The VEML6040 is a compact digital color sensor developed by Vishay. It measures red, green, blue, and white (RGBW) light intensity using photodiodes and provides digital output through the I²C interface.

It can be used to detect ambient light, estimate correlated color temperature, and read raw RGBW light values, making it useful for lighting control, color detection, display brightness adjustment, and environmental sensing projects.

Specifications
 

Library Installation
 

To use this sensor with Arduino, install a compatible VEML6040 library using the Arduino Library Manager.

1. Open the Arduino IDE.
2. Go to Sketch → Include Library → Manage Libraries...
3. Search for VEML6040.
4. Install a compatible library, such as VEML6040 by thewknd.

Example
 

#include <Wire.h>
#include "veml6040.h"

VEML6040 RGBWSensor;

void setup() {
  Serial.begin(9600);

  Wire.begin(2, 0);

  if (!RGBWSensor.begin()) {
    Serial.println("ERROR: couldn't detect the sensor");
    while (1) {}
  }

  RGBWSensor.setConfiguration(
    VEML6040_IT_320MS +
    VEML6040_AF_AUTO +
    VEML6040_SD_ENABLE
  );

  delay(1500);

  Serial.println("Vishay VEML6040 RGBW color sensor");
  Serial.println("CCT: Correlated Color Temperature in Kelvin");
  Serial.println("AL: Ambient Light in lux");

  delay(1500);
}

void loop() {
  Serial.print("RED: ");
  Serial.print(RGBWSensor.getRed());

  Serial.print(" GREEN: ");
  Serial.print(RGBWSensor.getGreen());

  Serial.print(" BLUE: ");
  Serial.print(RGBWSensor.getBlue());

  Serial.print(" WHITE: ");
  Serial.print(RGBWSensor.getWhite());

  Serial.print(" CCT: ");
  Serial.print(RGBWSensor.getCCT());

  Serial.print(" AL: ");
  Serial.println(RGBWSensor.getAmbientLight());

  delay(400);
}

The code initializes the VEML6040 sensor through the I2C bus and configures it with an integration time of 320 ms. In the main loop, the sensor reads the red, green, blue, and white channels, as well as the estimated correlated color temperature and ambient light level.

Output

The VEML6040 provides raw RGBW values and calculated light information. These values are useful for color sensing, light monitoring, and automatic brightness control projects.

Note: The RGBW raw values can vary depending on the configured integration time and gain. A longer integration time, such as 320 ms, increases sensitivity and may produce higher readings in low-light conditions.