The Problem Infrared thermometers are becoming more and more popular: The Fiber measuring is just quicker. But the measuring accuracy depends on the person who measures. A incorrect handling could result in a measuring difference from more then one degree Celsius. The inspiration and concept Everybody put headphones to the ears. This movement is familiar to us. It is a culturally learned behavior and it generated no discomfort. But a modern infrared fever thermometer is nothing that we use intuitively. The basic idea behind this concept was to use a familiar form. So that everyone knows how to handle it "Care" is a user- friendly infrared thermometer that shows how influential a learned behavior is for the design of a new product. To measure the fever, the thermometer is held at the ear and the measur sensor is simply inserted into the ear. To ensure that the measuring sensor is placed correctly in the ear the thermometer gives acoustic signals.