DIY Color Temperature Meter
by viilaamo.com
Introduction
Here is how you can make a cheap color temperature meter on your own. Basic knowledge about electronics and Arduino programming is required; rather than just posting the source code - we also explain how it works.
In this example we use components that cost less than 40 euros just to demonstrate how it can be done.
Most expensive component is the Arduino board (22 euros) and the plastic housing (10 euros), the rest of the components cost total about 6 euros.