Jens Temperature Sensor Coaster

This coaster detects the temperature of a cup. You get a signal when it is ready to drink.

Temperature Sensor Coaster
I was drinking hot coffee. First I burned my mouth on it. Then I forgot about it and it cooled down to room temperature. With a sore mouth and cold coffee I realized that I had failed to drink a cup of coffee. Then I asked myself: Could I, without any knowledge about Arduino, make a device solving this problem for me?

Challenge accepted!

How about creating a coaster with a temperature sensor making it possible to set the “too hot” and the “too cold” temperatures and then a red, green and blue LED displaying in what range the temperature is. The device should have a buzzer giving a sound when the temperature reached the drinkable temperature.”