Adafruit VCNL4040 Proximity and Lux Sensor - STEMMA QT/Qwiic

The breakout board is designed to operate from a 3.3V to 5V DC power supply. It includes onboard circuitry to safely level-shift the I2C signals, making it fully compatible with both 3.3V logic microcontrollers (like Raspberry Pi or ESP32) and 5V logic boards (like most Arduinos). Simply connect VIN to your system's 3.3V or 5V rail.

Connection is simplified via the onboard STEMMA QT (and Qwiic compatible) 4-pin JST SH connector. Use a matching cable to connect the sensor's I2C bus (SDA, SCL), power (3.3V/5V), and ground (GND) to your host board. For traditional wiring, the breakout pins are also available to solder headers or wires directly.

Yes, both sensors are highly configurable via I2C commands. For proximity, you can adjust the IR LED's pulse current and duty cycle to change detection range and power use. For ambient light, you can select from four integration times (80ms to 640ms); longer times provide higher resolution and sensitivity in low-light conditions.

Integration time determines how long the light sensor collects photons per measurement. An 80ms time gives a full-scale range of ~6553 lux, ideal for bright environments. A 640ms time increases sensitivity, reducing the full-scale range to ~819 lux but providing 8x finer resolution, making it better for precise measurements in dim light.

The sensor itself can measure light levels up to 6553 lux, which covers typical outdoor conditions. However, the breakout board is not weather-sealed (no IP rating). For outdoor deployment, the board must be housed in a protective enclosure that shields it from direct moisture, condensation, and UV exposure while allowing light to reach the sensor window.