SparkFun
SparkFun Mini Spectral UV Sensor - AS7331 (Qwiic)
· MPN: SEN-23518
The SparkFun Mini Spectral UV Sensor features the AS7331 from ams OSRAM, measuring ultraviolet radiation across three dedicated channels: UVA (320–400 nm), U...
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The SparkFun Mini Spectral UV Sensor features the AS7331 from ams OSRAM, measuring ultraviolet radiation across three dedicated channels: UVA (320–400 nm), UVB (280–320 nm), and UVC (200–280 nm). Each channel has its own photodiode with built-in interference filter for high sensitivity and accuracy.
This Qwiic Mini breakout (1 × 0.5 in.) communicates over I²C and includes two Qwiic connectors for solderless daisy-chaining, plus a 0.1"-spaced through-hole header with Interrupt and Sync pins. An Arduino library is available for quick setup via the Library Manager — search for "SparkFun AS7331".
Key Features
- Three UV Channels – UVA, UVB, and UVC with dedicated photodiodes and interference filters
- Four Operating Modes – Single Measurement (CMD), Continuous (CONT), Synchronized Start (SYNS), and Synchronized Start/End (SYND)
- High Dynamic Range – Up to 3.43×10¹⁰ (resolution × gain range)
- Ultra-Low Power – 1.42 mA active, 970 µA standby, 1 µA power-down with automatic power-down between measurements
- Qwiic I²C Interface – 2× Qwiic connectors for solderless assembly, plus through-hole header
- Four I²C Addresses – 0x74 (default), 0x75, 0x76, 0x77 via A0/A1 solder jumpers
- Compact Form Factor – Qwiic Mini footprint at just 1 × 0.5 in.
Specifications
- Sensor – ams OSRAM AS7331
- Operating Voltage – 2.7 V to 3.6 V
- Current (Active) – 1.42 mA typical
- Current (Standby) – 970 µA
- Current (Power Down) – 1 µA
- Interface – I²C (Qwiic compatible)
- Board Size – 1 × 0.5 in.
Ideal For
- UV index monitoring and environmental sensing
- UV sterilisation effectiveness measurement (UVC)
- Wearable sun exposure tracking
- Scientific and industrial UV analysis
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- AS7331
- The AS7331 is an ams OSRAM sensor chip that measures ultraviolet light across separate UVA, UVB and UVC bands. The part number tells you which libraries, datasheets and measurement capabilities apply, since software support and behaviour are tied to that specific chip.
- breakout
- A breakout board carries a small or fine-pitched component and brings its connections out to standard, breadboard- and header-friendly pins. Describing a part as a breakout means it can be wired into a project without soldering directly to the component's tiny contacts.
- dynamic range
- Dynamic range describes how wide a span of values a sensor can measure, from very low to very high. For a light sensor, a wide dynamic range means it can work in dim indoor settings as well as bright sunlight without changing hardware.
- photodiode
- A photodiode is a light-sensitive component that produces a small electrical signal, a current or voltage, when light falls on it. When a sensor uses several photodiodes, each can be tuned to a different part of the spectrum so the chip can measure several wavelength bands separately.
- Qwiic
- Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
- through-hole
- A mounting style where the component leads pass through holes in a circuit board and are soldered on the other side. Through-hole parts are often easier to handle and solder by hand, which is useful for classroom and hobby projects.
- Torque
- A twisting force that causes something to rotate, usually measured in newton-metres or kilogram-centimetres. It matters when choosing motors, servos, gears, and tools because higher torque is needed to lift heavier loads, turn larger wheels, or move mechanisms without stalling.
- UVA
- UVA is the longer-wavelength part of ultraviolet light, closest to visible violet light. Measuring it separately matters when you need to distinguish general UV exposure from the more energetic UVB and UVC bands.
- UVB
- UVB is a middle band of ultraviolet light that is more energetic than UVA and is important in sun exposure and plant-related UV monitoring. A sensor with a separate UVB channel lets you measure this band without it being mixed together with other UV light.
- UVC
- UVC is a short-wavelength, high-energy band of ultraviolet light often used in germicidal lamps and curing applications. A separate UVC reading matters if your project needs to monitor or verify UVC sources rather than just detect general UV light.
Find this product in
Sensors & Input
SparkFun Qwiic Mini UV Sensor AS7331 Schematic
Schematic · 101.3 KB · Click any page to view full size
AS7331 Datasheet
Datasheet · 2.2 MB · Click any page to view full size
Supplier page — sparkfun.com
Supplier Description · 671.9 KB · Click any page to view full size
Resources & Downloads
Guides, code examples, and more
Source Code
Open-source libraries, firmware & example projects for this product
Arduino library for the SparkFun AS7331 Qwiic Spectral UV Sensor, which measures UV radiation on three channels, UVA, UVB, and UVC, with high sensitivity and accuracy.
3e22fb4
over 1 year ago
· 62 commits
- .github wrong toolkit name - grrr over 1 year ago
- docs make inherited members visible on arduino class over 1 year ago
- examples modifications to move to toolkit v1.0; updates to naming scheme and dir structure of independant section of code over 1 year ago
- src move to updated toolkit api; tweaks to call parameters for toolkit over 1 year ago
- .gitattributes Add library files. over 2 years ago
- .gitignore Add library files. over 2 years ago
- .gitmodules enable /setup initial doxygen for github pages files over 1 year ago
- keywords.txt Merge branch 'main' into work over 2 years ago
- library.properties fix version over 1 year ago
- LICENSE Initial commit almost 3 years ago
- README.md better doc link over 1 year ago
he SparkFun Spectral UV Sensor - AS7331 (Qwiic) measures UV radiation on three channels
b1354e6
30 days ago
· 25 commits
- .github fix mkdocs checkout 30 days ago
- docs Merge branch 'main' of https://github.com/sparkfun/SparkFun_Spectral_UV_Sensor_AS7331 over 2 years ago
- Documentation Update datasheet to latest. almost 3 years ago
- Hardware Pushing to v10 almost 3 years ago
- overrides Deploy Fix 2 over 2 years ago
- Production Remove unneeded folders and add production files. almost 3 years ago
- .gitattributes Initial commit almost 3 years ago
- .gitignore Initial commit almost 3 years ago
- CONTRIBUTING.md Initial commit almost 3 years ago
- ISSUE_TEMPLATE.md Initial commit almost 3 years ago
- LICENSE.md Initial commit almost 3 years ago
- mkdocs.yml Update mkdocs.yml 30 days ago
- README.md Deploy Fix 3 over 2 years ago
Related Tutorials
Free guides on learn.littlebird.com.au