Automatic Monitor Color Temperature Adjustment

Adjust the color temperature of your computer monitor based on the temperature of ambient light!

by Tony DiCola

published March 28, 2014, last edited March 28, 2014

posted in Sensors/ Light

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Beginner

Project guide

Hardware

You'll need the following parts to build this project:

	Arduino Uno, Micro, or other Arduino which supports USB serial and I2C communication.
	Optionally an FTDI FT232H chip or cable, either 5 volt or 3.3 volt version will work. This cable can be used to communicate with the color sensor in place of the Arduino. Note that the code to talk to the chip only works with Linux or MacOS X--if you're on Windows stick with using an Arduino.
	Right angle header to solder on the color sensor for flush mounting to a monitor.
	Female to male extension cables for connecting to the color sensor.
	Velcro or other means to attach the sensor to the front of your monitor.
	RGB Color Sensor You can use the Flora RGB color sensor too, but the breakout board sensor will be easier to mount to a right angle header.

Assembly

The assembly of this project is very simple. Cut the right angle header to size and solder it to the color sensor. Connect the color sensor to the Arduino as follows:

Color sensor 5V to Arduino 5V
Color sensor GND to Arduino ground
Color sensor SDA to Arduino SDA (analog 4 on older Arduinos, check your your board pinout to be sure)
Color sensor SCL to Arduino SCL (analog 5 on older Arduinos, see above to check others)
Color sensor LED to Arduino ground to disable the built-in LED.

Above you can see a picture of the hardware connected to an Arduino Nano.

If you're using the FT232H cable instead of the Arduino, connect it to the sensor as follows:

If using the 5V cable: color sensor 5V to cable power (red)
If using the 3.3V cable: color sensor 3.3V to cable power (red)
Color sensor GND to cable ground wire (black)
Color sensor SDA to both the cable green and yellow wires to duplex the sent and received I2C data.
Color sensor SCL to cable clock wire (orange)
Color sensor LED to cable ground wire (black)

I found it was easiest to cut a few female to male extension cables up and solder them into 2-into-1 Y adapters to connect the SDA -> green and yellow, and GND & LED -> ground connections.

Above you can see a picture of the hardware connected to a 3.3 volt version of the FT232H cable.

If you have questions about using the FT232H cable, check out its data sheet here or this application note on using the cable to talk I2C.

Page last edited March 21, 2014