---
product_id: 521562002
title: "LTR390 UV Light Sensor - Stemma QT/Qwiic Ada 4831"
brand: "adafruit"
price: "€ 16.85"
currency: EUR
in_stock: true
url: https://www.desertcart.ie/products/521562002-ltr390-uv-light-sensor-stemma-qt-qwiic-ada-4831
store_origin: IE
region: Ireland
---

# UVA sensing 300-350nm I2C interface Breadboard compatible LTR390 UV Light Sensor - Stemma QT/Qwiic Ada 4831

**Brand:** adafruit
**Price:** € 16.85
**Availability:** ✅ In Stock

## Summary

> 🌈 Illuminate Your UV Awareness!

## Quick Answers

- **What is this?** LTR390 UV Light Sensor - Stemma QT/Qwiic Ada 4831 by adafruit
- **How much does it cost?** € 16.85 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ie](https://www.desertcart.ie/products/521562002-ltr390-uv-light-sensor-stemma-qt-qwiic-ada-4831)

## Best For

- adafruit enthusiasts

## Why This Product

- Trusted adafruit brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **🚀 Ready to Use:** Breakout PCB with Stemma QT for easy testing.
- • **🌟 Real UV Sensing:** Experience true UV light measurement for sun safety.
- • **⚡ Effortless Integration:** Seamlessly connect with Arduino and Raspberry Pi.
- • **🔍 Precision Performance:** Accurate ambient light and UVA readings.
- • **🧩 Versatile Compatibility:** Works with both 5V and 3.3V systems.

## Overview

The LTR390 UV Light Sensor is a low-cost, high-performance device designed for accurate UVA and ambient light sensing. With a peak spectral response between 300 and 350nm, it offers true UV measurements, unlike other sensors that approximate UV Index. Its simple I2C interface allows for easy integration with popular microcontrollers, making it ideal for both hobbyists and professionals. The sensor comes on a breakout PCB in the Stemma QT form factor, ensuring compatibility with various systems and ease of use.

## Description

The LTR390 is one of the few low-cost UV sensors available, and it's a pretty nice one! With both ambient light and UVA sensing with a peak spectral response between 300 and 350nm. You can use it for measuring how much sun you can get before needing to covering up. Unlike the Si1145, this sensor will not give you UV Index readings. However, the Si1145 does UV Index approximations based on light level not true UV sensing. The LTR-390, in contrast, does have a real light sensor in the UV spectrum. It's also got a much much simpler I2C interface so you can run it on the Arduino or Python microcontrollers/microcomputers with ease. Unlike the GUVA analog sensor, the biasing and ADC is all internal so you don't need an ADC. To make using it as easy as possible, we’ve put the LTR390 on a breakout PCB in our Stemma QT form factor with a sprinkle of support circuitry to give you options when testing. You can either use a breadboard or the SparkFun qwiic compatible STEMMA QT connectors, and compatibility with 5V voltage levels as commonly found on Arduinos, as well as 3.3V logic used by many other boards like the Raspberry Pi or our Feathers. QT Cable is not included, but we have a variety in the shop for quick plug-and-play support.

## Features

- The LTR390 is one of the few low-cost UV sensors available, and it's a pretty nice one! With both ambient light and UVA sensing with a peak spectral response between 300 and 350nm. You can use it for measuring how much sun you can get before needing to covering up.
- Unlike the Si1145, this sensor will not give you UV Index readings. However, the Si1145 does UV Index approximations based on light level not true UV sensing. The LTR-390, in contrast, does have a real light sensor in the UV spectrum. It's also got a much much simpler I2C interface so you can run it on the Arduino or Python microcontrollers/microcomputers with ease. Unlike the GUVA analog sensor, the biasing and ADC is all internal so you don't need an ADC.
- To make using it as easy as possible, we’ve put the LTR390 on a breakout PCB in our Stemma QT form factor with a sprinkle of support circuitry to give you options when testing. You can either use a breadboard or the SparkFun qwiic compatible STEMMA QT connectors, and compatibility with 5V voltage levels as commonly found on Arduinos, as well as 3.3V logic used by many other boards like the Raspberry Pi or our Feathers. QT Cable is not included, but we have a variety in the shop for quick plug-and-play support.

## Images

![LTR390 UV Light Sensor - Stemma QT/Qwiic Ada 4831 - Image 1](https://m.media-amazon.com/images/I/71gCuqAO9mL.jpg)
![LTR390 UV Light Sensor - Stemma QT/Qwiic Ada 4831 - Image 2](https://m.media-amazon.com/images/I/81Kge+VCvNL.jpg)
![LTR390 UV Light Sensor - Stemma QT/Qwiic Ada 4831 - Image 3](https://m.media-amazon.com/images/I/71iFHXnCYcL.jpg)
![LTR390 UV Light Sensor - Stemma QT/Qwiic Ada 4831 - Image 4](https://m.media-amazon.com/images/I/618srN9LcsL.jpg)
![LTR390 UV Light Sensor - Stemma QT/Qwiic Ada 4831 - Image 5](https://m.media-amazon.com/images/I/81nO+Wrz9LL.jpg)

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---

*Product available on Desertcart Ireland*
*Store origin: IE*
*Last updated: 2026-02-25*