{ I was informed about this by a friend over email <3 I basically paraphrase here what he told me. See also http://www.modulatedlight.org/. ~drummyfish }
Ronja (reasonable optical near joint access) is a free/open KISS device for wireless connection of two devices using light (i.e. optical communication) and the ethernet protocol; it can be made at home (for about $100), doesn't require any MCUs and as such can be considered a LRS/suckless alternative to traditional WiFi routers that are de-facto owned and controlled by corporations. It works full duplex up to the distance of 1400 meters with a speed of 10 Mbps, which is pretty amazing. One can also imagine Ronja as a kind of ethernet cable, just implemented with light instead of electricity. The design is released under GFDL. The project website is at http://ronja.twibright.com/.
There are many advantages in Ronja -- besides the mentioned KISS design and all its implications (freedom, repairability, cheap price, compatibility, ...), Ronja doesn't use radio so there are no bullshit issues with legal bands etc., it also works with just an ethernet card, offers a stable and constant transmission speed with very low latency, can be potentially harder to block with jammers and to spy on: besides visible light the transmission can also use infrared spectrum and narrow direction of transmission, as opposed to radiating to all directions like wi-fis, also the fast flickering of the LED is unnoticable by human or even normal cameras, therefore Ronja transmission is expensive to detect. Also note that some kind of protocol-level encryption can be used above Ronja, if one so desires. This makes it a nice communication tool for people under oppresive regimes like those in China or USA.
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