Contiki is an open source operating system for the Internet of Things. Contiki is used in a wide variety of systems such as city sound monitoring, street lights, networked electrical power meters, industrial monitoring, radiation monitoring, construction site monitoring, alarm systems, and remote house monitoring.
Contiki allows tiny, battery-operated low-power systems communicate with the Internet. Contiki provides powerful low-power Internet communication. Contiki supports fully standard IPv6 and IPv4, along with the recent low-power wireless standards: 6lowpan, RPL, CoAP. With Contiki’s ContikiMAC and sleepy routers, even wireless routers can be battery-operated.
Contiki is developed by a world-wide team of developers with contributions from Atmel, Cisco, ETH, Redwire LLC, SAP, SICS, and many others, led by Adam Dunkels of Thingsquare. The system is supported by the Contiki Community.
Source: Contiki Website