The SmartThings hub is a single plastic box which contains four different protocol managers. There is a Z wave controller, a Zigbee Coordinator, an ethernet connector which can take you out to the Internet through your regular Internet router , and a Bluetooth radio which is not currently turned on.
So there are literally dozens of different motion sensors that you could use with your SmartThings account. Different ones have different ranges. There is one which is manufactured by SmartThings, but you’re certainly not limited to it.
In terms of motion sensors, pretty much any motion sensor which is a certified zwave device or uses the zigbee home automation profile (ZHA 1.2) can be connected to SmartThings, although if the manufacturer has added some proprietary features they might not all be available.
Typical range for motion sensors intended for indoor residential use is normally 30 feet from the point of the sensor, but there is variation.
SmartThings’ commitment to open standards is one of the most attractive things about the system for many of its customers as it gives us a lot more choice in the devices we can connect.