SKU: SENS-3166
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Adafruit AS7331 UV / UVA / UVB / UVC Sensor Breakout - STEMMA QT / Qwiic

₹3,599.00 (Inclusive of all taxes)
Out of Stock

The Adafruit AS7331 breakout is a high-precision spectral UV sensor module providing independent UVA, UVB, and UVC band measurements via I2C. Featuring STEMMA QT/Qwiic connectors, it offers plug-and-play compatibility with Arduino, Raspberry Pi, and other 3.3V/5V microcontroller platforms for environmental monitoring and safety applications.

Features

  • Independent measurement of UVA (320–400 nm), UVB (280–320 nm), and UVC (200–280 nm) spectral bands.
  • High sensitivity down to 2.38 nW/cm² per LSB with configurable gain and conversion settings.
  • I2C interface with default address 0x74, configurable for multi-device setups (up to 4 sensors).
  • STEMMA QT / Qwiic plug-and-play connectivity eliminates soldering for rapid prototyping.
  • Integrated READY output pin and SYNC input for synchronized, multi-sensor data acquisition.

Out of stock

Description

The AS7331 sensor utilizes a monolithic CMOS spectral sensing array with dedicated photodiodes for each UV band, enabling accurate separation and quantification of UVA, UVB, and UVC irradiance. This design prevents spectral crosstalk, providing reliable data for environmental analysis, material curing monitoring, and UV safety compliance. The onboard level shifter ensures compatibility with both 3.3V and 5V logic systems.

Communication is handled via a standard I2C interface, with programmable gain settings and conversion times allowing optimization for specific measurement ranges and sampling rates. The inclusion of READY and SYNC pins supports advanced timing control for synchronized data capture across multiple sensors, ideal for industrial or research-grade monitoring systems. Comprehensive Arduino and CircuitPython libraries streamline integration and data processing.

Key Features

  • Triple-channel spectral UV sensor with independent UVA, UVB, and UVC photodiodes.
  • High dynamic range measurement: UVA up to 349 mW/cm², UVB up to 386 mW/cm², UVC up to 169 mW/cm².
  • Configurable gain and internal 24-bit ADC resolution for precise low-light detection.
  • Onboard voltage level shifting for seamless 3.3V / 5V system compatibility.
  • STEMMA QT and Qwiic connectors enable solderless daisy-chaining with compatible development boards.
  • Dedicated READY output pin indicates conversion completion for efficient polling.
  • External SYNC input pin allows for hardware-triggered, synchronized sampling across multiple units.
  • Compact breakout design with mounting holes for secure installation in end applications.

Applications

  • Environmental UV index monitoring and solar irradiance studies.
  • UV curing process monitoring in industrial printing and coating systems.
  • Safety compliance testing for UVC germicidal lamp output and exposure limits.
  • Agricultural research monitoring UV light effects on plant growth.
  • Material degradation testing under controlled UV exposure conditions.

Technical Specifications

Sensor TypeAS7331 Spectral UV Sensor
UV ChannelsUVA, UVB, UVC (independent)
Spectral Range (UVA)320–400 nm
Spectral Range (UVB)280–320 nm
Spectral Range (UVC)200–280 nm
Measurement Range (UVA)Up to 349 mW/cm²
Measurement Range (UVB)Up to 386 mW/cm²
Measurement Range (UVC)Up to 169 mW/cm²
Sensitivity (Responsivity)As low as 2.38 nW/cm² per LSB
InterfaceI2C (Digital Output)
Default I2C Address0x74 (Configurable)
Output ResolutionUp to 24-bit internal
Operating Voltage3.3V / 5V compatible
ConnectivitySTEMMA QT / Qwiic connectors
Additional PinsREADY, SYNC
Multi-device SupportUp to 4 sensors on same I2C bus
Software SupportArduino & CircuitPython libraries
Dimensions (Board)25 x 17 x 10 mm
Weight3 g

Frequently Asked Questions

What is the default I2C address of the AS7331 breakout, and can it be changed?

The default I2C address is 0x74. The breakout includes address selection jumpers, allowing you to configure up to four unique addresses (0x74–0x77) to operate multiple sensors on the same I2C bus without conflicts.

Is this sensor compatible with both 3.3V and 5V microcontroller systems?

Yes, the breakout board includes an onboard voltage level shifter, making it fully compatible with both 3.3V and 5V logic levels. You can power it from either a 3.3V or 5V supply, and the I2C communication lines are automatically shifted to match.

How do the READY and SYNC pins function on this module?

The READY pin is an open-drain output that goes low when a conversion is complete, allowing efficient polling without constant I2C reads. The SYNC pin is an input that accepts an external trigger signal to synchronize the start of conversions across multiple AS7331 sensors for simultaneous sampling.

What libraries are available for programming this sensor with Arduino or Raspberry Pi?

Adafruit provides a comprehensive Arduino library (Adafruit_AS7331) and a CircuitPython library (adafruit_as7331) for easy integration. These libraries handle sensor initialization, configuration of gain/conversion settings, and reading calibrated UV data for all three bands.

Package Includes

  • 1 x Adafruit AS7331 UV / UVA / UVB / UVC Sensor Breakout Board
  • 1 x 6-pin Header (unassembled)

Additional Information

Weight 0.003 kg
Dimensions 1.7 × 2.5 × 1 cm