1. The transponder (Finkenzeller, 2003) that was designed to perform
data reception and transmission from the reader and to
obtain the supply voltage from the 13.56 MHz signal. This transponder
consists of several electronic components and an
antenna. The antenna (38 mm 54 mm) is was composed of
a seven-turn spiral-shaped inductor, track thickness of 18 lm,
track width of 300 lm and spacing between two tracks of 300
lm, and a parallel trimmable plate capacitor to tune the frequency
to the 13.56 MHz.
2. The temperature and humidity commercial sensor SHT15 (Sensirion,
Switzerland) was selected for this application. This product
is a single chip comprising a calibrated digital output
(accuracy of ±0.4 @ 5–40 C). The sensor needs to be powered
between 2.5 V and 5.5 V.
3. A light sensor having a spectral range between visible and IR
with a small footprint. For this reason a photodiode SLCD61N1
(Silonex, Canada) was chosen. It provides an interrupt to microcontroller
in case of the light exceeds the alarm limit, for
instance, if the box product is opened.