SparkFun
SparkFun Spectral UV Sensor - AS7331 (Qwiic)
This SparkFun Qwiic Spectral UV Sensor features the AS7331 UV sensor from ams OSRAM©. It measures UV radiation on three channels: UVA (320-400nm), UVB (280-3...
This SparkFun Qwiic 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. The sensor has four 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 breakout routes the I2C bus pins (3.3V, GND, SDA, and SCL) to a pair of Qwiic connectors on each side of the board for solderless assembly but also routes them 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.
Features:
- 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
Documents:
- Schematic
- Eagle Files
- Board Dimensions
- Hookup Guide
- Datasheet (AS7731)
- Qwiic Info Page
- SparkFun AS7331 Arduino Library
- GitHub Hardware Repo
Videos
Jargon buster
Plain-language definitions for the technical terms used above.
- AS7331
- A sensor chip designed to measure ultraviolet light in separate UVA, UVB and UVC bands. The part number matters because it tells you which libraries, datasheets and measurement capabilities apply to this breakout board.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine 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.
- PCB
- A printed circuit board is a rigid board with copper tracks that connect electronic parts without loose wires. For this kit, the PCBs also form the airplane shape, so they are both the circuit base and part of the finished model.
- photodiode
- A photodiode is a light-sensitive electronic component that produces a signal when light hits it. In this sensor, multiple photodiodes let the chip measure different parts of the light spectrum 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.
- 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
SparkFun Qwiic UV Sensor AS7331 Schematic
Schematic · 101.8 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 · 745.3 KB · Click any page to view full size
Resources & Downloads
Guides, code examples, and more
Related Tutorials
Free guides on learn.littlebird.com.au
