The goal of the one week course Sense your Heart was to get a grip on the workings of the human heart and a basic understanding of PPG and related systems like GSR and ECG and how they measure correctly thanks to high- and low pass filters. These principles were put to the test in a design brief in which we made a PPG sensor and developed a concept around it. The resulting marble maze uses the heart rate monitor to measure stress levels and become harder the more stressed the user is.