Frequency Hopping

These two seemingly unlikely inventors proposed a method in which allied radio operators would be able to control something like a torpedo using radio signals without fear of having their operations jammed by enemy operators. The system made clever use of the same basic technology that player Pianos used, and if you haven't heard that episode, I urge you to check it out as it's a good starter for today's

show and just a quick reminder. The system that Lamar and and Tile proposed would allow a radio transmitter and a paired receiver switch radio frequencies multiple times during a transmission in an effort to avoid frequency jamming. The trick was to create a system where the transmission antenna and the receiver could automatically tune to the appropriate frequencies on their own in such a way as to be unpredictable

to enemies. To do that, you would need some sort of instructions that both systems could carry out in synchronization, and Tile supplied this mechanism in the form of paper rolls identical to the type used in player pianos, complete with the ability to tune into eighty eight different frequencies, just as a typical piano has eight keys. So Hetty Lamar and George Antile submitted their idea to the United

States Navy. The Navy's response was less than enthusiastic. Essentially, the Navy said, we don't want to put player pianos in torpedoes, which seems like a pretty short sighted counterpoint. In a ddition, some modern historians have trouble believing Henny

Lamar could have come up with this idea herself. Some have suggested that rather than invent the approach, she simply learned about it while she was still in Austria, while she was married to Fritz Mandel, and armament manufacturer who was supplying weapons to the Nazis, but according to a nine interview with Lamar, that simply wasn't true. She said she never learned anything about armaments from her husband, who

preferred to keep his wife in relative seclusion. Personally, I think it is completely believable that Lamar came up with this idea, as she understood the potential that frequency hopping could provide for secret communications, but she lacked the mechanical and electrical engineering knowledge to make practical use of it, So, in other words, it's not like she came out of

nowhere with a fully formed implementation of her idea. The military told Lamar that if she wanted to support the United States during the war, she should stop coming up with ideas and instead she should put her fame to use in selling war bonds. Lamar, believing the United States to be on the right side of the conflict, did

just that. Her idea languished with other classified documents locked away in the United States Navy, and the reason that it was locked away was that while the Navy didn't plan on using it, they were concerned that some of this information could potentially give the enemy valuable information if it, in fact we're shared publicly, so it got put into

secret storage. Essentially, she went on to perform for troops and raise money for the United States, reportedly raising the equivalent of more than twenty million dollars by some estimates. This was all before she herself was a citizen in the United States. She was not yet a cisen but she was raising money for the US. In two the United States government, in an act I can only describe as wicked, seized Lamar's patents and labeled her an enemy alien.

Lamar was perplexed here. She had been participating in events to raise money for the United States, she had willingly submitted her patent to the United States military, and now she found herself labeled by that same government as an alien resident from a hostile country because she was originally from Austria. It was a pretty big insult on top of everything else. But Lamar kept on working in Hollywood. She produced her own film at a point when such

a thing was unheard of. The studios didn't care for that one bit, as they had a pretty tight stranglehold on entertainment at the time, and no studio wanted actors to get big ideas about producing their own movies independently. The studios liked it, with the actors being entirely dependent upon the studio, so this was not something that was greeted with acclaim among studio executives at the time. She was able to bring her mother over to the States.

If you remember, in the last episode, she was concerned her mom had fled Austria to England but had been stuck there for a while. But Hetty Lamar was able to get her mom to over to the United States, and she made a good deal of money when she started cecil b Demills, Samson and Delilah, but she would end up losing a lot of that money producing her

own movies, which would be commercially unsuccessful. She was attempting to create roles for herself because she was frustrated that studios were giving her the same sort of roles over and over, which were essentially wicked temptresses, and she wanted to play different types of parts. So she made her own movies, but they ended up not doing so well

and it almost bankrupted her. In nineteen Lamar would ask a friend of hers who was in the U. S. Navy if he might be able to find out whatever happened to her patent because it got locked away in secrecy, and she was just curious, you know, whatever happened to that idea. I came up with her friend did some digging and discovered that the technology she and Antile had proposed in ninety one was now in common use in the United States military for secret communications. Her patent at

that point had expired. So patents provide protection, but only for a set number of years. So if you have an invention and you patent it for the amount of

time that the patent is active, you have protection. If someone else uses your invention, creates something that relies upon your invention without first licensing that from you, without you giving them permission to do it, you can, uh you can pursue a legal case against them and say that they've infringed upon your patented idea or your patented invention, I should say, and if the court finds it is so,

you could be awarded money for that. However, patents only are good for a certain number of years, and after that they passed into the public domain, which is meant to give inventors the opportunity to take advantage of previous inventions and then improve upon them. Otherwise, you would lock an ideal way and it would become the exclusive domain of a single party, and that would squelch innovation. Well, Lamar's patent had entered into the public domain by nineteen

sixty nine. However, as it turns out, the military had been using that patented idea since before the patent had actually expired, and that meant that Lamar should have been paid for the use of that idea. As those who submitted their inventions to the Inventor's Counsel I mentioned them in the last episode, they were supposed to receive compensation

if those inventions were actually put into practice. Lamar was unaware of the fact that they had been doing this by the time she found out her patent had expired, and she did not know that if she were to sue within six years of the patent expiring for revenue that should have been hers, she could have won the court case. She was unaware of all of that, and as a result, she did not receive any money from her patented idea that the United States government was actively

exploiting from the nineteen fifties onward. The implementation in uh in question the one that was first used back when her patented idea was still patented, was called the Sanna buoy or Sanna boy as most people pronounce it, But it's a a portmanteau of sonar and buoy or boy I say, booie. That's just the way I've always said that word. But you know, thing thing what floats in

the water SnO. Sano buoys have been around for a while, but this particular implementation used Lamar's proposal of frequency hopping, and it would allow a buoy in the water to send sonar signals out in an attempt to detect in submarines in the area and send those communications up to

an airplane that's flying surveillance overhead. So you would actually deploy several of these Sauna buys in an area, and you would use any signals they were picking up to triangulate the position of an submarine and be able to locate them and then track them. So, in order to do that effectively, you want that communication to be secret and you want you want to avoid the potential of whoever you're trying to spy on be able to jam the signals, so you need some way of preventing that.

Frequency hopping was the way her patent had passed to a contractor who was working on the Sauna Buy. His name was rummeld Ireneus Sabor Machaki, and I know I've butcher trying to pronounce that name. It was a heck of a name to try and pronounce. He said that when he was handed the patent the names had been expunged. He didn't know who was respond stable for it. It

was just property of the United States Navy. But he used it as a basis for his design of a frequency hopping communication system between the Sauna Buy and airplanes, though his version used a computer chip to determine which frequencies the two elements would use in sequence rather than rolls of piano paper, so they upgraded the means of sending the series of frequencies, but it was still the

same idea. Years later he discovered who had written the patent, and he created a page on his personal website that he titled a Tribute to Hetty Lamar. He detailed how the frequency hopping technology was used not just in Saanna Buy's but also early surveillance drones developed by the Aerojet General Corporation and which eventually were used in Vietnam. In his piece, he thanked heavy Lamar for contributions, and as

the years went by, Lamar hit many obstacles. She would be married several times, but the marriages would never last very long. She had two children of her own and adopted another, though her adopted son would essentially be raised by another family. She would be taken under the care of a doctor named Max Jacobsen, sometimes referred to as

doctor field Good, who got her hooked on amphetamines. His medical license would ultimately be revoked by the New York State Board of Regents in nineteen seventy five, and Hey Lamar would become a recluse. She had multiple plastic surgeries, some of which did not go well, which made her

withdraw even further. She was ashamed of her appearance, and when she was contacted in nineteen seven and told that lockeed Martin and the military plan to honor her with an award for her contributions for her creation of frequency hopping, her response was, well, it's about time. She did not

attend the ceremony herself. She was self conscious about how she looked, but her son accepted the award for her, and she called him right in the middle of the acceptance speech, to the great amusement of both her son and the crowd. Old Hetty Lamar died in two thousand, at the age of eighty five, and by then her story had been told a few times, but her name

and performances had often been used as punchlines. Ultimately, I'm very sad for Hetty Lamar, as I feel her contributions were criminally underappreciated and unrewarded and unacknowledged, and the things that she was most known for were things that she ultimately thought were not very important, playing these roles that the studio kept pushing on her, not the parts that she wanted, nor her intellectual contributions. Those were left in

complete ignorance among most people, and I find that really tragic. However, when we come back, I'm going to talk more about frequency hopping and how it's an underlying technology for a lot of the stuff we use today. But first let's take a quick break to thank our sponsor. So the

concept behind frequency hopping is simple. You have two or more radios tuned to a frequency which allows for communication between those two radios, and in synchronized moments, you switch the transmitting and receiving frequencies to a different frequency but different from the one they had been using, but the same as each other, So they both simultaneously switched to

a new frequency, the same new frequency. Doing this prevents someone else from easily being able to snoop on you, or to jam your conversation, or just to encounter interference in general, because you're never on any one frequency for

two terribly long. So imagine you're listening to a song on the radio, and a minute into the song, your radio switches spontaneously to a different station, but the same song is on there, and it's playing in the exact same spot, And you find out that your radio and the transmitter are synchronized, and that if you had stuck to your original station, you'd only hear part of the song before the signal just went away and you were

listening to nothing at all. That's the basic idea. It's simple in concept, but how do you implement it so that it actually works. Both the transmitter and the receiver rely upon a pseudo random sequence to determine the series of frequencies that are to be used throughout the communication, and pseudo random kind of means what it sounds like it's a process that on casual glance looks like it's random, but in reality it isn't. I've talked about this in

previous episodes of tech Stuff. Computers can create things that appear to be random because they actually go through a very complicated system in order to get a specific product. But if you were to understand all the steps, you would see that it's not truly a random number because computers are not good at creating true random numbers. They can just simulate random most of the time anyway, So you tend to use a very complicated process, but it's

entirely deterministic. So that does mean that if you knew every single step of the process, and you had enough time and enough smarts, you could get to the answer that the computer is using. In fact, if you're good enough and you're fast enough, you could do it to the point where you could predict what the next thing is going to be, and you could actually in advance tune to the correct frequency every single time if you had all the information that the system was using in

order to generate this stuff. But again, if you were just to look at it, it would appear to be totally random because it's such a complicated system that's going through before it gets to that that solution, and the processes tend to be really super fast, like changing frequencies at least twice a second, and that's a slow one.

Most of them change frequencies way more frequently than two times in a second, which means it's way too fast for a human to be able to replicate any a Typically, the way this might work is you would have two radio transmitters and receivers or radios, let's just say, and you want them both on the same series of frequencies. So you you make some sort of process that generates what appears to be a random number, and that this number is somehow associated with frequencies, typically in a look

up table. So you could say, like, if the number is fourteen, you look at this table, this chart, and it tells you what sequence of frequencies you need to use for that communications session. So your first radio will send a request to radio number two. Radio number two responds with a seed number generated by this pseudo random process. So Radio one says, hey, I want to chat. Radio two says, use this number. Radio one ends up using that number and looks up the series of frequencies, sends

that back to radio two for a confirmation. Uh, the these are the sequence of frequencies that the two radios are going to use for the duration of their communication session, and then the radio two will confirm that by sending a synchronization signal to radio one that makes both radio start on the same moment and then they can communicate. They will swap frequencies, not just knowing which frequency it goes next, but how long each frequency will be landed upon, right,

how long do you spend on each individual frequency? And that allows for the communication between these two devices where you're you're hopping from one frequency to the next throughout the entire session. And once you do that, you would appear to be hopping too frequencies at random from the

perspective and of an outside observer. So if you and your buddy are chatting with each other over cellular phones that are using frequency hopping spread spectrum approach, then I when I'm looking at the signals that are you're sending back and forth to me, it would look like it's totally random, like there's no meaning from one frequency to the next. You're not sequentially hopping frequencies, you're jumping all over within that that bandwidth, whatever that band of frequencies

happens to be. You could be jumping left and right, you know, up and down all sorts of ways, and I would not be able to determine where you're going to go next. That's really important for a multiple reasons, not just the idea of not being snooped upon, that's

a big one, but also avoiding interference. Uh, you can have multiple devices all communicating through the same methodology, and because they're all using different frequencies and hopping around a lot, then the odds of two communication devices needing to use the exact same frequency at the exact same time are very very low. Also, these devices tend to be very low power devices, and because of that, they have a limited range. So once you get outside of that range,

you don't really have to worry about interference anymore. So two mobile phones that happened to hop on the same frequency, that's only gonna be an issue if they were really close together, otherwise the signals won't propagate far enough. And again these happen. It happened so fast, within a split second, the odds of it actually causing any real interference are extremely low, and any interference that's perceptible to human beings

that's almost impossible. So it you want to make sure that you have this this methodology set up in your system in a way that appears to be pseudo random to make sure you keep it secure and to keep it from interfering with all the other systems that are out there. Uh. One nice thing about this is that again you can use those multiple devices in that same frequency channel, and typically there are enough subchannels to allow lots of multiple devices to access the system without any

sort of cross talk or interference. So WiFi uses this. For example, when I did the WiFi episode, I talked briefly about the strategy called frequency hopping spread spectrum or f h s S. A spread spectrum is a method in which a signal is spread throughout the frequency domain of a bandwidth. So let's just say, for argument's sake, we've got a bandwidth of channels. There are ten essential essentially sub channels inside this bandwidth, so you can think of it as a highway that has ten lanes of

potential traffic. A spread spectrum would take a signal that normally would fit into just a single channel or a single lane on this highway, and then allow that signal to spread through the entire width of that bandwidth or

all of the lanes of the highway. With frequency hopping, it would be as if the car was magically jumping from say, lane to to lane seven, and then from lane seven to lane five, and then lane five to lane one, and so on and so forth, just immediately jumping from one lane to the next while continuously traveling down the highway. But there are other methodologies that take

a slightly different approach. Direct sequence spread spectrum, which is also used in WiFi, takes the signal and then modulates it with a pseudo random noise spreading code, and the result is that tiny bits of data travel through different frequency subchannels. So with frequency hopping, you have this big highway with ten lanes, and the car is in any one lane at any given time, but just one lane, right, It's like either in lane two, or it's in lane

three or whatever. And then when it comes time to hop, it suddenly appears in a different lane, but it's always only in one lane at a time. Direct sequence spread spectrum is different. It's in all the lanes simultaneously, but only tiny parts of it are in each lane, and then on the other end you're able to piece it all together. So different approach to using the same sort

of trying to solve the same sort of problem. So it's the basis d S S S. The direct sequence spread spectrum is the basis of c d M A mobile phone technology, and then the frequency hopping spread spectrum is the underlying technology for G s M mobile phones.

Most of the world used g s M for mobile phone technology, at least before the development of lte A T and t n T Mobile were the two companies in the United States that relied on g s M tech, and then c d M A was only used in a couple of places in the world, primarily the United

States under Verizon and Sprint. In WiFi, the typical approach with f H S S was to use one of seventy nine different one mega hurts channels following one of seventy eight different hops sequences, and the sequence would require hops every four hundred milliseconds. The odds of interference, whether intentional or otherwise, we're really low. To reduce the chance of interference even more, like I said, these technologies were using very low power transmissions, uh typically around one what

or less in power. And you may remember in that recent episode about WiFi how the spectrum set aside for WiFi communication happened to be within the range of industrial and medical equipment and also stuff like microwave ovens. So in the United States, the FCC had said, this band

of frequencies is set aside for these particular types of technologies. However, if your technology can transmit at a power level below one what or so, then you may also make use of this and unlicensed approaches to this this band of frequencies. That's where WiFi rose up out of the unlicensed use as long as they remained in the transmission power below

the threshold. So that also meant that the potential of interference was decreased because again those signals could not try will very far, they just didn't have a lot of behind them. H f HSS has been used in multiple types of technologies, from cell phones to WiFi to bluetooth technology, and the bluetooth implementation is actually called adaptive frequency hopping spread spectrum or a f H Bluetooth signals change frequencies one thousand six hundred times a second across seventy nine

possible subchannels. And it's called adaptive because Bluetooth can detect which frequencies are the most crowded and avoid those using less crowded frequencies to help head off potential interference problems. Now, some investimated that the value of this technology comes close to thirty billion dollars or more, and Lamar never really got to see any of that. During her lifetime. She made money in other ways, but didn't really get to

profit off this idea, which again seems to be a shame. Now, when we come back, we're gonna talk about some other more interesting, not more in interesting, but additional interesting inventions that came to us from celebrities. But first let's take

another quick break to thank our sponsor. Well, I've pretty much exhausted the topic of frequency hopping without getting into much more technical detail, and that would increase both the likelihood that I would lose a lot of listeners and more likely I would get something really really wrong, because my own understanding of the technology does not go that deep. So instead of trying to talk about it for another ten minutes and him and Hall, which I think would

waste everyone's time. I thought it might be fun to chat about other actors and other people in the entertainment industry who have been credited with various inventions and what those inventions are. For example, actor and musician Harry Connick Jr. Invented a system that synchronized the display of digital sheet music from musicians in an orchestra, so instead of musicians all referencing printed sheet music on paper, which requires you to find time to turn a page and try to

keep up with the pace of the musical piece. Harry Connick Jr. Gets a credit on US patent six million, three forty eight thousand, six hundred forty eight for a music display that keeps time with the playing of a piece and updates automatically. You file for the patent in nineteen and received a patent on February nine, two thousand two. The abstract reads like this quote, a system and method for coordinated music composition and display among musicians is presented.

The system and method enables a conductor, composer, or band leader to interactively edit one or more music score parts of a composition using a pen based interface, mouse, alpha numeric keyboard, or a musical keyboard. Handwritten music editing which is entered with the pen based interface may be flexibly converted to a digital all music notation format. Connected to the composer station are one or more musician stations that

may be arranged as an orchestra. The musical score parts may be selectively transmitted to one or more musician stations by the composer. Thus, an operator of the conductor station can flexibly write and edit music score parts and transmit the parts to musicians over the network. The system and method can also be used to conduct the orchestra in rehearsals or performances, so this could be incredibly useful if

you were composing a piece of music. Let's say that you're a film composer and you're working on trying to create just the right mood during the actual composition. You've got the film to watch, You've got a print of the film, there's no music on it yet, and you decide to try a composition you've created, and the orchestra plays it just as you wrote it, and you realize this isn't actually evoking the emotion I want. I need

to change this up a little bit. With this system, you can make those sort of notes live and have it distributed immediately to musicians who could then read those changes and incorporate that in their next performance of the piece. I think about this when I hear episodes of the soundtrack show, because they talk a lot about having to do different takes and having different approaches to playing the

same sort of music over and over again. And I think it's a pretty clever approach and also makes sense. He is a musician. He created a system that would benefit musicians. But what about magician Harry Houdini. He patented a diver's suit in nineteen twenty one. Specifically, Whodini's design was to improve upon deep sea diving suits. So this is one of those big bulky ones as the big like BioShock style helmet on the top of it. The design was meant to be an improvement in several ways

upon the diving suits of the day. For example, is meant to protect divers from the intense pressure they would

experience when diving deep below the surface. It was also meant to allow divers to quickly move up or down within the sea without having to spend as much time compressing or decompressing, And it was meant to allow divers to get in and out of the suit all by themselves, including in the case of an emergency in which a diver might need to ditch the suit underwater and risk getting the bends in an effort to avoid certain death.

The diving suit consisted of an upper body section and a lower body section, and they would join together at a metallic belt at a lever operator system on it, which would allow the diver to attach or detach the two sections. So you flip a little lever and the suit would come apart. Pretty clever invention and also makes sense. Harry Hudini was all about finding ways to get out of things very quickly. He was mostly known as an escape artist kind of magician, more of an escape artist

than your your traditional magician. I would say. Then we have Samuel Clemens, who was better known, of course as Mark Twain. He got a patent for an invention titled Quote Improvement in Adjustable and Detachable Straps for Garments end Quote, which was essentially an elastic strap and clasp, with at least one image in the patent showing a hook and clasp system. So in other words, Mark Twain, writer of Tom Sawyer and Huckleberry Finn invented the bra strap clasp.

Thank you, Mark Twain, we appreciate your support. Zeppo Marks, the younger brother to the famous Marx brothers of Groucho, Chico and Harpo. Not to mention Gummo, who most people don't remember. He wasn't just an actor in some of their earlier films. He was also an inventor. He created a cardiac pulse monitor, plus a couple of other inventions, including a heating pad that used steam as the source for heat. The cardiac monitor was in the form of

a watch. And I gotta quote the abstract because I like the idea, but I'm not sure how practical it really is, whether or not it actually worked. But here's there's the abstract quote. A unit to provide an audible and vibratory warning to advise persons who have cardiac impairment of extreme variations in the pulse rate. The unit is provided with an electric motor that is operated by the power of a small electric cell in a circuit that is intermittently closed by a pulse actuated switch and which

rotates a permanent magnet. The latter is enclosed in a housing that is held in a position corresponding to normal by a hair spring, said housing under drag of the magnetic field of the magnet being moved rotationally in the direction of magnet rotation when the pulse rate is above normal due to a more continuous energizing of the motor by the pulse, and said housing under bias of the hair spring being moved rotationally counter to said magnetic drag.

When the pulse rate is subnormal, a color coded tail tale advises of lesser pulse rate variations in either direction, and audible alarm is provided to warn of excessively high or abnormally low changes of the pulse rate. So, in other words, what all that wordiness says is that there was an element inside this watch that would rotate as part of its normal means of operation if it wasn't attached to your risk at all. Once attached to your wrist,

their pulse would create a a switch. There would be a switch that would open and close in time with your pulse. Their pulse would somehow activate this switch. This is the part where I'm not sure how this would work.

How you would have a switch that was sensitive enough to activate whenever your pulse was beating through whenever it was pressing against the switch, and whenever the switch is activated, the permanent magnet inside this device would want to turn in the opposite direction that it would normally turn in. And if your pulse was regular, then these uh counter

active forces. The natural role rotation of the permanent magnet due to the inner workings of the watch versus the actions that were being created because of your pulse closing off this switch would sort of cancel each other out.

But if your pulse was too slow, then it would be rotating too much in the way that it was naturally intended to go, or if your pulse was too fast, it would be rotating counter to that direction, and in either case it would alert you saying, hey, your heart's going all crazy, like maybe you need to take a rest. I honestly don't know if this thing would work based

upon the patent it. I didn't learn enough of it to figure out how you could have a switch that's sensitive without using something like h L e ed s to detect when blood is flowing through your veins. Anyway, I had a lot of options for other inventions created by celebrities to kind of close this out. Steven Spielberg invented a device that would allow you to make annotations and edits to a document using your voice. Um typically just a like a digital recorder that would allow you

to annotate a digital recording of a screenplay. He meant to do this so that you can make edits on the on the go, because he said, often you wanted to speak out your thoughts, but it was hard to capture what those ideas were in documented form, and this would be a way that you could collect that information

and append it to an existing document. Michael Jackson's name is on a patent for shoes that shifts the wearer's center of gravity, allowing the wearer to lean much further forward than they normally could and still maintain your balance. This was to replicate the effect as seen in the music video Smooth Criminal Now. During the music video, the dancers actually wore special harnesses hooked up to cables, and that gave them the ability to lean far forward, you know,

without face planting. But that would not be such a good idea during a live show. It would require too much set up, it would be too obvious to the audience, so they needed some other warm of invention to allow for that same sort of effect. So these shoes included a way to lock into an upstanding post positioned on a stage, sort of like a peg the shoe would fit on. This actually makes me think of action figures.

There are a lot of action figures that in the heel of a shoe on the action figure, there's a little hole, and that typically will correspond with pegs that you'll find in various action figure play sets, so that the figure will stand up and not just fall over as soon as you try and position him or her

in whatever placing you're using. But there was one invention so goofy from someone pretty famous that I felt it had to be my final example because it's just about as much of the opposite of what Hetty Lamar did as I can imagine. The inventor in question was Francis Ford Coppola, and Coppola is a famous film director and

screenwriter and producer. He co wrote the film Patent, he co wrote and directed The Godfather, and he directed apocalyp Now, among other things, so he's definitely made a name for himself in the history of film. He also has a connection with Michael Jackson. I just mentioned Michael Jackson, well Topola had a connection with him. He directed Captain e O, which is a three D seventeen minute short film that starred Michael Jackson in sort of a space fantasy adventure

and this was for Disney theme parks. But he also filed a patent application on August thirty one, two thousand six, and the patent application had the title Garment for identifying location on body of the garment wearer. The abstract is short quote the present invention discloses a garment having printed thereon a figure comprising uniquely identifiable regions that when Warren permit the wearer to identify for a third party a

particular location on the wearer's body end quote. The patent includes an image of a shirt with a turtle shell on it. The turtle's shell has a grid pattern printed over it, and the grids have numbers inside of them, so you can refer to specific numbers within the grid. And the whole purpose of this is to let someone else know when you have an itch in an effort to get that itch scratched. Seriously, this is straight from the patent application. I swear I did not make this up.

Quote for example, scratching an itch is a very common task in everyday life. It can be especially difficult, however, for a person to scratch his or her own itch when the location of the itch isn't a hard to reach spot, such as the back presently absent a device such as a scratching stick. A person with an itch in a hard to reach location must ask a second party to scratch the itch. This, in turn requires orienting the second party scratcher by using a series of directions

which are often being misunderstood by the second party. For example, these instructions might include, could you scratch lower to the left? No, the other left? Now down lower to the right, no, no too far back to the left. This situation may arise for people in normal health and dexterity, or for people with limited flexibility, such as those having spinal injuries that prevent them from bending or twisting to any significant degree.

So a solution was to have a print out of a turtle shell with numbers on it, and then you would just say can you scratch me at number seventeen. Then, because you have the shirt on with the numbers on the back, the person could reach up look at number seventeen, give you a good old scratching and you would finally

have relief. The patent office did not appear to issue a patent for this particular idea, and again I think of it as being a an incredible contrast with what Heavy Lamar's patent was back in So I had to include that as our final example because it makes me smile so much. Guys. Before I sign off, I just want to give another shout out to the documentary Bombshell.

It's all about Heavy lamar story, not just the parts about her UH kind of coming up with the idea of frequency hopping, but also other elements of her life, including the trials and tribulations she went through, the various UH challenges she faced throughout her life, choices she made, and how that affected her. I highly recommend it. If you have the opportunity to watch it, go check it out. I happen to watch it on Amazon Prime, but wherever you might find it, uh, I think it's worth a watch.

So that's a thumbs up for me. Well, that wraps up this discussion about Henty Lamar and frequency hopping and celebrity inventions. I'm sure I will someday revisit celebrity inventions. There are a couple of others out there that are kind of interesting, some of which aren't necessarily zany, but are genuinely interesting and useful. Uh, some of which are more in that zany category. So maybe I'll do an

episode about that again in the future. If you have a suggestion for an episode of tech Stuff, maybe you've got a company or technology or person in tech I should cover. Send me a message. The email address is tech Stuff at how stuff works dot com, or drop me a line on Facebook or Twitter. The handle at both of those is tech Stuff h s W. Remember to follow us on Instagram and I'll talk to you again really soon. For more on this and thousands of other topics, is it how stuff works dot com.