WEBVTT - Shedding Light on Li-Fi 0:00:00.160 --> 0:00:07.160 Brought to you by Toyota. Let's go places. Welcome to 0:00:07.360 --> 0:00:15.720 Forward Thinking. Hey guys, it's Forward Thinking. I'm Jonathan Strickland, Obama, 0:00:15.760 --> 0:00:19.400 and we are still back. If you listen to the 0:00:19.440 --> 0:00:22.280 previous episode Water on Mars, you know that we were 0:00:22.320 --> 0:00:24.799 on hiatus for a while. We are now back and 0:00:24.920 --> 0:00:28.320 this is the second of two episodes we recorded before 0:00:28.400 --> 0:00:31.600 we were officially on hiatus, but we back in October, 0:00:33.240 --> 0:00:35.280 so we're gonna tell you the future of the past. 0:00:36.040 --> 0:00:38.080 Um yeah, this is this is something that we recorded 0:00:38.080 --> 0:00:41.920 back in October two fifteen. It's all about LiFi and 0:00:42.120 --> 0:00:44.760 uh so some of the references maybe a tad dated 0:00:45.000 --> 0:00:48.159 because we were recording a few months ago, but we 0:00:48.240 --> 0:00:50.239 wanted to release it because we were really proud of it. 0:00:50.280 --> 0:00:52.160 I thought it was a good episode, and we've got 0:00:52.200 --> 0:00:55.080 lots of new episodes coming up in the next year, 0:00:55.200 --> 0:00:57.960 so we wanted to get back onto on track, get 0:00:58.000 --> 0:01:01.639 things going. And I hope you enjoy this now classic 0:01:01.760 --> 0:01:08.160 new episode of Forward Thinking. Hey there, and welcome to 0:01:08.280 --> 0:01:11.399 Forward Thinking, the podcast that looks at the future and 0:01:11.440 --> 0:01:15.160 says there's a light over at the Frankenstein Place. I'm 0:01:15.280 --> 0:01:20.200 Jonathan Strickland and I'm Joe McCormick. Hey, so guys, you know, 0:01:20.640 --> 0:01:24.240 we talked about something, uh a year ago or so. 0:01:24.319 --> 0:01:28.399 We're recording this in October two thousand and fifteen, but 0:01:28.680 --> 0:01:33.520 about a year ago September, we talked about a problem 0:01:33.560 --> 0:01:38.040 that's happening, and it's happening across the developed world places 0:01:38.080 --> 0:01:42.160 where the Internet has reached real penetration. And that problem 0:01:42.280 --> 0:01:45.119 is that a lot of the devices we use rely 0:01:45.400 --> 0:01:50.040 on radio signals to communicate with the infrastructure that connects 0:01:50.080 --> 0:01:55.320 to the Internet backbone. The spectrum crunch exactly, the spectrum crunch. 0:01:55.760 --> 0:01:58.200 That's a real issue. And the issue is not something 0:01:58.240 --> 0:02:00.480 where like you have an a limit that amount of 0:02:00.560 --> 0:02:03.240 radio in the entire world and it's all gonna go away. 0:02:03.320 --> 0:02:06.760 It's very much a a kind of a congestion. Think 0:02:06.760 --> 0:02:10.040 of it like a traffic jam in a particular region. Yeah. 0:02:10.080 --> 0:02:12.200 For the same reason that they ask you to put 0:02:12.240 --> 0:02:15.480 your phone on airplane mode when you're in an airplane, 0:02:15.960 --> 0:02:19.360 is this thing that we're talking about, because signal interference 0:02:19.440 --> 0:02:22.880 can become a very serious issue in that case. Well, 0:02:22.919 --> 0:02:24.919 not only just signal interference, but if you've got too 0:02:24.919 --> 0:02:27.480 many Like have you ever been in let's say a 0:02:28.040 --> 0:02:30.320 really crowded coffee shop and you want to connect to 0:02:30.320 --> 0:02:33.239 the WiFi there, but you occasionally find that you're being 0:02:33.280 --> 0:02:36.200 bumped off the WiFi or things are really slowing down 0:02:36.200 --> 0:02:40.240 and clogging up. Often it's because whatever WiFi router the 0:02:40.440 --> 0:02:43.480 coffee shop is using has a lower capacity than what 0:02:43.639 --> 0:02:46.840 is being demanded of it. So, in other words, there 0:02:46.919 --> 0:02:50.200 are the devices we use have a limited ability to 0:02:50.320 --> 0:02:53.880 deal with the demand that we are placing upon them, 0:02:53.919 --> 0:02:56.280 and it's getting worse by the day because not only 0:02:56.320 --> 0:02:59.679 are we getting more smartphones and tablets and smart watches 0:02:59.720 --> 0:03:02.160 and all this other stuff that's using those radio waves, 0:03:02.400 --> 0:03:05.880 were also entering the era of the Internet of Things, 0:03:05.960 --> 0:03:08.960 which is requiring even more stuff to connect to the 0:03:09.000 --> 0:03:13.239 Your fridge in your car, tires and your cube, connect 0:03:13.280 --> 0:03:17.840 to the internet, your cuff links, your dog's color, your hatchet. Yes, 0:03:18.360 --> 0:03:21.960 our mystical acts is um not WiFi enabled, but we're 0:03:21.960 --> 0:03:26.760 getting an upgrade, sobe is on the internet. Joe failed 0:03:26.800 --> 0:03:29.840 to solve me again, that would essentially it would just 0:03:29.880 --> 0:03:31.919 be a message like that for me all the time. 0:03:32.360 --> 0:03:37.800 Jonathan has has low spatial awareness. H so uh. The 0:03:37.880 --> 0:03:39.600 interesting thing here is that this problem is not going 0:03:39.640 --> 0:03:41.520 to go away. It's not gonna it's not gonna get 0:03:41.560 --> 0:03:44.000 any easier. In fact, there are places like here in 0:03:44.000 --> 0:03:49.920 the United States that have recently declared broadband access as 0:03:49.960 --> 0:03:53.120 being a necessity not a luxury. There was a White 0:03:53.120 --> 0:03:57.800 House report that came out earlier in that's specifically called 0:03:57.840 --> 0:04:02.920 out broadband access as a necessity, and they defined broadband 0:04:02.920 --> 0:04:05.160 as I think twenty five megabits per second are faster, 0:04:05.960 --> 0:04:09.160 mean saying like electricity, right, yeah, yeah, Well because because 0:04:09.200 --> 0:04:14.200 knowledge and interconnectivity is critical in this our modern world. Yes, 0:04:14.280 --> 0:04:17.359 we we rely on it for communication, we rely on 0:04:17.440 --> 0:04:23.080 it for commerce. So we have this this problem, and 0:04:23.160 --> 0:04:28.320 we have this, uh more, this increasing urgency to find 0:04:28.320 --> 0:04:30.720 a way of dealing with it. Um And there are 0:04:30.720 --> 0:04:34.560 other issues with WiFi. Besides the fact that they you 0:04:34.640 --> 0:04:38.960 can have a capacity crunch in any given time and place, 0:04:39.000 --> 0:04:42.520 depending upon demand. Another is that they're not always that 0:04:42.720 --> 0:04:46.320 efficient to use these radio waves. In fact, that's all 0:04:46.360 --> 0:04:50.440 they do, and so you're dedicating them to this one purpose. 0:04:50.920 --> 0:04:55.520 And I think the um the percentage I saw was 0:04:55.560 --> 0:04:58.039 that they are essentially five percent efficient in the amount 0:04:58.040 --> 0:04:59.919 of energy you're using them and the amount of actual 0:05:00.040 --> 0:05:03.880 work they're doing. Yeah, energy you're pouring into these things 0:05:04.600 --> 0:05:09.760 is just being bled away. Also, like you were saying, Lauren, 0:05:09.920 --> 0:05:12.480 you've got the problem with interference. You know. That's why 0:05:12.600 --> 0:05:18.080 you aren't allowed to use devices in on airplanes unless 0:05:18.120 --> 0:05:21.599 you've switched it to WiFi. You can't use the cellular data. Um, 0:05:21.640 --> 0:05:24.600 you can't use them in places like hospitals where it 0:05:24.680 --> 0:05:28.680 might interfere with medical equipment. That's another issue. I've got 0:05:28.680 --> 0:05:32.040 a complaint. When I wrap my computer up in aluminum foil, 0:05:32.120 --> 0:05:34.559 it can't get a WiFi signal, right, But they also 0:05:34.680 --> 0:05:38.839 can't I can't see what you're doing anymore, right, So 0:05:39.320 --> 0:05:41.320 that is the important part. That's we call it our 0:05:41.640 --> 0:05:44.720 essay protection case. And you can't see what you're doing 0:05:44.760 --> 0:05:49.080 anymore either, so your fragile sanity. He's trying to come 0:05:49.160 --> 0:05:52.800 up with some transparent aluminum foil. I've got a movie 0:05:52.880 --> 0:05:57.440 for you to watch. Uh So another issue, and I 0:05:57.440 --> 0:05:59.680 didn't even put this in our notes, but another one 0:06:00.279 --> 0:06:03.200 needs to be addressed is the notion of security. I mean, 0:06:03.240 --> 0:06:07.560 obviously there's the you've always heard. I'm sure you guys 0:06:07.600 --> 0:06:10.880 out there have heard that things like like open WiFi 0:06:10.960 --> 0:06:15.080 networks are risky because you never know who else is 0:06:15.120 --> 0:06:18.520 on that network and who might be intercepting your data? Right, Jonathan, 0:06:18.560 --> 0:06:21.080 Earlier you were like, you go to a coffee shop 0:06:21.120 --> 0:06:24.800 and use their WiFi. I'm like, no, you don't. Well, 0:06:25.520 --> 0:06:27.560 it depends on the coffee shop too, right, I mean 0:06:27.560 --> 0:06:30.360 it depends on It depends on multiple things, like is 0:06:30.400 --> 0:06:33.000 the is the WiFi protected in the coffee shop. Even 0:06:33.040 --> 0:06:35.760 if it is, there's still the chance it's unsecured. But 0:06:35.880 --> 0:06:39.320 if it's secured, the password is coffee, right, or or 0:06:39.480 --> 0:06:42.040 one to three coffee or something along those lines. But 0:06:42.279 --> 0:06:44.839 you know, even with all those things, Uh, if you're 0:06:45.880 --> 0:06:48.440 not doing your banking or whatever, maybe you're not too 0:06:48.480 --> 0:06:54.719 concerned about it. But one potential solution to all of 0:06:54.720 --> 0:06:59.360 these problems is to replace the radio part of this communication, 0:06:59.480 --> 0:07:05.000 the the communication between devices and the infrastructure that connects 0:07:05.000 --> 0:07:07.919 to the Internet backbone, with something besides radio. So a 0:07:08.040 --> 0:07:11.240 guy standing up on a table in the room holding 0:07:11.320 --> 0:07:15.240 flags up, uh, well, similar in that the communication would 0:07:15.280 --> 0:07:18.760 depend upon light. And if we wanted to use flags, 0:07:18.800 --> 0:07:20.920 then obviously light as necessary because I don't know if 0:07:20.960 --> 0:07:25.160 you've tried to communicate via semaphore and pitch darkness with 0:07:25.360 --> 0:07:30.200 unlit flags not terribly productive. What if the flags are 0:07:30.200 --> 0:07:32.600 glow in the dark, that's different then you've got but 0:07:32.640 --> 0:07:35.440 there's some blurring issues too. I guess the flags probably 0:07:35.440 --> 0:07:37.920 would mean it would take a long time to download 0:07:37.960 --> 0:07:41.080 a file. So what's something that we're talking about like 0:07:41.280 --> 0:07:47.400 the bond modem days, So what's something that would be 0:07:47.440 --> 0:07:49.920 a little bit faster than a guy holding up flag signals? 0:07:50.000 --> 0:07:53.920 Actual light, I mean actually using light in place of 0:07:54.080 --> 0:07:58.160 radio waves, like pulses of light kind of yeah, like 0:07:58.160 --> 0:08:03.080 like changing the amplitude of light, so the intensity of light, uh, 0:08:03.120 --> 0:08:07.080 in order to communicate, which is not the unusual. Yeah, yeah, well, 0:08:07.120 --> 0:08:08.720 I mean we we've been doing it for a very 0:08:08.840 --> 0:08:11.160 very long time. But we're talking about something that would 0:08:11.160 --> 0:08:16.880 have to move a little bit faster than for example, uh, beacons, right, yes, 0:08:16.920 --> 0:08:20.240 like the old days where you know the you're you, 0:08:20.240 --> 0:08:24.520 you are a messenger and you see that there are 0:08:25.000 --> 0:08:27.880 invaders coming in at the northern border of the country 0:08:27.920 --> 0:08:29.800 you live in, so you light the beacon to alert 0:08:29.840 --> 0:08:31.760 everybody else. It's that's seen in the Lord of the 0:08:31.800 --> 0:08:34.280 Rings where they like the beacon to U to call 0:08:34.400 --> 0:08:38.560 the who are the writers of rowan? Yes, don't test me, buddy, 0:08:39.400 --> 0:08:41.720 I was actually just playing the Shadows of mortor game, 0:08:41.800 --> 0:08:44.200 and the Orcs use beacons in that came a boy, 0:08:44.200 --> 0:08:48.160 are they irritating anyway? Uh? Greeks and Romans were using 0:08:48.240 --> 0:08:51.640 mirrored plates to send messages using light. They would flash 0:08:51.720 --> 0:08:55.080 light in in a series of flashes to indicate one 0:08:55.120 --> 0:08:58.920 thing or another. Uh. There's the famous story in American 0:08:59.040 --> 0:09:02.439 history during the Revolutionary War in which the Old North 0:09:02.559 --> 0:09:06.040 Church in Boston was used to alert messengers to the 0:09:06.240 --> 0:09:09.640 troop movements of British troops. The whole one if by 0:09:09.720 --> 0:09:13.679 land too, if by sea, referred to in Longfellow's poem 0:09:13.720 --> 0:09:17.479 Paul Revere's Ride, which may or may not be apocryphal. 0:09:17.520 --> 0:09:23.000 There's some arguments historically speaking about what exactly happened. Essentially, 0:09:23.040 --> 0:09:25.599 people say that yes, lights were used. Whether or not 0:09:25.760 --> 0:09:27.600 was the Old North Church is still the matter of 0:09:27.640 --> 0:09:30.560 some debate. But at any rate, we've been using lights 0:09:30.559 --> 0:09:33.120 like this for ages. Yeah, and that that is definitely 0:09:33.400 --> 0:09:37.320 encoding data in light. But right, it's pretty limited that 0:09:37.400 --> 0:09:40.839 The fancy word which Jonathan just mentioned earlier actually is semaphore, 0:09:41.400 --> 0:09:43.840 which just means an object that can be placed in 0:09:43.880 --> 0:09:48.240 different positions or conditions to convey different messages, like like 0:09:48.320 --> 0:09:50.600 flag signals. Yeah, if you think about it, you could 0:09:50.640 --> 0:09:53.960 even have set up a semaphour type of signaling system 0:09:54.280 --> 0:09:57.720 with office mates where you just have a quietly like 0:09:57.760 --> 0:10:00.800 a little cabal who all know that the placement of 0:10:00.880 --> 0:10:05.760 certain office equipment or or or a coutrement in certain locations, 0:10:05.760 --> 0:10:09.000 on certain desks conveys a meaning. And from your blank stairs, 0:10:09.040 --> 0:10:10.719 I can tell neither of you are in it. Never mind, 0:10:10.720 --> 0:10:14.360 I didn't say anything. So. By the early eighteen hundreds, 0:10:14.360 --> 0:10:18.080 the United States was experimenting with a technology called helio graphs. 0:10:18.840 --> 0:10:23.040 These were solar telegraphs. They actually used sunlight and mirrors 0:10:23.080 --> 0:10:27.000 to try and send messages from signal towers. That sounds 0:10:27.040 --> 0:10:29.920 like some steam punk stuff, It does, doesn't It also 0:10:30.000 --> 0:10:33.200 reminds me of a Terry Pratchett novel in which there 0:10:33.280 --> 0:10:37.079 was a whole system set up that was competing with 0:10:37.280 --> 0:10:40.880 mail on discworld. But at any rate, they would use 0:10:40.920 --> 0:10:43.520 morse code and flash out messages to one another and 0:10:43.520 --> 0:10:47.640 send messages down the line of signal towers to get 0:10:47.640 --> 0:10:50.160 the message to where it needs to go. Then there 0:10:50.240 --> 0:10:52.359 was a guy, you may have heard of him, Alexander 0:10:52.400 --> 0:10:56.360 Graham Bell. Yeah, uh so, he and see the guy 0:10:56.360 --> 0:11:01.040 who invented Graham crackers. Uh, it was close friend to 0:11:01.040 --> 0:11:05.000 the Kellogg's. No, he invented a device called the photo 0:11:05.200 --> 0:11:09.400 phone in and it used a vibrating mirror to encode 0:11:09.640 --> 0:11:13.719 voice transmissions on a beam of light. And then you 0:11:13.720 --> 0:11:16.319 would have a selenium photo cell that could pick up 0:11:16.360 --> 0:11:19.440 that light and convert it back into sound. And it 0:11:19.559 --> 0:11:22.120 only worked in sun light. You had to have some 0:11:22.320 --> 0:11:24.800 light blasting down on this thing in order for you 0:11:24.840 --> 0:11:27.360 to get enough light to send the message. But it 0:11:27.440 --> 0:11:31.160 was really neat, and he invented this just four years 0:11:31.160 --> 0:11:34.400 after he patented the telephone. He had so much hope 0:11:34.400 --> 0:11:37.360 for this thing. Supposedly he wanted to name one of 0:11:37.440 --> 0:11:40.040 his daughters after it. He was so fond of it. 0:11:40.559 --> 0:11:45.000 Uh that wanted to name her Photo Photophone. Yeah, didn't 0:11:45.080 --> 0:11:48.160 didn't work out good thing for her. Um, maybe he 0:11:48.280 --> 0:11:54.160 could have named her photo Phoenicia. Pretty Yeah, I'm not sure, 0:11:54.280 --> 0:11:57.240 but but but it was really really cool. Uh it was. 0:11:57.320 --> 0:11:59.720 It was the series of mirrors and lenses that would 0:11:59.760 --> 0:12:02.320 dire act a beam of sunlight. And yeah, they tried 0:12:02.360 --> 0:12:04.840 it with kerosene lamp light, but it didn't work well enough. 0:12:05.360 --> 0:12:07.880 Uh so so it would direct a beam of sunlight 0:12:07.920 --> 0:12:11.280 to a mirror attached to the mouthpiece that you spoke into, 0:12:11.640 --> 0:12:14.600 which would the mirror would then bounce the light off 0:12:14.880 --> 0:12:18.120 through more lenses and onto a receiver. So when you spoke, 0:12:18.160 --> 0:12:21.079 the mirror would vibrate, thus changing the intensity of the 0:12:21.160 --> 0:12:25.120 light that was hitting the receiver. And yeah, it worked. 0:12:25.120 --> 0:12:29.400 It worked real well, very clear uh sound effects coming through. 0:12:29.720 --> 0:12:32.679 But it also would pick up noises like a like 0:12:32.840 --> 0:12:36.000 like clouds passing across the sun right because you have 0:12:36.080 --> 0:12:39.600 an interruption in the signal. So so if you've ever 0:12:39.679 --> 0:12:44.199 been wondering what that sounds like, it's probably something akin 0:12:44.320 --> 0:12:48.360 to weird static, I would imagine. But now I really 0:12:48.360 --> 0:12:51.760 want to know. This is getting cooler and cooler. Well, 0:12:51.800 --> 0:12:54.160 it keeps getting cooler. By the nineteen fifties, we have 0:12:54.200 --> 0:12:57.360 researchers who are looking into using light through cabling systems 0:12:57.360 --> 0:13:00.959 to create new communication technologies. So to get around this 0:13:01.080 --> 0:13:04.679 problem of only being able to use sunlight or some 0:13:04.760 --> 0:13:09.480 other visible light within uh the area to communicate, they 0:13:09.480 --> 0:13:12.320 wanted to be able to pass light through cabling, essentially 0:13:12.320 --> 0:13:16.200 creating very reflective cables that could pass a light signal 0:13:16.240 --> 0:13:19.160 down them. We're talking about the birth of fiber optics here, 0:13:19.559 --> 0:13:22.400 and in April nineteen seven we had the first optic 0:13:22.440 --> 0:13:25.240 telephone cable put into service. It was owned by General 0:13:25.280 --> 0:13:29.960 Telephone and Electronics. Soon afterwards, other telephone companies were installing 0:13:30.000 --> 0:13:33.200 fiber optic cables and those are really the backbone of 0:13:33.240 --> 0:13:36.679 our telecommunications infrastructure at this point. Like we think of 0:13:36.679 --> 0:13:39.839 copper as a as a signal carrier quite often, but 0:13:39.880 --> 0:13:43.800 really fiber optics are that's that's the true backbone for 0:13:43.920 --> 0:13:48.320 most of the telecommunications around the world. Now, all that's cool, 0:13:48.360 --> 0:13:50.040 but what if we were able to go back to 0:13:50.200 --> 0:13:53.720 Bell's idea of using visible light to communicate? So, in 0:13:53.760 --> 0:13:55.480 other words, what if we were to use light to 0:13:55.480 --> 0:13:59.120 transmit data through the air and not through cables, So 0:13:59.400 --> 0:14:02.240 not a system that you hook up to your computer 0:14:02.679 --> 0:14:07.120 with a physical cord, but rather light, ambient light in 0:14:07.280 --> 0:14:10.920 your environment being able to communicate data. And then that 0:14:10.920 --> 0:14:13.040 would mean we could open up the entire spectrum of 0:14:13.120 --> 0:14:18.160 visible light for communication. Is that possible? I mean, that 0:14:18.200 --> 0:14:21.680 sounds very interesting. One of the things that I often 0:14:21.800 --> 0:14:26.320 think about is all of the data that's passing through 0:14:26.360 --> 0:14:29.560 and around us all the time. Yeah, everywhere you go, 0:14:30.200 --> 0:14:33.400 there are signals bounding around. I mean they're you're walking 0:14:33.480 --> 0:14:36.120 through the range of WiFi routers, but there are also 0:14:36.200 --> 0:14:40.600 cell towers, radio broadcast towers. Yes, stuff is going through 0:14:40.600 --> 0:14:43.720 you all the time, and it's very bizarre to think, 0:14:43.720 --> 0:14:46.480 what if you could see all of that? Right, And 0:14:46.480 --> 0:14:48.280 then of course there are people who believe that they 0:14:48.320 --> 0:14:51.400 are their health is affected by these things, not that 0:14:51.440 --> 0:14:54.560 we've seen any real medical evidence to support such things, 0:14:54.600 --> 0:14:57.760 but there are people who truly believe, Yeah, who won't 0:14:57.800 --> 0:15:00.840 be around WiFi routers at all, Yeah, because they say 0:15:00.880 --> 0:15:03.680 that it it impacts their health in a negative way. Yeah, 0:15:03.840 --> 0:15:07.200 it really doesn't. These things very much are in the 0:15:07.280 --> 0:15:10.040 kind of between the microwave and the radio frequency on 0:15:10.360 --> 0:15:15.560 the spectrum the electromagnetic spectrum, and they're they're very safe there. 0:15:15.680 --> 0:15:19.680 There's a very very low probability, uh, that that they 0:15:19.680 --> 0:15:22.000 are in any way affecting anyone's health, especially from a 0:15:22.000 --> 0:15:24.680 distance of more than like two centimeters. Yeah, I mean, 0:15:24.760 --> 0:15:27.800 it's non ionizing radiation. It's just not that part of 0:15:27.840 --> 0:15:30.720 the spectrum that's going to knock molecules loose and up 0:15:30.760 --> 0:15:35.040 set your DNA. What it could possibly do is maybe 0:15:35.160 --> 0:15:38.880 heat up your skin possibly. Yeah, there there can be 0:15:38.920 --> 0:15:42.800 electromagnetic interference that can cause other issues, and we'll talk 0:15:42.800 --> 0:15:44.360 about that. And I think I think the World Health 0:15:44.440 --> 0:15:50.600 Organization has listed it as a potential carcinogen now that 0:15:51.280 --> 0:15:53.600 so you can say that. But another thing to note 0:15:53.640 --> 0:15:59.760 would be that the sun is a known carcinogen, absolutely accurate. 0:16:00.120 --> 0:16:03.240 If you're okay going out in the sun, you should 0:16:03.280 --> 0:16:06.880 probably be okay getting around a WiFi router every now 0:16:06.880 --> 0:16:08.640 and then. You might not want to sleep with your 0:16:08.640 --> 0:16:11.760 head resting on one every day. But yeah, well, the 0:16:11.760 --> 0:16:13.840 only reason I even brought it up, and I was 0:16:13.880 --> 0:16:18.400 hesitant to bring it up because pills so comfy. Because 0:16:18.400 --> 0:16:22.200 I am very skeptical of the thought that WiFi and 0:16:22.320 --> 0:16:27.480 other radio frequency communication can have a a physical effect 0:16:27.560 --> 0:16:32.120 on people, uh, particularly at the intensities of our you know, 0:16:32.520 --> 0:16:35.720 our WiFi routers things of that nature. I'm very skeptical 0:16:35.760 --> 0:16:37.560 of that. However, the reason, one of the reasons I 0:16:37.560 --> 0:16:41.320 brought it up is because it was one of the 0:16:41.360 --> 0:16:46.520 benefits that was being touted by LiFi using light instead 0:16:46.520 --> 0:16:50.320 of radio signals to transmit this data at this last 0:16:50.400 --> 0:16:54.160 segment between the backbone of the Internet and whatever device 0:16:54.240 --> 0:16:58.600 you want to use. That well, One of the many 0:16:58.640 --> 0:17:03.120 benefits is that you and complain about the wireless signals 0:17:03.200 --> 0:17:05.520 hurting you because it's using visible light. If if if 0:17:05.560 --> 0:17:07.480 that hurts you, then just being in a room with 0:17:07.520 --> 0:17:10.800 a lamp would hurt you. But at any rate, let's 0:17:10.800 --> 0:17:13.520 talk about what. So one of the benefits is that 0:17:13.640 --> 0:17:18.720 it counteracts something that is probably not a problem. Yes, yes, 0:17:19.320 --> 0:17:22.080 and that was actually my very reaction that you just had. 0:17:22.080 --> 0:17:25.800 But really, let's talk about Life I. So super cool idea. 0:17:26.440 --> 0:17:29.320 You know, it's an offshoot of a broader category called 0:17:29.359 --> 0:17:32.879 optical wireless Communications or o w C, which does not 0:17:33.000 --> 0:17:36.400 necessarily have to deal with a visible light. It could 0:17:36.400 --> 0:17:38.400 be anything in the light spectrum, so they could also 0:17:38.440 --> 0:17:42.200 involve infrared or ultra violet, something along those lines. Uh. 0:17:42.280 --> 0:17:45.320 So there is another branch, a smaller one, called visible 0:17:45.400 --> 0:17:47.880 light Communications or v l C, and Life I would 0:17:47.880 --> 0:17:51.360 be part of that. The term was coined by Harold 0:17:51.440 --> 0:17:54.920 has who is a professor and also has worked with 0:17:55.560 --> 0:17:59.720 um a company called Pure Life I to develop a system. Yeah, 0:17:59.760 --> 0:18:03.000 he's their chief science officer. Yeah. Uh, and so this 0:18:03.080 --> 0:18:05.760 is all about using light within the visible spectrum, and 0:18:05.800 --> 0:18:08.880 the reason being that he's concentrated on that is that 0:18:09.040 --> 0:18:11.760 other types of light, like infrared, can be harmful to 0:18:11.760 --> 0:18:14.879 your eyes, and ultra violet, as we know, can cause 0:18:15.000 --> 0:18:17.400 things like skin cancer if you have too much exposure 0:18:17.440 --> 0:18:20.639 to ultra violet. Uh. So he presented a TED talk 0:18:20.720 --> 0:18:23.639 on this subject, and in that talk he called it 0:18:23.840 --> 0:18:28.399 d light, which I thought was delightful. I put it 0:18:28.440 --> 0:18:30.159 in the notes and I had to say it too, 0:18:30.720 --> 0:18:34.199 uh and he wanted He used a system that was 0:18:34.240 --> 0:18:38.600 called orthogonal frequency division multiplexing or o f d M, 0:18:39.200 --> 0:18:42.359 which sounds pretty fancy, but honestly, it gets really simple. 0:18:43.040 --> 0:18:46.080 It's all about amplifying the signal from an l e 0:18:46.200 --> 0:18:49.879 ED light source, and you do that by varying the 0:18:49.920 --> 0:18:53.040 electric current that's flowing through the l e ED And 0:18:53.119 --> 0:18:55.280 that's all you need to do is just vary that current. 0:18:55.560 --> 0:18:58.080 By varying the current, you've you change the amplification of 0:18:58.080 --> 0:19:00.320 that light. If you have a receiver that can pick 0:19:00.400 --> 0:19:05.680 up these minute, subtle variations, then they can then decode 0:19:05.720 --> 0:19:08.480 that as the information that you had intended to send. 0:19:08.480 --> 0:19:10.240 So you could do this like you could send a 0:19:10.240 --> 0:19:13.320 movie this way. You could have a lightbulb that has 0:19:13.359 --> 0:19:17.800 a little microprocessor attached to it and it is pulling 0:19:17.800 --> 0:19:21.640 the signal from whatever feed is coming into your home 0:19:21.960 --> 0:19:24.080 from the Internet. So let's say that you've got the 0:19:24.160 --> 0:19:27.399 internet backbone, you've got fiber optic. Let's say that runs 0:19:27.440 --> 0:19:31.000 to your house. From there, you would have a system 0:19:31.080 --> 0:19:34.920 that would take that signal converted into the language that 0:19:34.960 --> 0:19:37.439 would be picked up by this microprocessor in a light bulb. 0:19:37.840 --> 0:19:41.919 The light bulb would then flash at the frequency the 0:19:42.000 --> 0:19:45.760 amplitude changes according to whatever data was being sent, but 0:19:45.840 --> 0:19:50.080 do so so rapidly that your human eyes would be 0:19:50.119 --> 0:19:52.720 incapable of detecting it. So we just looked like the 0:19:52.800 --> 0:19:55.959 light bulbs on. It wouldn't look like the lightbulbs. It 0:19:56.000 --> 0:19:58.240 wasn't Yeah, it wouldn't be a disco. It wouldn't be 0:19:58.240 --> 0:20:02.200 like a ghostly light bulb. Now, it would be very subtle, 0:20:02.240 --> 0:20:04.879 to the point where, because of it it's such a 0:20:04.960 --> 0:20:07.320 high frequency, it would just seem like a steady light 0:20:07.359 --> 0:20:12.119 source to us. And meanwhile, any devices outfitted with a 0:20:12.160 --> 0:20:15.680 sensor that could pick up these subtle variations in light 0:20:15.720 --> 0:20:20.520 amplitude would be able to accept that information. So with 0:20:20.640 --> 0:20:23.840 the movie example, you could have a home theater where 0:20:23.880 --> 0:20:27.640 you've got very dim lights on and you've got a 0:20:27.680 --> 0:20:32.440 receiver of some sort that can take it has that 0:20:32.440 --> 0:20:34.800 that sensor on it that can detect the changes in light. 0:20:35.040 --> 0:20:38.920 It's connected to your entertainment system, and you are beaming 0:20:39.359 --> 0:20:43.920 the film you're watching through light. There's no physical connection 0:20:44.000 --> 0:20:47.560 to the entertainment system. There's no radio connection. There no 0:20:47.720 --> 0:20:51.000 radio waves going on at all. It's just light beaming 0:20:51.000 --> 0:20:54.840 that information down, which is pretty awesome, and it can 0:20:54.880 --> 0:20:59.480 do it pretty effectively. At the TED talk he demonstrated this. 0:20:59.520 --> 0:21:02.560 He had an a desk lamp set up that had 0:21:02.600 --> 0:21:05.439 a light bulb with one of these microprocessors attached to it, 0:21:06.359 --> 0:21:09.879 and the lamp was hooked up through a system that 0:21:10.040 --> 0:21:13.479 fed it the data it needed and was set on 0:21:13.520 --> 0:21:15.960 the table. And the table had a little hole drilled 0:21:16.080 --> 0:21:19.800 into it and through that hole light would go through 0:21:19.800 --> 0:21:21.920 that little hole, and on the underside of the table 0:21:22.080 --> 0:21:25.000 was a sensor that was then connected to a projector. 0:21:25.640 --> 0:21:28.440 So he turned on the lamp and the lamp sent 0:21:28.520 --> 0:21:31.680 information to the sensor that started a video, a high 0:21:31.720 --> 0:21:35.560 definition video playing behind him as he gave his talk, 0:21:35.960 --> 0:21:39.320 And then he demonstrated by interrupting the light source. In 0:21:39.320 --> 0:21:42.480 other words, he stuck his hand over the whole and 0:21:42.560 --> 0:21:46.480 it interrupted the data stream, so the video paused. It 0:21:46.560 --> 0:21:50.040 was as if your wireless had dropped. And if you've 0:21:50.040 --> 0:21:52.399 ever had that experience where suddenly, uh, you know, it 0:21:52.400 --> 0:21:54.639 starts to buffer or it's going through like trying to 0:21:54.680 --> 0:21:56.840 search for a signal, same sort of thing. He moved 0:21:56.880 --> 0:22:00.199 his hand and it started up again. So it was 0:22:00.480 --> 0:22:02.800 an example of yes, this is live. This is a 0:22:02.840 --> 0:22:07.600 live feed of information from a lightbulb to a computer 0:22:07.680 --> 0:22:10.720 system and showing you how that information can be transferred 0:22:10.800 --> 0:22:15.080 just using light. Pretty awesome. Now, the reason you used 0:22:15.200 --> 0:22:18.800 L E. D S was specifically because L E Ed's 0:22:19.000 --> 0:22:23.000 work on their semiconductors and you can easily control them 0:22:23.000 --> 0:22:26.640 by varying that electric frequent are the electric current that 0:22:26.840 --> 0:22:30.760 goes to the semiconductors, so you can make minute changes 0:22:31.320 --> 0:22:35.040 very very quickly. And this is different from other types 0:22:35.040 --> 0:22:36.919 of light bulbs. Oh yeah, you cannot do this with 0:22:36.960 --> 0:22:40.440 an incandescent bulb, right, because incandescent bulbs what they do 0:22:40.520 --> 0:22:43.520 is you have they're essentially resistors. Right, You have this 0:22:43.760 --> 0:22:47.159 filament that resists the flow of electricity. As a result, 0:22:47.240 --> 0:22:49.520 it heats up. Eventually, it heats up to a temperature 0:22:49.520 --> 0:22:54.120 that allows it to incandesse or to glow up. Yeah, yeah, 0:22:54.200 --> 0:22:57.200 it needs that time, So that would be a rave that. Yes, 0:22:57.800 --> 0:22:59.720 if you try to use it incandescent bulbs, yes, it 0:22:59.760 --> 0:23:02.639 would not be able to transmit at near the speed 0:23:02.840 --> 0:23:04.720 of an l AED bulb. And then, of course if 0:23:04.760 --> 0:23:07.160 you wanted to do this with fluorescent lights, you might 0:23:07.200 --> 0:23:09.840 as well do the guy with the flags on the table. Yeah, 0:23:09.960 --> 0:23:12.960 same thing, because fluorescent lights, they use a gas that 0:23:12.960 --> 0:23:17.320 gets excited by electricity that then amixites another gas that 0:23:17.400 --> 0:23:20.480 then emits photons. Yeah, and those photons are usually in 0:23:20.560 --> 0:23:22.359 the ultra violet range, so you have to actually have, 0:23:22.560 --> 0:23:26.720