One of the very famous hardware device among the Hardware Hacker community  i.e. zigbee  is used to  connect wirelessly with another using the Zigbee communication protocols. From Wikipedia, Zigbee is: ZigBee is a specification for a suite of high level communication protocols using small, low-power digital radios based on the IEEE 802.15.4-2003standard for wireless home area networks (WHANs), such as wireless light switches with lamps, electrical meters [...]