Li-Fi

Li-Fi is WiFi with light instead of radio waves. This method of wireless communication is more secure than WiFi because light waves won't pass through walls. The light doesn't have to be infrared or ultraviolet, so it can be used in the dark. It also has potential for long range applications by using lasers. This tech is still developing so its not useful for home use quite yet, but its not that far away. What are lain's thoughts on this upcoming tech? And are there any other wireless communication methods you think are better than wifi? https://en.wikipedia.org/wiki/LIFI There is also an open source implementation of LiFi http://www.openvlc.org/

Sure it is more secure but it can't pass through walls not very helpful when you want to maintain a big network with a lot of mobile devices It looks neat but I would prefer plain old wifi if you are concerned about security then either use ethernet or use the latest revision of wifi with WPA2

it's going to be a lot more secure and cause less congested wifi networks in high density areas and buildings

But I won't be able to fap under the covers during long distance sexytiems anymore.

>>7193 It's hard to decide where to even begin with posts like this one.

-wifi is already on the EM spectrum, just not in the visible portion of it -it would be unusable in presence of any other light source due to heavy interference -why would you want your signal to not pass through walls? Why not just use a cable if you're in the same room as your AP?

>>7199 smartphones, mostly

>>7199 >it would be unusable in presence of any other light source due to heavy interference If I stood across from you in a well lit cafeteria with a flashlight and tapped morse code at you, would you be able to receive it? (assuming you could read morse code of course).

>>7209 not if it was a low-powered flashlight.

>>7210 Look, in the 1800s they learned how to send multiple telegraphs on a single wire by using multiple frequencies. Think of it something like that. Light sensing technology in 2018 might be more sensitive than your eyes or mine. Besides, it's a given that this is for extremely short range, as in, in the same room, since the fact that it can't penetrate walls is actually touted as a selling point.

The biggest problem I see with this is that your device will need some exposure to ambient light. The receiver has to involve some kind of ambient light sensor. This is probably fine for laptops and desktop computers, but the average joe will be pretty pissed if he can't put his phone in his pocket without breaking a connection. It seems like interference would be a big problem. Does white (or close to white) light from common sources (the sun, room lighting, LEDs, etc) fall on a narrow, predictable spectrum? Can you build a Li-Fi router that produces a receivable signal in any well-lit room, as long as there are walls to reflect off of? Are there certain wavelengths that natural and artificial light sources usually don't touch, that would be open to use for Li-Fi? My guess is that there's much more noise in the visible light spectrum than in the radio spectrum. Correct me if I'm wrong. I know that there are many advanced techniques in comms engineering that let devices pull signals out of pretty intense noise, maybe those can be applied to communication in visible light. And in a controlled environment (i.e., fiber), this makes a lot of sense. I can see certain types of businesses and stores using this tech. But I don't think it will replace radio, the design requirements for radio are just too convenient.

>>7211 But it's only possible to communicate in specific channels like this when you can overcome or remove interference. With radio, there are bands that are generally interference-free, or at least quiet enough that we can overcome it with a strong transmission. With something like fiber, the signal is sent through a channel that physically removes all interference. I'm wondering how big of a problem ambient light will be for Li-Fi compared to noise for radio.

I think the same way your phone has connection in a city. With thousands of others all using basically the same radios is by using different frequencys. Light would be used the same way. This isnt really a problem because of the range, but you could always tune the transmitter/reciever to more specific parts of the spectrum. E.g. using 1.421 instead of 1.4 [s]not really the frequencys, just example numbers.[/s]

>>7213 I think this lain got it: >>7222 If your new xmas lights or lava lamp are messing with your li-fi suddenly, there could be channels to choose from.

>>7227 >>7222 So it just depends on how precise we can make the receivers & transmitters. I wonder if there's some band where there's less interference from ambient light, that would let us cram in loads of channels. My guess would be that ambient light is more powerful towards IR than UV. It would be nice to see a chart like this one, but that plots the magnitude light coming from typical EM sources or something instead of atmospheric capacity.

>>7230 s/capacity/opacity/ I need to wake up.

>>7183 A big problem is that you'd basically need line-of-sight for this work. What if they routed the Li-Fi through a series of tubes that could take the light around corners, through walls, and even vast distances underground?

>>7236 It doesn't need to be line of sight, light can be reflected off of walls or other things. But it does seem pretty limited to indoor applications.

repeaters would be cheap as they would basically be mirrors

>>7242 >repeaters would be cheap as they would basically be mirrors Repeaters are supposed to retransmit in order to boost the signal so that it can travel further. A mirror kind of does the opposite of that.

*passes through your laser* heh nothing personnel........ kid

>>7248 Great, now we have to make the lasers dangerous so people don't mess with them