Set it up with Home Assistant, Zigbee or Matter, find every answer, or write to the people who built it.
Setup
Bluetooth is always on for the app, updates and the BTHome broadcast. In addition the sensor runs one mode: BTHome by default, or Zigbee or Thread, switched in the app in about a minute.
No cloud, no hub, no account. BTHome v2 is an open standard (bthome.io).
Tested with Home Assistant ZHA.
1 Implemented to the specifications; certification pending. Apple, Google and Amazon are not tested.
No iPhone app yet. In BTHome mode, Home Assistant reads the sensor without any app.
FAQ
About 8½ hours of 200 lx a day, which is normal living-room light. Twice the light, half the time: 400 lx for about 4¼ hours does the same. A spot near a window is plenty.
Try your own room in the light calculator.
A full energy store lasts about 4 weeks (26–27 days) in complete darkness. A dark corner may need a USB-C top-up (5 V) now and then; USB-C is also handy for a quick start.
Long-term field data is still being collected: an indoor winter test is running right now.
No. The energy is stored in a lithium-ion capacitor, not a battery, rated for more than 50,000 cycles. There are no batteries to change.
Zigbee is tested with Home Assistant ZHA. Matter over Thread is tested with Home Assistant’s Matter server and an OpenThread border router; during the beta, Home Assistant needs a one-time certificate step. Apple, Google and Amazon are not tested and not certified yet: certification is pending.
No cloud, no account, no subscription: the sensor talks to your smart home locally and your data stays in your home. In BTHome mode you need no hub at all; Zigbee and Thread use the coordinator or border router your smart home already has.
Bluetooth LE indoors typically reaches 10–30 m. Home Assistant Bluetooth proxies (ESPHome, Shelly) extend the range. In Zigbee and Thread mode the sensor uses your mesh of mains-powered routers; the sensor itself is a sleepy end device.
Not yet: the app is for Android. In BTHome mode, Home Assistant reads the sensor without any app.
Every improvement reaches the sensor as a signed over-the-air update from the app. If anything goes wrong, the sensor rolls back automatically.
Every unit has its own Bluetooth passkey, printed on its label: there is no shared default password. The firmware is signed, and everything stays local.
In the app you can set a calibration offset against a reference instrument. See the full comparison.
With the removable adhesive strip in the box: on a wall, a window frame or a shelf. Indirect daylight or room light is perfect. Avoid direct sunbeams on the sensor, they warm the case and skew the temperature reading, and keep it away from radiators.
In Itingen, Switzerland, near Basel. Swiss made: Designed, built and shipped in Switzerland. Every unit is hand-tested and serial-numbered.
The case is produced in-house in Switzerland from ASA; making it ourselves lets us build small batches and improve the design between batches.
No customs: we ship within Switzerland and to Liechtenstein, which shares the Swiss customs area. Shipping is calculated at checkout from the real postage.
The hardware of this batch is final; the firmware keeps getting better. Every improvement reaches the sensor as a signed over-the-air update from the app, with automatic rollback if anything goes wrong.
Long-term field data is still being collected (an indoor winter test is running right now). Pioneers get a direct line to the engineers: issues get fixed fast. Early, not unfinished.
Yes. The volume discount applies to the whole order, in any mix: 3+ units −10 % (Trio), 5+ −15 % (Home), 10+ −20 % (House). Units above the stock are built to order and ship in 2–4 weeks. Shops and installers: apply as a dealer.
Downloads
Photo credits
Two models, one case, both powered by light. From CHF 79.