Considering the importance of the sun, it is forgivable that our ancestors regarded it as God. Even now that we know what it really means and how it works, we are unlikely to think that the sun will release evil souls, which will bring disease and death to those who have been bathed in the sun for a long time. So an amulet against evil ultraviolet rays is a perfectly reasonable project, right?
Like [mitxela], especially those more dazzling projects, this project is almost equivalent to electronic products and fine metal processing. Most of the following videos focus on metal products, which is a very charming thing. The shell of the amulet is made of brass and is suitable for CR2032 coin battery. The back of the amulet has threads. It is used as a battery cover and needs some strange turning. The shell is also plated with gold to prevent discoloration. When paired with the black welding mask of PCB, it also looks good.
In electronics, [mitxela] strives to keep the battery power as low as possible and make full use of available space. Attiny84 supports ttp223 capacitive sensing chip and veml6075 UV sensor. The touch sensor allows the wearer to wake up the amulet and cycle in UV mode, and mitxela understands that these modes are not exactly the same as those described on the sensor data sheet. This requires some software hackers, but in the end, the amulet does a good job in reporting the UV index, and it looks great in doing so.