A wrist-worn millimetre-wave radar that detects people in the space in front of you — where there is no fixed sensor and no infrastructure to rely on. Built on the LILYGO T-Watch Ultra reference design with one radar added.
SENSOR COVERAGE, DRAWN TO SCALE · 100° × 5 m
Earlier versions of this page advertised 100 m through-wall detection, RFID reading at 500 m, a custom ML-accelerated processor and a set of certifications the product does not hold. A full engineering and regulatory review found that none of those claims can be supported, and several are physically impossible at 60 GHz. They have been removed.
What remains below is what a wrist-worn millimetre-wave sensor can actually do, with the measurement or the statute behind each figure. The full workings — physics, bill of materials, manufacturing routes and certification path — are published in the engineering and cost analysis.
No conformity assessment is complete. Nothing on this page may be read as a certification claim.
Every figure below is a datasheet number or a published measurement, derated for a sensor worn on a moving wrist rather than bolted to a ceiling.
A 60 GHz pulsed coherent radar with the antenna inside the chip package. Reports whether someone is in its field, which zone they are in, and whether the motion is fast or slow. Reliable to 5 m from the wrist; the bench figure for the bare sensor is 7 m.
Chest-wall movement is about 3 mm and readable. Set the watch on a surface, 0.3–1.5 m from a still subject, and it recovers breathing rate to roughly 0.5–2 breaths per minute. Worn and moving, the measurement does not survive — your wrist moves ten times further than the signal.
The sensor averages about 3 mW at a 10 Hz update rate and draws 43 mA from the cell at full rate. On the 1100 mAh battery that is 18.5 hours of continuous sensing, or a full 24-hour day at 73% duty cycle. Alternatives in the same class draw 6–12× more.
A ceiling sensor is better than this device in any room that has one. The case for wearing it is mobility: a lone worker moving through a plant, a responder in a building with no infrastructure, a carer walking rounds. That is the whole argument, and we do not stretch it further.
An Espressif ESP32-S3 running the Acconeer radar service alongside an LVGL interface. No custom silicon, no encrypted bytecode, no claims about firmware that cannot be extracted. The signal chain is documented so a buyer's own engineer can check it.
Every specification traces to a manufacturer datasheet, a federal ordinance, a distributor price list or arithmetic we show. Where a figure is our estimate, it says so. The full analysis, including the parts that are unflattering, is published.
Not Wi-Fi, and not through walls. A dedicated millimetre-wave sensor illuminating the space directly in front of you.
A wavelength of 4.96 mm, radiated at about 11 dBm from an antenna built into the 5.5 mm chip package. It travels through air and clothing, and stops at walls and bodies.
A person reflects the pulse. Because the sensor is coherent it measures the phase of that echo, so movements far smaller than the wavelength show up as a phase change.
On-device processing separates a living body from a static reflection by its motion — including the small, regular motion of breathing. No cloud, no upload, no image.
Because the returned signal is a range and a motion, not a picture, the device cannot identify a person, see an object's shape, or tell what someone is carrying. That is a property of the physics, not a limitation of this version.
Reference design plus one sensor
Dimensions are those of the LILYGO T-Watch Ultra reference design and will change once our board is laid out. No device weight is published by the manufacturer, so we do not quote one.
The device is pre-certification. We are placing a small number of units with pilot partners who need presence sensing where no fixed sensor exists.
Indicative only · no unit may ship before CE conformity is complete
No payment is taken at enquiry. Pilot pricing is confirmed in writing once the certification timetable is fixed.