The GUVA-S12SD is a small sensor that turns UV light into a voltage you can read with an Arduino Nano's analog input. No library needed, just analogRead() and a bit of math to turn the raw number into an approximate UV index, the same kind of number weather apps show you. It's a nice weekend build if you want a sense of how exposed to sun you actually are, not just how bright it looks outside.

The full tutorial, with every detail and the line-by-line code explanation, is on our site: Arduino Nano - GUVA-S12SD UV Sensor

What you need

Official Arduino Nano

DIYables Nano V3.0 Development Board

USB A to Mini-B USB cable

Breadboard

Jumper Wires

Screw Terminal Expansion Board for Arduino Nano

Breakout Expansion Board for Arduino Nano

Power Splitter for Arduino Nano

DIYables Sensor Kit (18 sensors/displays)

Wiring

The module has three pins: SIG, GND and VCC. Connect VCC to the 3V3 pin on the Nano (5V also works, since the module accepts 2.5V to 5V), GND to GND, and SIG to analog pin A0.…