Battery-free optical tag based on STM32L0 and BlueNRG-2

The STDES-BFTAG01 is an energy autonomous and battery-free wireless sensor.
[STDES-BFTAG01 IMAGE]
The companion STPVTAG app is available for free download on Google Play.
The device implements off-the-shelf components (2 x 2~cm PCB, 4 mm thickness, weight <5 grams).
It features Bluetooth low energy (BLE) communication and can harvest and sense indoor ambient light with a limit of detection of 200~lux.
The board is energetically autonomous thanks to a photovoltaic transducer that simultaneously provides power and light sensing functionality, together with time domain read-out.
The number of tag transmissions to a remote base station, in a given time interval, proportionally varies in relation with light intensity, that is, more light is equal to more frequent broadcasts.
Therefore, the battery-free tag expresses light intensity as a function of time and this phenomenon can be exploited by the base station to convert transmission intervals into accurate expressions of light intensity.
The same concept can be extended to other sources of ambient energy, such as kinetics, thermal, etc.

所有功能
Wireless energy autonomous light sensor
Limit of detection > 200 lux
Bluetooth low energy communication
Communication range: 5 meters
Tag size: 2 cm x 2 cm
Tag thickness: < 4 mm
Tag weight: < 5 g
Radio activity control
Advertising time control
Over-the-air configuration