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# Adafruit LTR390 UV Light Sensor - STEMMA QT / Qwiic

**Type:** Product page · **SKU:** ADA4831 · **Brand:** [Adafruit](https://core-electronics.com.au/brands/adafruit-australia)
**Page:** https://core-electronics.com.au/adafruit-ltr390-uv-light-sensor-stemma-qt-qwiic.html ([markdown](https://core-electronics.com.au/adafruit-ltr390-uv-light-sensor-stemma-qt-qwiic.html.md))

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.

## Pricing

- **Price:** $8.80 (inc GST) — $8.00 AUD, exc GST
- **Quantity discounts:** 10+ $7.76 (exc GST) · 50+ $7.60 (exc GST)

## Availability & dispatch

- In stock, ships same business day if ordered before 2PM (Australia/Sydney).
- We can dispatch 3 today, and up to 500 more in 7–12 days.

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## 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](https://core-electronics.com.au/si1145-digital-uv-index-ir-visible-light-sensor.html), 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](https://core-electronics.com.au/analog-uv-light-sensor-breakout-guva-s12sd.html), 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](https://www.adafruit.com/?q=Stemma+QT+Sensor) with a sprinkle of support circuitry to give you options when testing. You can either use a breadboard or the[ **SparkFun qwiic**](https://www.sparkfun.com/qwiic) compatible [**STEMMA QT**](https://learn.adafruit.com/introducing-adafruit-stemma-qt) connectors, and compatibility with 5V voltage levels as commonly found on [Arduinos](https://www.adafruit.com/category/17), 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](https://core-electronics.com.au/search/?q=stemma+qt) for quick plug-and-play support.

### Resources

Adafruit have an [excellent guide](https://learn.adafruit.com/adafruit-ltr390-uv-sensor) that walks you through using this sensor.

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/4/8/4831-00.jpg)