7Semi OPT3004 Digital Ambient Light Sensor Breakout with I2C STEMMA QT / Qwiic

Overview

The module is based on the Texas Instruments OPT3004, a high-precision digital ambient light sensor (ALS) designed to measure visible light intensity (lux).

• Acts as a single-chip lux meter

• Spectral response closely matches the human eye

• Designed for accurate real-world light measurement

Unlike simple photoresistors, it provides calibrated digital lux output.

Working Principle

Photodiode-Based Light Detection

• Uses an integrated photodiode

• Converts incoming light electrical signal

Optical Filtering

• Includes precision optical filter

• Matches human eye response curve (photopic response)

This ensures:

• Accurate readings under sunlight

• Minimal error from IR sources

Automatic Gain Control

• Built-in auto-ranging system

• Adjusts sensitivity automatically

Allows measurement across very wide light levels without manual tuning.

Measurement Characteristics

• Light range: 0.01 lux to 83,000 lux

• Resolution: up to 0.01 lux

• Dynamic range: 23-bit effective

Covers:

• Very low light (dark rooms)

• Bright daylight conditions

Accuracy & Response

• High accuracy with human-eye matched spectral response

• Typical accuracy: ~Strong IR rejection ensures consistent readings across light sources

Electrical Characteristics

• Supply voltage: 1.6V to 3.6V

• Operating current: ~1.8 A (typical)

• Very low power suitable for battery systems

Communication Interface

• Interface: I2C (two-wire digital communication)

• Typical speed: up to 1 MHz

Data Output

• Direct lux value output

• No external calibration required

Internal Features

Automatic Full-Scale Range

• Adjusts gain automatically

• Prevents saturation in bright light

Programmable Interrupt

• Generates interrupt when:

  • Light exceeds threshold

  ems

  Digital Signal Processing

  • Converts raw photodiode signal linear lux output

  • Compensates environmental variations

   

  STEMMA QT / Qwiic Interface

  Plug-and-Play I2C Connectivity

  • Uses 4-pin JST connector

  • Pins:

    • VCC

    • GND

    • SDA

    • SCL

     

   

  Benefits:

  • No soldering required

  • Easy daisy-chaining of multiple sensors

   

  Physical Characteristics

  • Sensor IC size: ~2.0 2.0 0.65 mm

  • Breakout board size: ~27 20 mm

  • Compact and lightweight

   

  Environmental Characteristics

  • Operating temperature: 40C to +85>

  Operating Behavior

  Wide Range Adaptability

  • Automatically adjusts between:

    • Dark environments

    • Bright sunlight

  Light Source Independence

  • Accurate under:

    • LED

    • Fluorescent

    • Sunlight

  Due to strong IR rejection and spectral matching

  Limitations

  • Measures visible light only (lux)

  • Cannot:

    • Identify light color

    • Measure UV or IR levels

  • Accuracy depends on:

    • Sensor placement

    • Obstruction/shadowing

  Breakout Board Role (7Semi)

  The breakout board:

  • Provides:

    • Voltage compatibility (3.3V / 5V systems)

    • I2C access via header +ifies integration with embedded systems

    Summary

    The 7Semi OPT3004 breakout is a high-accuracy ambient light sensing module that:

    • Measures visible light intensity in lux

    • Uses photodiode + optical filtering + digital processing

    • Offers 23-bit dynamic range with auto gain

    • Provides low-power digital I2C output

    • Ensures accurate human-eye-like light measurement