YugenFlow v2 is a compact, easy-to-use, low-power smart thermal sensor board that uses low-resolution thermal sensors to detect the presence of people and determine whether they are moving in a given direction. The sensor determines the direction along an axis, the physical meaning of which depends on how the sensor is mounted. YugenFlow does not require motion to detect presence, but can use it to determine orientation. The sensor can detect and "track" up to two people simultaneously from a distance of approximately 40 centimeters. It's also very fast.