Overview

The VCNL4010 is a fully integrated proximity and ambient light sensor (ALS) manufactured by Vishay Intertechnology. Packaged in a compact $3.95 \times 3.95\text{ mm}$ QFN package, it combines an internal $890\text{ nm}$ Infrared (IR) emitter LED, an IR proximity photodiode, an ambient light photodiode matching the human eye response, and a 16-bit low-noise Delta-Sigma ADC over an $I^2C$ bus (0x13).

Designed to detect object reflection and distance from $1\text{ mm}$ to $200\text{ mm}$, the VCNL4010 features programmable IR LED drive currents ($10\text{ mA}$ to $200\text{ mA}$) and automatic $50\text{ Hz} / 60\text{ Hz}$ ambient light flicker rejection. It is widely used in smartphone screen proximity lock circuits, robot obstacle detection, and smart touchless switches.

Quick reference

Pinout

Breakout module header & STEMMA QT / Qwiic connectors:

Specifications

Proximity & Ambient Light Registers

• Command Register (0x80): Enable proximity (0x08), enable ambient light (0x04), or start measurements.
• IR LED Current Register (0x83): Configures IR LED drive current ($0\dots 20 \times 10\text{ mA}$).
• Ambient Light Data (0x85–0x86): 16-bit ambient light count ($0\dots 65535$).
• Proximity Data (0x87–0x88): 16-bit proximity count (Higher counts indicate CLOSER object distance).

Wiring

Example (Adafruit_VCNL4010 Library)

#include <Wire.h>
#include "Adafruit_VCNL4010.h"

Adafruit_VCNL4010 vcnl;

void setup() {
  Serial.begin(115200);
  while (!Serial) delay(10);

  Serial.println("Adafruit VCNL4010 Proximity & ALS Test");

  if (!vcnl.begin()) {
    Serial.println("VCNL4010 not found! Check I2C wiring.");
    while (1);
  }

  // Set IR LED current to 200 mA for maximum proximity range
  vcnl.setLEDcurrent(20); // 20 * 10mA = 200mA

  Serial.println("VCNL4010 initialized.");
}

void loop() {
  uint16_t ambient = vcnl.readAmbient();
  uint16_t proximity = vcnl.readProximity();

  Serial.print("Ambient Light: "); Serial.print(ambient);
  Serial.print(" | Proximity Count: "); Serial.println(proximity);

  delay(200);
}

Common mistakes

• Interpreting proximity raw count as millimeters: Proximity output is an uncalibrated 16-bit reflection count, not direct distance in mm. Higher counts mean an object is CLOSER.
• Setting IR LED current too low: Running at $10\text{ mA}$ limits effective proximity sensing to $<20\text{ mm}$. Set setLEDcurrent(20) ($200\text{ mA}$) for maximum $200\text{ mm}$ sensing range.

Notes

• VCNL4010 vs APDS-9960 vs VL53L0X: VCNL4010 uses IR intensity reflection; APDS-9960 adds gesture recognition; VL53L0X uses Time-of-Flight (ToF) laser pulsing for millimeter-accurate absolute distance.