SparkFun Mini Spectral UV Sensor - AS7331 (Qwiic)

This SparkFun Qwiic Mini Spectral UV Sensor features the AS7331 UV sensor from ams OSRAM©. It measures UV radiation on three channels: UVA (320-400nm), UVB (280-320nm), and UVC (200-280nm) with high sensitivity and accuracy. The three channels on the AS7331 each have individual photodiodes with built-in interference filters. This Mini-sized breakout board is only 0.5in. by 1in. big and has three operating modes: Single Measurement (CMD), Continuous Measurement (CONT), SYNchronized Start (SYNS), and SYNchronized Start & End (SYND), with an automatic power-down sequence between measurements for low current consumption in all three modes.

The AS7331 communicates over I2C, so naturally, this mini breakout routes the I2C bus pins (3.3V, GND, SDA, and SCL) to a Qwiic connector for solderless assembly but also routes it to a 0.1in.-spaced through-hole header on the bottom of the board for users who prefer a soldered connection. This header also includes the sensor's Interrupt and Sync pins. The AS7331 has four I2C addresses (default: 0x74) set by adjusting the A1 and A0 solder jumpers on the back of the board.

We've written an Arduino library to make it simple to quickly get started configuring the AS7331 and receiving UV radiation data from the sensor. Download it through the Arduino Library Manager tool by searching for 'SparkFun AS7331' or download it from the GitHub repository linked in the Documents tab.


The SparkFun Qwiic Connect System is an ecosystem of I2C sensors, actuators, shields and cables that make prototyping faster and less prone to error. All Qwiic-enabled boards use a common 1mm pitch, 4-pin JST connector. This reduces the amount of required PCB space, and polarized connections mean you can’t hook it up wrong.


  • Operating Voltage: 2.7V-3.6V
  • Current Consumption:
    • Active Measurement: 1.42mA (Typ.)
    • Standby Mode: 970µA
    • Power Down Mode: 1µA
  • Three UV Channels: UVA, UVB, & UVC
    • Each with dedicated photodiode
  • Four Operating Modes:
    • Single Measurement
    • Continuous Measurement
    • Synchronized Start Measurement
    • Synchronized Start/Stop Measurement
  • High Dynamic Range: Up to 3.43E+10 (resolution multiplied by gain range)
  • 2x Qwiic Connectors
  • Four Adjustable I2C Addresses
    • Set through A0 & A1 pins
    • 0x74 (Default), 0x75, 0x76, & 0x77
  • Qwiic Mini Footprint: 1in. X 0.5in.

SparkFun Mini Spectral UV Sensor - AS7331 (Qwiic) Product Help and Resources

Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

2 Programming

Skill Level: Rookie - You will need a better fundamental understand of what code is, and how it works. You will be using beginner-level software and development tools like Arduino. You will be dealing directly with code, but numerous examples and libraries are available. Sensors or shields will communicate with serial or TTL.
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Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

2 Electrical Prototyping

Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements. You will need to understand polarized components.
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Customer Reviews

5 out of 5

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Easy to start taking data.

Awesome easy. Good code examples that are easy to transform into something for your own use.

Fun to disprove common widsom

Guess what? 80% of UV rays make it through clouds is a pearl of wisdom that you hear sometimes, but it's way off. If you can't see your shadow, it's more like 20%.