" Old but fascinating open hardware: 10MBit 1400m airlink w/ LEDs. -- Matt @matjahu
Ronja is a free technology project for reliable optical data links with a current range of 1.4km and a communication speed of 10Mbps full duplex.
Applications of this wireless networking device include backbone of free, public, and community networks, individual and corporate Internet connectivity, and also home and building security. High reliability and availability linking is possible in combination with WiFi devices. The Twibright Ronja datalink can network neighbouring houses with cross-street ethernet access, solve the last mile problem for ISP’s, or provide a link layer for fast neighbourhood mesh networks.
For more information on Ronja, see our about page.
September 2008 — Chris Long VK3AML from Australia (167 km amateur world record in 2-way voice optical communication on Mount Wellington, Tasmania) and Clint Turner KA7OE1 (273 km world record in Salt Flats, Utah) have published a website dedicated to Modulated Light Communications.
The website deals with history of various world records, has a lot of bibliography and discussion of technical details and contains audio recordings of the contacts.
August 2, 2007 — The Ronja 10M Receiver, 10M Metropolis Transmitter and Inferno Receiver modules have been mechanically upgraded to use mounting brackets instead of the former bolts or cylinders with inner thread. The mounting brackets are made from tin plated steel sheet, solve several problems at once and are easily made.
August 6, 2006 — Twister2 has been released. It's now a part of Ronja Tetrapolis and Ronja Inferno. It is smaller, based on SMD components, and saves 1.4W of power. The electronic parts cost 30% more, but is much faster to build, because the mechanical design is greatly simplified. Twister2 was designed because someone complained about TV interference. Twister2 radiates 8x less residual energy than Twister.