One continuous gesture.
A gently curved jacket replaces the exposed centre seam. Narrow, colour-matched shoulders finish the edges without adding a crown.
A2 CONTINUOUS BAND · ENGINEERING
PREVIEW
Small by design.
Open by nature.
Health sensing. A moment of voice. Your own firmware.
A
considered band, with an entire world inside.
An interactive view of a real design in development.
Not a
released consumer product.
Pearl / finish study
19.0mmInner diameter
10.2mmBand width
4.05mmRadial thickness
39Fitted components
Current CAD dimensions.
One prototype size; fit variants are
future work.
DESIGN / M4
Made to feel
more personal.
A quieter silhouette. Softer edges. A continuous outer jacket with the assembly seam tucked beneath. The engineering stays inside a band.
A softer way on.
The 19 mm bore opens to 19.9 mm at entry, with real 0.12 mm edge radii. Flush optical windows and side charging contacts preserve the uninterrupted band.
Less visual noise.
A curved, seven-hole microphone guard follows the surface. Pearl, Graphite and Sand use a nonconductive finish over a PC jacket; these are colour studies, not metal or ceramic shells.
Refined around the real electronics. 27.1 mm outside diameter · 10.2 mm width · 4.05 mm radial thickness. The 9 mm flex board limits further slimming. One prototype size is modelled; a size range requires new fit studies.
CAD + design dossier ↓Nominal geometry checks pass. Comfort, scratch resistance, skin compatibility, acoustics and sealing still require physical samples and testing.
01 / THE EXPERIENCE
Technology, quietly
within reach.
A band for the moments that matter. Explore what the hardware is designed to do—and where the engineering stands today.
A closer look at your signals.
Optical sensing, motion and temperature in one band. Inspect raw signals before turning them into application logic.
Explore sensor signals ↗Raw telemetry · no validated heart-rate or SpO₂ algorithmA moment, on your terms.
Short microphone clips start with local button consent. The firmware limits recording to five seconds and lights the recording indicator.
Try consent & recording ↗PDM microphone · 16 kHz mono PCM · no always-listening modeYour ring. Your logic.
Program over SWD, connect over encrypted BLE, and develop your own applications on the nRF52833 platform.
Explore the developer kit ↗Editable C / Zephyr firmware · OTA is not implemented02 / THE DIGITAL TWIN
Nothing to hide.
Everything to explore.
Rotate the native CAD. Separate the assembly. Follow a component from the band to the circuit. Every solid comes from the current design.
Native Gerber · 49.314 × 9 mm
Actual routed copper, vias and mask. Select a component in the inspector to see its placement and connected nets.
A2 BAND / M4 HOUSINGDRAG TO ORBIT · SCROLL TO ZOOM
↳ Geometry twin: real CAD, component envelopes and nominal fit. Not a structural, thermal or electromagnetic solver.
Download 3D model ↓
M3 / EXPLODED OPTICAL ASSEMBLY
A SMALL DETAIL. A MEANINGFUL DIFFERENCE.
Two windows.
One clear purpose.
The detector and LEDs have separate optical paths. A full-depth opaque divider and a seal against the sensor face remove the shared clear-window path.
0.24 mmOpaque divider
0.34 mmClear-window separation
Nominal geometry verified. Material opacity, crosstalk and sealing require physical tests.
03 / THE LIVE LAB
Don’t just look.
Put it to the test.
Run the real C application policy in WebAssembly. Explore synthetic signals, change assumptions, and see exactly how the design responds.
LOADING C FIRMWARE…
The actual state machine.
Change virtual inputs. Grant simulated button consent, then start a clip or a health window. The same C policy used by the firmware makes the decision.
No microphone is accessed. Radio, sensors, ADC and the RTOS are not emulated. Worn-state detection is a virtual input, not an implemented physical feature.
APPLICATION POLICY / LIVE00:00.0
CURRENT STATELoadingConsent not granted
STATUS / 12 BYTES / LITTLE ENDIAN
—
EVENT TRACE
SYNTHETIC SIGNAL GENERATOR
See the signal, before the insight.
These generated waveforms illustrate raw red/IR, motion and temperature telemetry. They are not readings from a person or a physical ring.
Hear a synthetic PCM clip
16 kHz · 16-bit mono · 2 seconds. A generated tone, not recorded speech.
Download WAV ↓
RED / IR RAW COUNTSILLUSTRATIVE
Red · 660 nmIR · 880 nm
RED COUNTS—
IR COUNTS—
TEMPERATURE—
ACCEL Z / RAW—
Signal amplitudes are illustrative. No calibrated reflectance, oxygen saturation, heart-rate accuracy or medical interpretation is modeled.
EDITABLE PLANNING MODEL
Every moment has an energy cost.
Explore the trade-off between sensing, audio and battery life. All current values here are assumptions; replace them with power-analyzer measurements.
Edit current assumptions
ESTIMATED RUNTIME · NOT MEASURED
60.6hours
0.191 mA average · 80% usable capacity
runtime = capacity × usable fraction ÷ average current
Includes a fixed base allowance and incremental PPG/audio duty. Concurrent load peaks, cell discharge limits, RF retries, temperature, aging and converter efficiency are not separately solved.
GRP170722 14.5 mAh is a candidate, not an ordered battery. Changing this slider does not change the CAD cavity. Final battery and charging limits need supplier confirmation.
GEOMETRIC TOLERANCE STUDY
Small margins. Visible consequences.
Inspect alignment and contact tolerances. These arithmetic checks do not simulate optical propagation, seal force or electrical contact resistance.
Optical registration budget: 0.08 mm. Seal gap process target: 0.15–0.50 mm. Pogo design height: 3.00 ±0.05 mm; component travel limits: 2.85–3.10 mm.
Alignment schematic, exaggerated for visibility; use the CAD viewer for exact geometry.
DEVELOPER WORKBENCH
Every byte, explained.
Decode the ring’s 32-byte health packet. Generate an example or paste your own hex; only fields marked valid are interpreted.
Ready for a packet.Download protocol specification ↓
OPTIONAL PHYSICAL HARDWARE
Bring a real ring,
Bring a real ring,
when it’s ready.
Web Bluetooth can connect to a compatible programmed A2Band prototype. Pairing and notifications require browser and operating-system support.
Not connected · no physical prototype tested
Device status and health telemetry appear here.
This connector reads Status and subscribes to Health. It does not bypass encryption, simulate a physical button, start a microphone, flash firmware or claim a successful hardware test. Chromium desktop/Android typically offers Web Bluetooth; other browsers may not.
EXECUTES THE COMPILED C CORE
Test the decisions that matter.
Fresh WebAssembly instances. Deterministic inputs. Actual assertions. These are software policy tests, not a physical ring certification.
Tests have not run in this browser session.
04 / ENGINEERING, IN THE OPEN
See the work.
Know the limits.
The current build has passed digital checks. Five functional wearable prototypes remain the next milestone. There are no validated physical rings yet.
Open PCB connections
Ring and dock routing checks pass. Native DRC and schematic ERC report zero violations.
RECORDED DIGITAL CHECK · 21 OCT 2026Native firmware test suites
Application policy, optical driver and MAX30102 shutdown tests run against the C code with host-side mocks.
Read the build-time test output ↗Separate optical windows
CAD separation and a continuous opaque bridge pass geometric checks. Real optical and seal performance remain unmeasured.
Download engineering evidence ↗A purpose-built component stack.
| Ref | Component | Placement | Connected nets |
|---|
39 fitted positions. Exact-part allocation and complete five-unit / 1,000-unit costs remain unquoted. No price or availability promise is made.
BUILD YOUR OWN APPLICATION
Start with the source.
189,676 bytes of flash. 50,260 bytes of RAM. A Zephyr application with editable logic, SWD programming and encrypted BLE transport.
Engineering files are development references, not a fabrication release. Firmware core downloads contain policy logic; the full hardware application is not emulated in the browser.
ARZEN / RING LAB
A small object.
A world to build.
Back to the live lab ↗
A2 band · M4 housing · D2 dock
Built for understanding,
experimentation and the next prototype.