Zigbee / Xbee

• Simple, small and cheap serial radios

• RS232 interface

• Analog and digital IO can be sampled and transmitted

• Can be run independently (without a computer or arduino).

• Series 1 modules are Point to Point or Broadcast

• Series 2 (aka 2.5) support Mesh Networking for greater range.

• Coordinator, Routers, and End device modules as determined by which firmware you flashed.