How to go about making a circuit that detects colour change?

Thread Starter


Joined Nov 16, 2015
Hi guys very new to electronics. I want to able to indicate a change in color digitally. For example a red that turns into a darker red an LED would light up and indicate the colour change. What sort of sensor can do this and where do I start.

Thanks a bunch guys!


Joined Sep 9, 2010
An old-school solution would simply be a light detector with a filter in front of it, with the appropriate absorption spectrum to discriminate the two colors. I think there is a medical tool like this, that distinguishes arterial blood from venous blood, or something like that.