On 19th April 2004, the design of Ronja Twister has been released and this has given rise to a new model called Tetrapolis.
Ronja Tetrapolis is a device for optical communication with 10Mbps full duplex speed over 1.4km. The device terminates an optical path. To operate a complete link, two devices are necessary. This is a complete guide how to build one Ronja Tetrapolis device from scratch, based on common parts obtainable in retail shops worldwide.
This guide is aimed at any individual with some basic technical skills. It enables the reader to manufacture this device at low cost from common, non-specific parts readily available at common retail shops and using common household tools and several non-critical cheap electronic hobby tools that are easily available also in common retail stores. The device (Reasonable Optical Near Joint Access) allows fast, legal, unlimited, uncontrollable, and mostly confidential data communication free of any charge between two houses or flats that have direct optical visibility between them. The data communication is performed between two PC's, switches, routers etc. and may include routing IP packets, maybe extending the reach of Internet into one of the two households.
Aiming of the device is very easy and intuitive and in no phase between going shopping and using the device it is necessary to borrow any specialized equipment like oscilloscopes, cameras, telescopes, walkie-talkies or similar. The device has been designed from the beginning to be as easily built as possible.
This guide discusses first some general characteristics of Ronja Tetrapolis which should help you to decide if it is really suitable for your intended application. Then there is a section helping in decision of some important technical details, like lens diameter and holder type. A shopping list follows, building guide, testing guide, installation guide, aiming guide, and at last a maintenance and troubleshooting is discussed.