What is it?

Small (0.25 in x 0.7 in) breakout board to be mounted directly onto your favorite microcontroller or on the breadboard. Measure red, green, and blue as well as white (infer IR irradiance). Convert the raw counts into power density (microWatts per square centimeter) with given sensitivities for each spectral range, use the green channel as an ambient light sensor in lux since the green response closely matches that of the human eye. Lastly, determine the correlated color temperature of a light source as part of general color measurement and feedback.

The VEML6040 is the latest generation of rgbw color sensors from Vishay with improved I2C interface and an exquisite range of absolute sensitivity configurable by the user. It is small, inexpensive and makes the perfect addition to your next environmental sensor suite or tricorder design!

From the data sheet:

"VEML6040 color sensor senses red, green, blue, and white light and incorporates photodiodes, amplifiers, and analog / digital circuits into a single chip using CMOS process. With the color sensor applied, the brightness, and color temperature of backlight can be adjusted base on ambient light source that makes panel looks more comfortable for end user’s eyes. VEML6040’s adoption of FiltronTM technology achieves the closest ambient light spectral sensitivity to real human eye responses.

VEML6040 provides excellent temperature compensation capability for keeping the output stable under changing temperature. VEML6040’s function are easily operated via the simple command format of I2C (SMBus compatible) interface protocol. VEML6040’s operating voltage ranges from 2.5 V to 3.6 V. VEML6040 is packaged in a lead (Pb)-free 4 pin OPLGA package which offers the best market-proven reliability."

I have added an option for the VEML6075 UVA/B sensor which has the same package footprint and board layout but is labeled as a VEML6075 and, of course, detects UV light in the A and B bands.

Why did you make it?

I love sensors and can't help but try out the latest and greatest. I also love appallingly small and the combination of new, better, and small is irresistible for me. I designed a very small breakout so I could test the VEML6040 sensor and learn how to use it well. I plan to integrate it into all of my projects that need ambient light sensing or color measurement.

What makes it special?

The sensor is first rate from a company that knows how to make products small and rugged and easy to use. The improved I2C protocol is much easier (more conventional) to use than that on the VEML6070 UV sensor and I was able to get the sensor up and running within an hour. I have written a sketch that parametrizes the registers, reads all the data and converts it to all of the interesting absolute measurements available.

Order the pcb from OSH Park and assemble some of your own, or buy the assembled and tested breakout board from me and see how easy absolute color measurement can be!