For low-cost home automation, pretty much all of the “motion” sensors are actually PIR (passive infrared) Sensors which measure very small changes in heat moving across the detection field. These are inexpensive and work well indoors.
The next level up you will find built into some cameras actually looks at visual field changes, but those devices tend to be a lot more expensive and you don’t see them in standalone sensors for home use. But if you’re already buying a Camera or a video doorbell, there are some brands that will allow you to trigger smartthings events off of the motion sensor detection in the camera.