June Birth Magoncia

user Electronics Engineer

city Innovuze Solutions, Inc.

  • ISL29125 Digital RGB Color Light Sensor

  • Created: Feb 10, 2016

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The ISL29125 is a highly sensitive digital RGB color light sensor but with low operating voltage and low current supply. It operates in a voltage range of 2.25V to 3.63V, consumes 0.5uA current when powered down and 85uA current utmost when it is active. The design of ISL29125 includes rejection of IR in light sources making it possible to operate normally when exposed to sunlight or used in dark rooms. The device offers two optical sensitivity ranges, Range 0 ranges from 5.7mlux to 375lux and Range 1 ranges from 0.152lux to 10000lux. This range selectivity permits the user to optimize the device capabilities for a specific application.

This circuit detects the color of the object placed on the top of the color sensor and displays the name of the color as well as the RGB color values. It is composed of ISL29125 color sensor, ATmega328P microcontroller, I2C OLED graphic display, 3.3V regulator, 3.3V to 5V bidirectional logic converters, and some passive components. The operation of the circuit starts at the color sensor ISL29125 sensing the red, green, and blue color light intensity and convert it to current. After the process of light to current conversion, the current will be converted into a digital count by an internal analog-to-digital converter of the color sensor. This digital information will be transmitted to the microcontroller over the I2C bus and will be analyzed to determine the RGB values and color name. After determining the RGB values and the name of the color, the ATmega328P microcontroller will transmit the result to the OLED graphic display over the I2C bus again. The OLED graphic display will show the red, green, and blue decimal (hex value converted into decimal) values of the color and the name of the object’s color.

This circuit design is useful in determining the color of an object especially if the user is not familiar with all the color names or if the user is colorblind. The user can now easily identify the color of an object by using this circuit. Though the ISL29125 runs typically with a 3.3V power supply, the whole circuit can be supplied with a 5V source since the circuit uses a 3.3V regulator for the ISL29125 device. The ISL29125 device also is not just limited to this kind of application. It can be also used for dynamic display color balancing, printer color enhancement, industrial/commercial LED lighting color management, ambient light color detection/correction, OLED display aging compensation, etc.