Purpose: Measures ambient light intensity, infrared (IR), and ultraviolet (UV) radiation levels.

Typical Use Cases: Smart lighting, wearables, environmental monitoring, sun exposure tracking.

Common Sensors:

• Si1145/Adafruit SI1145: Integrated sensor for visible, IR, and UV index.
• VEML6075: Dedicated UV sensor with UVA/UVB photodiodes.
• APDS-9301/9306: Ambient light and IR digital converter.

Interface: I²C (most common), SPI optional on some models.

Voltage Range: 2.5V – 5.5V (check datasheet).

Key Features:

• Separate channels for visible, IR, and UV light
• Digital output with programmable gain/integration time
• Low power consumption for battery operation
• Some include interrupt support for threshold detection

Design Tips:

1. Place sensor under clear lens or window; avoid tinted covers.
2. Shield from internal PCB IR sources (e.g., LEDs).
3. Use bypass capacitor (0.1µF) near power pins.
4. Calibrate against known light source if high accuracy needed.