For wearable applications, such as fitness trackers and baby monitors, measuring skin temperature accurately can be challenging due to two major concerns: accuracy and speed.
Accuracy can be addressed by choosing a high-precision temperature sensor, as well as employing good PCB layout techniques.
A temperature sensor’s thermal response is how fast the device responds to a sudden change in temperature. The speed of the response is determined by the amount of thermal mass—a material’s ability to store heat energy—surrounding the sensor. By using good layout techniques, engineers can maintain a small thermal mass to improve the thermal response time.