 3.1(b) EMC	EN 301 489-1/-17	€3–6k	same window
EU RED 3.1(a) safety, RF exposure	EN 62368-1; EN 62479 / EN 50663	€2–4k	2–3 wk
EU RED 3.3 cybersecurity	EN 18031-1/-2 (voice is personal data); Notified Body if a restriction is triggered	€8–25k (+€10–30k NB) est	4–10 wk
RoHS, REACH, nickel	XRF/ICP; EN 12472 then EN 1811 per finish	€1–3k + €300–1,000/sample	2–3 wk
IP rating	IEC 60529 IP68; ISO 22810 if called water-resistant	$550 – €5k	1–2 wk
Battery	UN38.3 per cell model; IEC 62133-2 cell + pack CB	≈ $1.5–5k + ≈ $6,350	6–8 wk + 6–10 wk
EU Battery Regulation	Art. 11 derogation file, labelling, QR from 18 Feb 2027, EPR per country	€3–8k est	—
GPSR, WEEE	EU responsible person (Van Roye is non-EU); WEEE registration per country	€1.5–5k/yr; €200–1,500/country/yr	—
USA FCC	Part 15.247, 15B, RF exposure, TCB grant	$9–20k (+$5–15k per retest)	3–6 months end to end
Canada ISED	RSS-247, RSS-Gen, RSS-102; Canadian representative	≈ $3k + CAD 1,200 fee	with FCC
Bluetooth SIG	Product qualification	$11,500 (Contributing Adopter, small) or $12,000	1–3 wk
Japan MIC	Radio Law certification	$5–12k est	4–8 wk
Switzerland, UK	OFCOM accepts CE radio equipment; UK recognises CE indefinitely	≈ 0	—
Compliance allowance, one retest round included		$110–220k est	4–6 months, overlapping DVT/PVT

Cost per set

Scroll the table sideways →

Line	1,000	5,000	20,000
Cuff: machining, finish, oval cup	$31–57	$17–32	$12–22
Module
Electronics	$61–70	$40–50	$33–40
Housing, stone, bezel, sealing	$28–54	$17–34	$12–23
Assembly and test (EMS)	$8–14	$5–9	$4–7
Module subtotal	$97–138	$62–93	$49–70
Dock	$10–16	$7–12	$5–9
Packaging and sizing kit	$8–14	$5–9	$4–7
Yield, freight, duties	$15–25	$8–15	$6–11
Cost per set (landed)	≈ $160–250	≈ $100–160	≈ $75–120
+ certification spread over the units	+$110–220	+$22–44	+$6–11
+ tooling and fixtures	+$40–90	+$8–18	+$2–5

All estimates. To sell at CHF 349 with a healthy margin, a set should cost under ≈ $110 (≈ CHF 90) to make, which needs ≈ 10,000–20,000 sets a year.

Pricing

Product	Suggested retail
Set: titanium cuff + stone module + dock	CHF 349 (test CHF 299–399)
Extra titanium cuff (other size or finish)	CHF 89–119
Stone module alone	CHF 199
Module upgrade with trade-in	CHF 129–149
Battery service (module swap)	CHF 49

All prices are estimates for discussion and include VAT. Gross margin at 20,000 sets ≈ 65–75 % selling direct and ≈ 35–45 % through retailers, who take 30–40 % est. The cloud must stay at or below ≈ CHF 1 per user per month; there is no room for more at this price.

Timeline

Swipe the drawing sideways →

Figure 6. Programme timeline: 20–26 months to first customer. The budget is in section 13. Not yet re-planned for the module design, which takes the cuff off the electronics critical path and may save 1–2 months.

Phase	Duration	What is built	Exit criteria
Feasibility (P0–P2)	3–4 mo	Dev kits, printed cuffs and modules, 5–10 working prototypes	Audio end to end; battery projection for options A and B; latch mock-ups pass pull and cycle tests; Bluetooth range of the module on a metal cuff
EVT (2 rounds)	5–7 mo	20–30, then 40–60 units, machined titanium	Board frozen; antenna tuned; early radio and sweat tests; cell qualification started
DVT	4–6 mo	150–250 units on production processes	Formal CE, FCC, ISED, Bluetooth SIG; IP68; drop, sweat, latch life; 30–50 user beta
PVT	3–4 mo	1,000–2,000 first production sets	Yield ≥ 90 %; certificates granted; dock and packaging final
Production	from month 20–26	5,000 → 20,000+ per year	Returns < 2 %; second supplier qualified
In parallel: firmware, apps, cloud, privacy	whole programme	≈ 8.5 people	Software milestones M1–M5
To first customer	20–26 months		Budget: section 13

Long lead items: cell qualification then UN38.3 (6–8 weeks) and IEC 62133-2; titanium fixtures and finishing at the case maker (8–12 weeks each, est); nRF54L15 and nPM1304 at ≈ 20 weeks factory lead time; radio retests 4–8 weeks each; stone tint qualification.

13Funding: what we need to raise

Key point

About CHF 5–7.5M to reach the first customer and about CHF 12–18M in total, in three rounds, to reach break-even est. At CHF 349 the business lives on volume: break-even is ≈ 30,000–60,000 sets a year.

How accurate are these prices?

Electronics: good, within about 20 %. Distributor prices; the custom cell and thin piezo still need quotes.
Titanium parts: fair, within about 40 %. No quotes yet; get three from Asian case makers in the first 90 days.
Certification and cloud: good. Published fees and API prices.
Retail price CHF 349: our target, not yet tested with buyers.
The earlier luxury version (CHF 2,400 and up, gold editions, Swiss production) is dropped.

Budget to the first customer (months 0–24)

Scroll the table sideways →

Line	CHF est	Basis
Team: on average 8 people for 24 months (≈ 16 person-years)	2.2–3.0M	Swiss base pay for hardware and embedded engineers CHF 98–127k (Payscale 2026) V; ≈ CHF 140–190k per person with social charges
Outside engineering: antenna, acoustics, industrial design, factory set-up	0.3–0.6M	—
Prototype builds, EVT and DVT	0.3–0.6M	≈ 250–350 units
Tooling and fixtures	0.05–0.1M	Section 7
Certification, one retest round	0.1–0.2M	Section 12
First production stock: 2,000 sets	0.25–0.4M	≈ $160 per set
Legal and IP: company, trademarks, patents, recording-law opinion	0.1–0.2M	—
Brand and launch	0.3–0.6M	—
Geneva office and administration	0.2–0.4M	—
Software tools and cloud during development	0.05–0.1M	—
Subtotal	3.9–6.2M
Contingency 20 %	0.8–1.2M	Hardware programmes usually overrun
Total to first customer	≈ 5–7.5M

After launch, to break-even

Per set sold: ≈ CHF 120–160 left after VAT, making cost, payment fees, returns, warranty and three years of cloud est.
Costs per year: team of 15–20 CHF 2.5–3.5M; marketing CHF 2–4M; office and admin CHF 0.5M est.
Break-even: ≈ 30,000–60,000 sets a year est. Until then the business needs ≈ CHF 6–10M more, including stock.
An optional subscription for heavy users would lower the break-even point.

Three rounds

Scroll the table sideways →

Round	Amount est	Months	What it pays for	Proof needed for the next round
Pre-seed	CHF 0.8–1.2M	0–6	Founders and 3 hires; kit; prototypes; trademarks; three factory quotes	A working stone module on a cuff; wear test; battery life measured; a cost per set under ≈ $110 at volume confirmed by quotes
Seed	CHF 4–6M	6–24	EVT, DVT, PVT; certification; first 2,000 sets; launch	Certified product; pre-orders; daily-use and return data
Series A	CHF 7–11M	22–40	Stock, marketing, retail partners, module 2	Sales growing towards 30,000+ sets a year
Total	≈ CHF 12–18M

Other money besides equity

Pre-orders: 1,000–3,000 pre-orders with a CHF 50–100 deposit, or a crowdfunding launch, bring in cash and are the best proof of demand.
Swiss support: Innosuisse projects with a research partner such as CSEM or HES-SO; Venture Kick; Geneva's FIT foundation TC.
Strategic partner: a watch or electronics group could bring manufacturing and distribution, at the cost of control.

Comparable companies

Scroll the table sideways →

Company	Product	Price	Funding	Notes
Nirva	Pendant, also worn as a bracelet; ≈ 8 g; up to 3 days battery	$249	$33M: $8M earlier in 2026, $25M pre-Series A on 22 Oct 2026 (Lightspeed, South Park Commons)	Records only the wearer's voice; keeps no audio or transcripts by default. Orders from November, shipping by end 2026
Sandbar	Voice ring	—	$36M: $13M seed (Nov 2025), $23M Series A (Mar 2026)	—
Taya	Voice-note pendant	$89 pre-order	$5M seed (Mar 2026)	Founded by a former Apple engineer
Bee	Wrist-worn device	$49.99	Bought by Amazon (Jul 2025), price not disclosed	Amazon has since launched a new wrist device with Bee

What this means for us

Investors are funding this category now, at $5–36M per company. Our CHF 12–18M is in that range.
Nirva sells at $249; we would sit just above at CHF 349. Solid titanium, a sapphire stone, the replaceable module and the cuff format have to justify the difference.
Nirva ships with up to 3 days of battery, the same as our stone-only option.
Recording only the wearer and keeping no audio is becoming the expected privacy standard. We should match it.
Our piece weighs 23–25 g against Nirva's 8 g. A cuff is heavier by nature; comfort has to be proven in the wear test.

All figures are estimates for discussion. ≈ 1 USD = CHF 0.80 est.

14Start now: kit, 90 days, risks, open questions

Key point

About CHF 20–35k of kit lets us build a working module on a printed cuff within 75 days. The two risks to retire first are the attachment and iPhone background behaviour.

Kit to buy this week

Scroll the table sideways →

Item	Qty	Price found	Where	Why
Nordic nRF54L15-DK	2	$39.00	Mouser, Newark	Firmware, codec test
Seeed XIAO nRF54L15 Sense	4	$15.99	Seeed	Thumb-size board with mic for wrist tests
Raytac AN54LV-DB-15	2	€14.49	DigiKey marketplace	Ready radio module for early boards
Nordic PPK2 power profiler	2	£70.45 ex VAT	Farnell UK	Proves the battery claim
Nordic nPM1304-EK	2	$38.69	Future	Power chip tuning
TDK EV_T5838-FX2	4	≈ $36 est	Mouser, element14	Wake-on-sound, acoustic tests
Azoteq IQS7222A eval kit	2	≈ $7.6 est	Mouser	Touch through sapphire
Boréas BOS1901 kit + TDK PiezoHapt thin piezo samples	1	quote	Mouser / TDK	The clicking stone
Qorvo FT-7600 samples	5	quote	Qorvo	Press sensing
Grepow GRP1707026 and GRP2508030 cells	10 + 10	TC	Grepow	Fit, mass and battery tests for options A and B
Mill-Max Maxnetic pogo connectors	5	TC	Mouser	Dock prototype
Fallback haptics: PMD C08-00A, Adafruit DRV2605L	5 / 3	£5.85 (DRV2605L)	Precision Microdrives, Pimoroni	A/B against the piezo
LEDs (ROHM, LITEON) and DM-OLED042 test display	—	DM-OLED042 $2.90	DigiKey, DisplayModule	Light under smoked samples
Formlabs Form 4 + Tough 2000 resin	1	from $3,499	TriMech	Printed cuffs and module shells
Makera Carvera desktop CNC	1	€4,939.95	Makera EU	Brass cups, hooks and latch mock-ups
Bench: hot air, microscope, NanoVNA, force gauge, wrist phantom	—	CHF 2.5–4.5k est	—	Antenna and latch tests
Total		CHF 20–35k est

90-day plan

Window	Hardware	Software	Suppliers, people, legal
Days 1–14	Order the kit, printer and resin	Week 2: Opus vs LC3 codec current on the dev kit; pick one	NDAs and quotes: EEMB and Grepow (cells), Stettler (5 tints), Cicor and Dyconex, Positive Coating, MRP / Queloz (prototype cuff, module shell, latch); Boze Titanium and two other Asian case makers (production quotes). Hire: hardware lead, firmware, jewellery CAD designer
Days 15–45	Wrist prototype on the XIAO board. Brass cup, hook, magnet and latch mock-ups on the desktop CNC; pull and cycle tests	Week 3 go/no-go: locked iPhone, music playing, press, hear the answer. Full mAh/day table	Cuff CAD for S–XL with the standard oval cup; stone module CAD for options A and B. Counsel on recording law and the battery file
Days 46–75	Printed cuff set + printed stone modules (A and B) with real boards, Grepow cells and dock. One-week wear by 5 people	Pairing, light and click language, gesture tuning	Titanium quotes for 3 machined cups and capsules; start antenna simulation with Ignion
Days 76–90	Machined titanium cup and capsule: Bluetooth range on a wrist phantom; latch drop and sweat tests	Offline queue and signed updates	Review stone tints; pick PVD colour; shortlist test lab. Gate review: EVT plan and budget

Top risks

#	Risk	Odds / impact	Mitigation
1	Module released by accident or lost	Med / High	Two-action latch; test spec in section 05; last-seen location in the app; module replacement programme
2	iPhone background Bluetooth and locked-phone playback	High / High	AccessorySetupKit from day one; week-3 gate; notification fallback
3	Stone-only battery life (≈ 3 days typical) too short for clients	High / High	Prototype Option B in parallel; gesture-first capture; écrin top-up; decide after the P1 wear test
4	Recording law versus the hidden concept	Med / High	Gesture-first, visible glow during capture, counsel sign-off
5	Bezel antenna detuned by the titanium cup and the wrist	Med / High	Isolated titanium bezel; tune once on a master cuff; chip-antenna fallback; check each new cuff metal
6	The 4.0 mm stack does not close (thin custom cell, custom piezo)	Med / Med	Early quotes from Grepow and TDK; accept a 4.3 mm capsule if needed; stock-cell prototypes first
7	Sweat corrosion on pads, hook, inserts or latch	Med / Med	Thick gold pads live only on the dock; titanium latch parts; sweat and salt tests
8	Light under the stone unreadable in daylight	Med / High	LEDs, inner anti-reflection coat, five-tint trial
9	Module sealing and microphone membranes	Med / Med	Caseback-style O-ring; freeze the acoustic stack at EVT1
10	Lead times and single sources (chips, cell)	High / Med	Buy evaluation stock now; Grepow custom cell as second source

Open questions

Do clients accept charging every two to three days for the stone-only module, or do we choose Option B?
Bezel in gold-tone PVD or plain titanium?
Launch with one finish (natural titanium) or two (plus black)?
Sell a second module as an option for owners who never want to wait for charging?
Does the stone ever show text or the time? If yes, a small display and a Watch Ordinance opinion are needed.
EEMB: UN38.3 report, discharge rate, minimum order and a custom 3.0 mm cell.
Which Asian titanium case maker and EMS take a first order of 1,000–2,000 sets, and at what set-up cost?
Pairing without a six-digit display: is numeric comparison on the phone enough for EN 18031?
Is a wake word needed? Only then consider a chip with a neural accelerator.

15Glossary

BOM: Bill of materials: the list of every part and its cost.
SoC: System on chip: the main chip, here with the Bluetooth radio built in.
PMIC: Power management chip: charges the battery and supplies the other chips.
BLE: Bluetooth Low Energy, the low-power link between module and phone.
A2DP / LE Audio: Bluetooth ways to send music-quality audio to headphones; the phone does this, not the module.
PDM microphone: A tiny digital microphone chip.
Piezo / LRA: Two ways to make a click or buzz: a piezo element moves very fast and very little; an LRA is a small vibration motor.
Dead-front: A surface that looks plain when off and shows light only when lit.
HDI board: A very dense, thin circuit board with tiny laser-drilled connections.
Pogo pins: Spring-loaded contacts, here in the dock.
Bezel: The metal rim that holds a stone; here it is also the antenna.
Cabochon: A stone polished into a smooth dome, without facets.
IP68: Dust-tight and protected against continuous immersion in water.
EVT / DVT / PVT: Engineering, design and production validation: the three prototype stages before mass production (MP).
NRE: Non-recurring engineering: one-off set-up costs such as tooling and fixtures.
MOQ: Minimum order quantity a supplier accepts.
Landed cost: Cost of one unit delivered to us, including parts, assembly, yield loss and freight.
UN38.3 / IEC 62133-2: Mandatory safety tests for lithium cells: transport and product safety.
CE / RED / FCC: EU and US approvals for radio products.
EN 1811: EU test for nickel released by jewellery against the skin.
CNC / PVD / SLM: Computer-controlled machining; a hard thin colour coating; laser 3D printing of metal.
Zirconia: A hard, radio-transparent technical ceramic.

16Sources

Key point

All links cited by the eight specialist studies and the module update, de-duplicated. Distributor pages are snapshots; re-check prices and stock before ordering.

L'Atelier

In one minute

What it looks like

01The concept: permanent cuff, replaceable module

Why the stone is the module

What it costs us

Business model in short

02Specification

Decisions where the options disagreed

03System architecture

04How everything fits

4.0 General arrangement, to scale (size M)

4.1 Exploded view: stone module and cup

4.2 Stone module seen from above

4.3 Cross-section

4.4 On the wrist

4.5 Option B: more battery under the band

4.6 Volume budget of the capsule

4.7 Weight budget, size M

4.8 Strength of the cuff

05Attachment

Design rules

Test requirements

06Bill of materials

Enclosure parts per unit

07Cuff, module housing and stone

Materials and finishes

The stone

Antenna

Sealing (module only)

08Battery and charging

Cell candidates

Power draw (from the earlier power study, unchanged electronics)

Battery life

Dock

EU Battery Regulation

09Stone interface, firmware, app and audio

The stone

Firmware

Audio path to the headphones

Built-in speaker: not in v1

Phone and cloud

Privacy and the law

10Make, customise or buy

11Suppliers directory

12Manufacturing, cost, pricing and timeline

Supply chain

Certification

Cost per set

Pricing

Timeline

13Funding: what we need to raise

How accurate are these prices?

Budget to the first customer (months 0–24)

After launch, to break-even

Three rounds

Other money besides equity

Comparable companies

14Start now: kit, 90 days, risks, open questions

Kit to buy this week

90-day plan

Top risks

Open questions

15Glossary

16Sources

Silicon, radio and sensors

Power and charging

Display, touch and haptics

Enclosure and materials

Mechanical integration and PCB

Software, cloud, privacy and law

Manufacturing and certification

Prototyping tools and partners

Funding and market

Module cells (update)