Wearable devices are becoming more common each year. These devices come in many shapes, and carry out numerous functions. The website MobileHealthNews.com reported in 2014 that 1 in 5 Americans own a wearable device and 1 in 10 wear it on a daily basis. Statista.com reported in January of 2016 that global wearable market is expected to exceed $19 billion dollars in 2018. At the heart of these wearable devices are tiny sensors and energy harvesters. This lesson focuses on the capabilities of, and applications for, these tiny sensors.