Ramps 1.4 leds...

Is it possible to program leds to change color based of the temperature of the extruder or heated bed.

Like the makerbot replacator 2

When its cold its blue
heats up starts to turn red
when its hot and starts to print back to white. and after a while they shut off. something like this

anyone make this already.

All you need is a tri color led

eg [www.sparkfun.com]

You connect each color to a IO pin. (doesn’t needs to be a PWM pin if your just wanting on and off)

Looks like this is mostly already in marlin,

See in configuration.h

// Support for an RGB LED using 3 separate pins with optional PWM
//#define RGB_LED
#if ENABLED(RGB_LED)
#define RGB_LED_R_PIN 34
#define RGB_LED_G_PIN 43
#define RGB_LED_B_PIN 35
#endif

then M150 - Set Status LED Color as R U B. Values 0-255.

But there is no code to change color related to temp. Someone would have to add this.