Our smartphones, as well as other connected devices and consumer apps, collect and store data that may contain useful insights about our health, fitness, and other activities. However, this data is typically challenging to collect, access, and analyze. In this post, Uri Merhav describes how he used the Moonsense recorder app to gather acceleration, gyroscope, and geographic data from his iPhone. He reviews how he implemented some relatively simple logic and applied low pass filters to develop a squat counting app.