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Pragmatic is a weekly discussion show contemplating the practical application of technology.
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We'll talk about them more during the show. I'm your host John Gigi and today
I'm joined once again by my co-host Vic Hudson. How you doing Vic? I'm good John,
how are you? I am very very good. Is it a bit cold over there? It's not quite so
cold right now. It was much colder last weekend but it's chilly. Chilly vanilla.
There you go. Well, it's actually stinking hot over here. So there you go. I'll swap you. I like the cold bill and I like the heat
Yeah, we had a record low last week. So now we had it. We have an annoying heat wave last week, too
So yeah, I know go figure
Anyway, I'd make some and far
dismissive passing comment about global warming, but yeah, the
Individual a day by day data points do not equal a global trend. So we'll dispense with that
Okay, I just want to talk quickly about
reviews in iTunes before we get stuck into the episode.
So, the show passed another milestone of sorts this week
because Pragmatic on iTunes got its 50th written review.
Given the show is about a year old now, that's roughly one
written review every week, which is awesome.
That's pretty cool.
It is very cool and to each and every person that's reviewed the show on iTunes,
many, many thanks.
And I sincerely mean that.
If you haven't rated or reviewed the show yet
and you'd like to say thank you
or tell me how I could improve the show,
please leave a review or a rating in iTunes.
I mean, another idea, if you're using Overcast,
you can recommend your favorite episodes through the app.
You just tap the little I information icon for the episode
and then tap recommend.
It's that simple.
Now, I tend to go on cycles
when I'm asking for reviews for the show.
So this is gonna be my last one for a while
because I don't like to ask all the time.
But anyway, sometimes I've had feedback
that it's wrong to ask for reviews.
Honestly, if you want to write a one-star review, go for it.
I can't stop you and I wouldn't want to stop you.
I mean, tell me what I'm doing wrong.
That's totally fine.
Yeah, 'cause I mean, obviously,
if I'm gonna ask for feedback, then, you know,
and anyone-- - You should expect it.
- Exactly, I mean, you ask for feedback,
you're gonna get it.
Yeah, if you don't wanna feed people's feedback,
then, you know, quote unquote, don't tell me.
But, you know, that's not what I'm saying.
I want to know. And, you know, so I'm asking for feedback and I'm probably going to get it.
And, you know, and in my mind, that makes it OK to ask because it's a fair and balanced
question. So so that's all it's so it's all good is all I'm saying.
So leave your feedback positive, negative, neutral.
It's all good. And I guess the other thing is, keep in mind, look, I don't I don't do the whole
donation thing, right?
Yes, we have sponsors, but I don't take donations and stuff.
So if you enjoy listening, really, that's enough for me.
Seriously, really it is.
But, you know, and if you don't want to listen, you don't have to.
But if you do enjoy the show, think of rating it or recommending it as a donation
of a few moments of your time.
And that's all, no dollar cost, just that.
And it can really help the visibility of the show.
Plus, it lets me know what I'm doing right or wrong and how I can improve.
So there you go.
That's it. No more sales pitch.
We're done.
We'll-- and by that we don't mean we've done the show
because now we'll get stuck into it.
Drops the mic and leaves.
I'm not dropping the mic, Vic.
But that's mainly because I'm not holding the mic.
The boom arm is holding the mic.
And the boom arm seems to be quite robust.
It's not going to drop the mic on its own of its own accord.
And there's no quick release either.
So that's not going to happen either.
So I'm sorry.
Anyway, right.
What were we talking about?
Oh, yeah, that's right.
The topic.
This particular one is a request that was--
it was a topic suggestion.
So this is not just voted for, this was suggested in the topics list.
It was suggested on the 26th of October.
So it was only, well, pretty well 4 weeks ago.
So 4 weeks ago, Florian Heiber, he's a fan of the show from Germany
and he's been a fan of the show since I think almost the very beginning.
So he has suggested this topic.
And what is the topic tonight?
All about product identification, barcodes.
That's right. But not just barcodes.
Nothing but a number.
Nothing but a number. Yeah, I guess.
But not just that, I also want to talk about the more modern twist on it, which is RFID.
Okay.
So, I think it's a great topic. It's one that I never considered, I never thought of,
but it actually is one of those topics that really does interest me.
I find it fascinating and I look at the way things have progressed.
And it is definitely worth talking about and I find it fascinating.
So, here we go.
Indexing and index codes. I mean the point, okay, got to start with this. The point of indexing data is about finding something later as quickly as possible.
That could be anything from a book, a file, a record, piece of information about any of those sorts of things.
Indexing allows us to find things when we need them as quickly and as efficiently as possible.
And the first one that springs to mind when I think of an indexing system that's in mass use is the Dewey Decimal System.
and that was something that a guy called Melville Dewey came up with in 1876
and it's used in 200,000 libraries in over 130 countries around the world
but that's an example of an indexing system that's used to assist you in locating books
but obviously, and that indexing system is built on numbers
I mean, indexes can be represented in lots of different ways
obviously numerically, like the duodecimal system, alphabetically,
symbolically, you know, it depends on who or what is going to be
reading them. So for average people, we'd rather see letters and numbers
because that's what we know. We know the alphabet or, you know, if certain,
depending on the country that you grow up in, if you're from Asia or
Japan or China or, you know, then they've got different
lettering systems and numbering systems that's different from
Western culture, but it still boils down to the same thing.
It's a combination of letters and numbers.
You could do it with symbols as well.
But honestly, when it comes to technology, that's a problem
because technology and its entry level and its ability to
interpret numbers, letters and symbols, it's nowhere
near as good as our brains for whatever reason.
I do sometimes wonder though, because we're about to talk about barcodes, whether or not if people were taught barcodes from birth, if they would be able to recognize them visually, but I don't think so.
So, for a whole bunch of different reasons, it's technologically easier for you to read, for a computer to read something in a different format that is not an actual number, a written number, or a letter, or a symbol, exactly.
So, it's far better if it is using uniform squares, uniform lines, uniform spacings,
all of that stuff.
So, that uniformity lends itself to, well, the idea of a barcode.
And the thing is that a barcode, if you think about it, previously on episode 39, we talked
a little bit about Morse code.
In fact, I think I've talked about it on previous episode, even before that.
So Morse code, of course, being invented by Samuel Morse and you know, it's...
I'm all kind of rubbish, right? Okay, so it was invented for the telegraph because you're transmitting information over long distances
and it was the only way because telephones hadn't been invented at that point.
But then they started using it because it was really good for low power transmission
and it was used in the Navy for a very long time.
So, honestly, think about Morse code and what it looks like, dot dash, dot dash, dash, dot
dash, whatever, and then spacing between the letters.
If you take those dots and dashes and you sort of stretch them out vertically and you
create a bunch of lines, hey, Presto, you just created a barcode.
And it's actually true that when they were developing barcodes originally, they were
inspired by Morse code.
So kind of interesting little crossover there.
Yeah, that is interesting.
Okay, so machines of course, I guess the idea is that you want to, rather than taking a photo of an object and having the machine translate into something usable, you know, what we do instead is we will reflect light, we'll project light off onto a barcode and then we'll read that data off.
off. And then what that does is the scanner will then take that information, it'll convert
it from a varying signal of reflected light into a bunch of widths and spaces and then
it'll run it through a decoder that says "Okay, well I've got this little width here and that
gap there and this little width here, I know that's a 1." Okay, and so on and so forth
through all the numbers to figure out "Okay, well the number is like 1, 2, 3, 4, 4, 2,
422121111, whatever.
Okay.
So the how it does that is very, very interesting.
So we're gonna explore some of that.
So the codes themselves are just numbers, right?
They're just a barcode is essentially
a visual representation of numbers in a different format
that's easier for a scanner to read.
That's all it is.
So you'll see at the bottom of a barcode,
you're gonna see the numbers written.
Those numbers aren't actually read by the scanner.
They're just there for the humans. So that if you try and scan the barcode and it doesn't
work, you can then punch the numbers in manually. And that's just how it works. I mean, you've
worked at point of sale. I've worked at point of sale. I'm sure that you've had a barcode
that hasn't worked at some point.
Yeah.
Yeah. And you just love typing those in, didn't you?
Oh, yeah.
And then you get a number wrong and it's like, no, no, it's not a box. It's not a steel box.
It's the plastic box.
You know, sorry, I worked at Dixman Electronics, right?
We sold boxes. So before I get too far ahead of myself, got to start with the basics,
which is the first kind of barcode wasn't called this in the beginning, but these days it's been
retrospectively relabeled as the one dimensional barcode.
Of course, back in the originally it was just called a barcode.
But anyway. Yeah. So in 1949, two blokes,
guy called Norman Woodland and Bernard Silva
filed a patent application called Classifying Apparatus and Method.
And that described two different styles of barcode.
One was referred to as the bullseye, the other one as the linear.
And the bullseye one looked oddly like the Target logo.
It was a bullseye, you know,
although I'm pretty sure that Target didn't rip off this
circular, the circular barcode for their logo.
but still. Anyway, the linear style is, of course, the one that everyone uses and
knows. Anyway, that patent was awarded in 1952, but it wasn't really until the
Association of American Railroads attempted to use them on their rolling
stock for tracking purposes. It was in the late 60s, early 70s, but that people
sort of started to take them more seriously. But the problem was that, you
know, in the real world, you've got dust, you've got wind and rain and sleet and blah,
blah, blah. And inevitably, it caused read errors quite predominantly. So it was quite
unreliable and they actually abandoned the project. But around about that time in the
early 70s, there was a consortium, I think it was the mid 70s, the National Association
of food chains, NAFC for short, in the US.
And what they did was they were looking into barcodes
as a method of essentially identifying grocery products,
groceries, products at point of sale
that you could then easily link to a price
to accelerate how long,
basically reduce the amount of time that it took
in order for a cashier to ring up the list
on the point of sale terminal of items that you're buying.
And that was the main driving force because I see it as an attempt to improve efficiency
because the old way it used to be done and unfortunately
maybe we're both old enough to remember this was the lookup tables.
Yeah.
Yeah. So an item would come in and most of them were tagged, you know, the old tag system
that had you would dial up the little the price, the numbers on the pricing gun
and you have a reel of the tape and it had this little narrow maybe half an inch wide
little sticky thing and the little sticky thing you would simply pull the trigger on the gun
and it would, the little hammers would fire
with the numbers that you selected and it would punch out a price and then you would
in the same sort of motion you could then
sort of rub it
as it were against the surface of the product and that would put a price on it
a price on every item.
Yeah.
And I miss that.
Yeah, that's right.
Because of course, the barcode doesn't contain the price.
And so that was that was sort of the way it was done.
So it would come to the checkout.
And what they would have is they would have items where individual items were were labelled
and priced in that fashion.
And of course, the other ones that weren't, they would have lookup tables and yeah, they
would look up the table and say, OK, what is it?
It's it's this and it'd be microscopic, you know, this table because grocery stores are
huge. They'll have thousands of different things for sale.
That will depend on the size of the store, I suppose.
But anyway, and I would look through there and it's, OK, yeah, right.
It's a it's a bottle of tomato sauce, blah, blah, blah.
Done. Or ketchup, I should say ketchup, considering the listenership.
But there you go. So bottom line is it was slow and tedious.
Good cashiers would know a lot of them off by heart.
They'd know straight away where to look or they wouldn't even have to look.
But you know, and sometimes the tags would fall off and they'd have no choice but to
look it up and anyway, it's a time consuming. So anyway, the
consortium said barcodes could help us. So what they did is
they started to develop a standard and the standard is
referred to as the UPC, which is the universal product code
standard. And it applies to one dimensional barcodes or at the
time anyway, it did. So that's standardized, was standardized
as an 11 digit code, and that identifies any product as a
unique product.
It doesn't identify the product itself as, you know, if I have 10 packets
of chewing gum, it doesn't actually identify them as this is chewing gum packet
number 1006, this is packet number 1007.
It just identifies all of them as a pack of chewing gum,
probably of this flavour and of this brand.
And that's pretty much it. So, obviously, you can build
this into the wrapping or you can print it as a sticker.
And in the early days and even still quite predominantly today, it's done as a sticker after the fact
But a lot of products have it built into their actual, the actual
container for whatever it is you're buying
So the first one to do it was in 1974 and that was Wrigley's with their chewing gum
So I don't mention chewing gum, I actually don't like chewing gum, but you know, lots of people do
So there you go
Anyway, so chewing gum, yes. And so Wrigley's chewing gum, they were the ones that first
actually had a barcode built into the packaging.
But for everyone else, of course, there were just stickers.
So you would print off a bunch of stickers, stick them on and you'd be done.
You'd be all good. More and more companies supported it and made it a lot easier for the
people in the shops.
So anyway.
Okay, so the linear design, so Norman Woodland's linear design
was essentially proven to be the winner for reasons that aren't
immediately obvious, because the thing is that the bullseye one was actually more geometrically
tolerant. And by that I mean you could project it at different angles to the scanner and it would
scan more reliably from that point of view. But the downside of it, the big downside of it was that
the printing technology of the time and even today
tended to streak a little bit because you got to think about how printer works, right?
So, you've got a head, either the head is moving or the paper is moving or both are moving.
And so, at the time and even as I say, to some extent today,
as it goes past, it would pick up a little bit of residual ink as it went past.
So, when you had the circular ones, the bullseye style of barcodes,
that would tend to cause a blur and that blur would corrupt the spacing between the circles
and that would then corrupt the data. Whereas with a linear barcode, if you print the barcode on its end
that is to say the direction of travel of the paper or the ink head is such that any streaking that does occur
is actually along the length of the bars themselves, not across them.
So you're printing it vertically?
Yes, exactly. And therefore, that streaking is no longer an issue
because you're streaking onto yourself, if that makes sense.
That'd be a weird show title. Anyway, point is that these ones won
primarily for that reason, despite the fact that they were a little bit more annoying
in order to scan them, they actually worked out more reliable
from end to end. Okay.
So I talked a little bit about efficiency and that was the whole point of doing this rather than you know ringing them up one by one through a lookup table, people's memory and price tagging with price guns.
So what were the efficiency gains I hear you all ask?
Well it turns out that there was an improvement in efficiency and it doesn't sound like much but they did a lot of studies on this in the 70s and early 80s and it's about 1-2%.
And you may think to yourself, well, you know, that's, that's not much, but you multiply that by every single day over multiple years.
And if you're running stores and you have hundreds of stores all around the country, you know, even in one state that adds up real quick.
It's a cumulative gain.
Yeah, exactly. So one or 2% improvement, they'll take it.
it. So that however isn't the interesting part. The interesting part is that once
they did this it improved the efficiency and that had a knock-on effect. It
actually increased average sales. Now if you think about it, it kind of makes
sense if you're standing in line and it's taking forever for the people in
front of you to get their stuff scanned through.
You know, those items you got in your trolley, you're thinking, "Oh, I don't really need
this." Yeah, exactly.
The second guessing thing, I reckon that's where a lot of this comes from.
Of course, that's what I quote unquote, "I reckon".
OK, yeah, sure. So that's real scientific.
But the point is that this is measurable.
They measured this 10 to 12% increase in sales after the
introduction of barcode scanned products.
Go figure. Interesting. Very interesting.
Okay. So that is in a nutshell, the motivation for doing it, a little bit of history about how we got to where we are.
But of course, you know, this is pragmatic and I cannot let it pass without discussing exactly how it works.
So you may think it's straightforward.
Maybe it is straightforward, but it's still interesting.
So there are essentially four broad types of
barcode scanner, and I'm talking about one dimensional barcode scanners.
The first is called the pen type or the stylus type, if you prefer.
And these are the first ones that I saw in use was actually in a library
and they initially
were sort of common.
Well, I say sort of like convenience stores, you would see them, you'd see
them in like I saw them in use at...
It was at university, they were using these, but
in supermarket chains, they tended not to use them because a little bit more labour
intensive and the sort of thing that...
Anyway, you had to have a knack to use them.
Okay, so the idea...
Yeah, that's scary to say, there's room for operator failure.
Yeah, exactly. So, okay, I'm getting ahead of myself.
So what is this thing? So it's essentially it's a pen.
It is a pen, usually with a wire at the back, more modern ones are wireless,
and it contains a scanner and a light source built into the tip.
So what you do is you drag it at a uniform speed, and that's the killer,
a uniform speed across the barcode left to right, right to left doesn't really
matter, I think. Actually, no, it does matter.
it should be left to right across the barcode.
And if you get it right, and it's tricky to get the hang of it,
but if you get it that uniform speed right, then it will pick it up reliably enough.
But the problem is, you know, we as you know, as human beings are really quite
quite difficult with uniformity and time.
So, you know, unlike a machine that will scan at a fixed rate
every time and with minimal variability, the human arm and the human
hand won't. It just won't.
So they were prone to errors in reading, which would cause frustration
because you'd read it, the number would come up and it would say, oh, you have a packet of
razor blades. Oh, no, it's actually a packet of chewing gum.
So the reset, scan again.
Oh, you have a packet of...
I was actually, no, I'm not going to say that.
My point is that, you know, prone to errors.
OK, let's move on before I dig myself into a hole.
Laser scanner. So a rotating mirror or a set of rotating mirrors
move a laser beam at a constant speed and
when it comes into contact with a barcode, the light is reflected back and picked up by the
sensor. Now, that idea, of course, means
that the laser is scanning at a rate that is faster than an average person could move
it.
And this is one of the things that people, you know, when you move an item across a laser
scanner, people think, "Oh, okay, you've got to scan it like a certain way.
It's like I'll do a sort of like a whip in one direction.
It'll be faster and I'll go this direction, that direction, whatever else."
And they think, "Oh, they get the knack of scanning it."
And it's like, "Oh, if I scan it in this way or at this rate or at this angle, I'll get
a faster result or a better result. No, it's all about the light being reflected back and
you'll hear the little beep because the beep simply means, yes, I've had a successful scan
of the barcode. And if you sat the product on the bed, on the actual scanner and let
the laser do its thing without moving it, you would probably get a better, more reliable
result because the laser is doing the work moving it. You're moving it, it's confusing
the laser. Yeah. So, you know, and if you watch the checkout operators, you know, they
get very good at simply sliding it across the panel because they know that it'll pick
it up as it goes across the panel. Some of the ones that you'll have problems with will
be, you know, sometimes they'll have the UPC barcode printed on something with a curve
on it or if it's slightly reflective or if there's a bit of dust or dirt or grit or something
like that. And those sometimes you'll have condensation on cold stuff. Yes. That's a
a good one. Yes, condensation is a problem and they'll have to hold it different angles
to get it just so that the laser will scan it correctly. And that's, you know, it's got
nothing to do with the movement. It's got to do with, you know, the laser striking it
at an angle where it picks up all the whole entirety length of the barcode in one scan
distortion. Take distortion. Anyway, okay, so the idea is,
oh gosh, shameless. So, the idea is that, um, that idea,
sorry, has been the most preferred way of doing it
pretty much for the last 25 years. So, laser scan is good.
Okay, CCDs. Now, there are essentially two types but the
original type and still sort of popular is the single row.
they're very densely packed together light sensors,
they read ambient light reflected off the barcode
and that's the key difference, but it's also a single strip.
So the idea is it's linear in the same sense
of the barcode is linear.
And that's more cost-effective than the fourth type
which is an imaging type,
which is what most people call a camera sensor.
It's a two-dimensional array of CCD elements
that most people would simply call a digital camera.
And it literally, it takes a photo of the barcode
and then runs it through image processing software
to decode it.
And that is becoming the prevalent method.
And it's only becoming prevalent
because the decoding is becoming better, faster, cheaper,
all the same sorts of reasons,
lower power, all of those things.
And it's also becoming more common
because it's more flexible.
We'll talk about why in a minute.
So some of the key points,
The pen and the laser essentially,
they share a common problem or feature, right?
They illuminate the barcode using a specific wavelength
of light that's emitted by the laser.
So that means that their photo detectors
are specifically selected for that wavelength.
And you may say, okay, that's fine, that's good,
it's bad, maybe whatever.
But I mean, that is still something to be aware of
as a limitation of that technology.
But honestly, it's the sensor that's interesting.
So how it senses the light,
there's an excellent link in the show notes
for photosensitive devices.
It's by Ray Marston and Tony Van Roon.
It's really, really good if you really wanna read
about how those particular photosensors,
photodiodes actually work.
And I encourage you to read it if you're interested.
But before we dive into too much of the technical detail,
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So the photosensitive devices that I wanna talk about,
nice common ones, the LDR,
which stands for light dependent resistor.
That's the original technology
that was commonly used for the scanners.
Now, sometimes they're called a photoconductive cell
or a photoresistor, it depends on who you speak to.
So the construction of an LDR, you have two terminals,
they connect to each end of a strip
of photoconductive material,
and that's placed on a supporting insulating substrate,
usually a ceramic of some kind.
And it weaves its way from one end to the other,
usually in a little snake pattern,
like a zigzag of sorts.
Now, different photoconductive materials
respond differently to different wavelengths of light. Cadmium sulfide was the most commonly
used because it responds to light wavelengths that are within the human visible spectrum
and because it was relatively cheap. But I said was past tense because now cadmium is
considered a heavy metal and heavy metals are the enemy and therefore it's been restricted
in many, many countries now. So it's sort of fallen out of favor. But that's okay. Other
technologies have come along so it's all good. But anyhow, the way that it works is that
I guess, certain materials, when light, you know, photons hit them,
some of that charge will free up electrons and that reduces the resistance of the
material itself. So in effect, the bright light intensity,
as the bright light intensity increases, the resistance decreases.
So in dark environments, the resistance is higher.
So these LDRs can drive a transistor amplifier or an operational
amplifier aka an op amp and these can in turn then drive relays and eventually
that could be useful for turning on and off things like street lamps let's say
you know you want to turn on a night time and that application the other
signals are very small and you're using each subsequent amplification stage to
drive more and more power obviously that's not the context that I'm using
mean but it's just another point that LDRs are used for that purpose or can be
use for that purpose. All right, photodiodes. Now here's a little known fact, all silicon
PN junctions are photosensitive. Who knew? Well, I guess obviously someone figured that
out, so someone knew. Anyway, a photodiode is a conventional silicon PN junction diode,
in a case, but it's got a transparent cover that allows light to reach the junction. So
Real quick about silicon, you have N-doped and P-doped silicon.
One has holes, one has an excess of electrons,
essentially based on the different doping that's used.
Now, when light hits them, then
some of the charge creates holes that can carry more electrons,
which then means that it reduces the resistance of the silicon at the junction
itself. And when I say it creates holes, what I mean to say is that it
essentially the charge transfer pushes those holes to become
vacant to allow flow. It's the best way of putting it, at
least. Anyway, it comes down to the fact that the energy that's
imparted based on you know, the light wavelengths, the photons,
that the energy imparted has to be enough to overcome the band
gap for the electrons so that they can jump to the next energy
level and you can actually get current flowing. And once that's
achieved, it works like a charm. Now a phototransistor is the
same kind of thing as a photodiode, same thing but it's a transistor so PNP or NPN and same
thing it's transparent cover but the additional junction and the geometry of a transistor,
how it's physically put together, that different geometry makes them far more sensitive to
light than a photodiode.
Okay, so CCDs and imaging. I am going to cop out right there and say I'm saving that for a future
episode. Stay tuned if you care. Is there a topic all to itself? It is a topic all to itself. We'll
get to it. It is on the list. Well, whether it's on the list or on the official list or on the
unofficial list, I don't know, but it's on the list, believe me. So now we're going to get back
just briefly to touch on. So that's roughly how the scanner, the component works. So essentially
the light and the dark, you put all these things together and like essentially you can then use the
individual detectors to detect if they're light or dark and that detects whether the light that's
reflected off of the barcode. Hey presto, you can then digitally recreate the structure of the barcode
as a representation of binary ones and zeros in the scanner which you can then convert
into the actual numbers. Hey presto, you have yourself a scanner.
So a few more notes about laser scanners. They are awesome because they work over longer
distances, you know, up to a foot usually, quite easily. But the downside is they won't
usually work with a smartphone image because, well, they're trying to reflect light off
of an opaque sticker.
So some of the older scanners will not work all that well.
The newer CCD ones will work with anything pretty much because they're essentially taking
a digital image so they'll work just fine with a smartphone image.
Yeah, provided there's enough ambient light or the backlight on your smartphone is turned
up high enough because there are apps that will allow you to scan in, take a photograph
of your cards, whatever they might be, and you can then scan, display that and then as
you swipe that over a CCD scanner, it will recognize the barcode and away you go.
And that's awesome.
But it doesn't work with all of the scanners so it's a little bit of a flawed in-between
tech.
And that leads us to the next generation,
the next evolution.
Two dimensional barcodes.
Oh, yeah. 2D.
Because like we haven't got to 3D yet, but that's OK.
Maybe someday they'll do that. But for the moment, 2D is where it's at.
And everyone knows the most common, well-known, popular
two dimensional barcode is called, Vic?
The QR code.
Yes, it is. And you know what it stands for?
I do not.
It stands for the quick response code, which is a really dumb name,
but never mind that, whatever. That's what it stands for.
Let's just run with it.
We accept reality and all of its imperfections because, well,
we don't have many choices.
OK, so there's lots of different ways of doing it,
but that has turned out to be the most popular one.
It was originally put together by a Toyota spin off called Denso,
Denso Corporation.
I think it was originally called Denso Wave back in '94.
So Toyota spun them off and doing different parts
of their vehicle, manufacturing, component tracking
and stuff like that was what it was designed for.
It was the component tracking, I should say.
Either semi or fully automated vehicle assembly systems
made use of the QR codes.
Now it's instantly recognizable by it's a square of dots.
Many of the dots will touch each other
on one or more sides, but it's the three squares of which
you have a solid square in the center and a square border around it.
And there's three of them, one, two, three, usually on the top left, top right
and bottom left sides.
Although, of course, you could argue that that depends on how you want to look at the code.
It's on three of the four corners of the square.
And you'll know that's how you know that that is specifically as a QR code.
Now, the reason that you have those, those are equidistant,
they are fixed spacing.
And what they do is that they allow it to allow the imager
to compensate for three dimensional skewing of the image,
because when you take an image, the imager cannot tell whether or not the top
like the top left corner is closer to the CCD
than the bottom right corner.
And that causes a skewing of the data and, of course, corrupts the data.
So by having squares of the identical size
and identical spacing in the X and Y directions,
you can compensate for any visual skewing when it's scanned.
- That's cool.
- Yeah, yeah, they thought about it.
In fact, I just can't think about how it would work
any other way, but anyway.
All right, so the amount of data
that you can store in a QR code symbol
depends a lot on a bunch of different variables.
So there's the mode, the input character set,
and of course the version.
The version refers to the size.
So versions I think vary between one to 40,
40 being the biggest, one being the smallest.
And that affects the overall dimensions of the symbol.
So, you know, so for example, 40 will be,
you know, can several inches,
can be several inches wide,
but obviously stores a heck of a lot more information,
you know, which makes sense.
Anyway, and there's also error correction
built into it as well.
and you can have differing levels of error correction
based on the reliability required from the data
when you scan it.
The Wikipedia article is not too bad
'cause it gives you some examples.
There's also another link in the show notes
to the QR code website itself
that talks about the standards in depth.
The most common QR code that I've seen in use
is the version three.
So you may ask, so it stores more data.
Well, how much more data compared to UPC?
So we're going to take as an example, one of the most common, which is version three.
That's a 29 by 29 grid type L numeric.
OK, it's important to specify all of that up front because all of that affects how much data it can store.
127.
And this is all based on numerical digits, not talking about alphanumeric, I'm talking about numeric digits because UPC is numeric digits.
So we've got to compare apples to apples here.
So again, most common barcode,
one-dimensional barcode is a UPC type A.
So 127 it was for the QR code.
And how many for a traditional barcode?
The answer is only 12.
- That's significantly more.
- Yeah, it's huge by comparison.
So a little bit about the numbering system on a UPC.
I just had, for anyone that's curious,
The numbering system, the very first number you get
on a one-dimensional barcode
is actually refers to the numbering system.
So zero is a regular,
zero and seven are both regular UPC codes.
A two is weighted items and they're marked at the store.
So if you have a weighted item,
then you put a two in front
and a barcode identifies what it is.
Well, let's say it's oranges and you need whatever else,
that barcode will then identify it
as an item that needs to be weighed, for example,
and then calculate it based on that.
A three, yeah, yeah, they put a lot of thought into this
A three in front is the national drug or health related code
just to differentiate those sorts of grocery items from the others
A number four is an in-store use
for non-food items and the following code structure that I'll talk about in a minute
is not required, so it's kind of like a free-form flag
that you can structure the remaining 11 digits however you choose
well, remain 10 digits, the last digit being a check digit you can't use
and a five is for coupons.
The other numbers, the other preceding numbers are simply reserved for purposes
that are that I am not aware of.
So following that first digit, you have five digits, manufacturer code, five digits,
the product code, and finally, a check digit, which as Clinton pointed out in the chat
room is a checksum of sorts.
Wow, it's-- yeah.
So that's the structure of UPCA code.
Now, QR code structures are very, very different
because, of course, the data can be used to represent
a whole bunch of different things because you got so many more options.
The most common use of a QR code that people will come across is a URL.
So you can use it alphanumerically to describe a uniform
reference locator, which, you know, like techdistortion.com.
But, you know, but of course, you know, link shortness, of course, being a smart way to go, you would use a link shortener.
So the UPC code would describe the link shortened URL to save on alphanumeric size,
and then that would take you to a promotional website and hey, presto, there you go.
Pretty cool?
Yep.
Okay, so now we want to talk about the next
evolution of identification and the next evolution of that is RFIDs.
That's the trendy stuff.
And before we do talk about those, however, I'd like to talk about our second sponsor for this episode
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OK, so near field communication is technically
what RFIDs utilize.
However, we're not talking about PayPass, PayWave, Apple Pay,
Google Wallet, NFC based technologies.
and the problem with the terminology that I have is it's a bastardization, it's a conflation of terminology
so NFC refers to the method of communication
from a physically nearby radio interrogation
to a response
and it looks at it from that point of view, whereas RFID is a specific technology that's built using NFC principles
So RFID uses NFC to transfer the identification information that they're looking for.
So one is the technology and the other is the application of it?
Yes, the other is an application that utilizes the technology.
And I say the technology like NFC is a technology.
Well, NFC is not a technology really.
What NFC simply refers to is the fact that you have, with radio signals,
signals there is what I refer to as the near field which is only a handful of
wavelengths away from the source of origin of the RF energy. So near field
simply means that it works in close proximity to the transmitter and it only
works in close proximity to the transmitter because it's when you are in
close proximity to the transmitter that you can get an effective power transfer
and that'll make sense in a minute. Anyway, okay so RFID types. Let's go
through the four permutations and combinations and some of them have
really funny abbreviations. Let's start with Pratt. That's right, Pratt. Passive
reader, active tag. Of course the next one is an active reader, passive tag. Active
passive reader, active tag, passive reader, passive tag.
So we'll get go through them each one at a time.
So passive reader, active tag, Pratt.
This system has a passive reader
and it only receives the radio signals
from the active tags.
So in other words, your tag's got a battery in it
because it's active and your reader,
well, it just sits there and listens.
Active reader with a passive tag.
This is the by far the most common
and the one we're going to focus on the most in this episode.
and that is that system has an active reader that transmits an interrogation
signal and it receives the authenticated reply from a passive
device. How that works will make sense in a minute.
OK, active reader, active tag, obviously that's a combination of the above two and
passive reader, passive tag.
Well, that's a failed technology since it doesn't actually do anything because it's
far just it's passive aggressive.
There you go. Think it through.
Okay, biggest...
Sorry, I just...
It's the fourth combination, right?
Got to mention it.
No, I don't because it doesn't exist.
Okay, biggest advantages of active tags is that they allow for high frequencies
and longer distances.
Sounds like a bonus and it can be.
But the disadvantage should be obvious, they need a power source.
Even if you put a long life, low drain lithium battery in these things, they're going to
have a limited lifespan.
And honestly, these things are mass produced. They don't want to mass produce them with a
replaceable battery. So typically they don't.
So they use them for two or three years, battery dies, chuck them out, get another one.
That's the way that they tend to work.
So anyway, and that also makes them more expensive.
Now, the way a passive tag works is really kind of, I think, is kind of
ingenious. So what they do is you'll know a passive RFID tag
because it's about one inch square, maybe an inch and a half
square. Obviously, you get larger and smaller ones, but
they're about that sort of size. And you'll see a series of
concentric conductive strips on this sticker, and it'll stick to
the side of the product. Some people refer to them as a
security tag, right?
Technically, there it's an RFID tag or rather it's the same kind of technology that
you can put an RFID into it.
So, those conductors, the little pattern that they
form, what they do is they essentially act like a coil.
Now, with an electrical or magnetic system,
when you've got a rotating, alternating
magnetic field, electric field, then it'll induce a current in
that conductor, which is exactly how a generator works.
Generator spins around, it induces a current in the
windings generating electricity. So same kind of
idea. So the idea is that radio energy is an electromagnetic
wave. So the electromagnetic wave is carrying actual energy.
You can capture that through these RFID tags, through the
concentric conductors that form the antenna. And that energy
charges very, very small current, very, very small, not
much, doesn't need to be much. It charges a very small
capacitor, and that capacitor will store that energy. So what
happens, it sends out a burst.
That is, sorry, the interrogator, the reader, the active reader, it will
send out a burst of electromagnetic
radiation, referred to as a radio signal.
So it'll simply say, "Hello."
Well, OK, it doesn't say the word "hello", you know what I mean?
Although that'd be really creepy if it did.
Anyhow, so anyway, I digress.
So... - What's up?
Yo, RFID tags, what's happening?
Hello, RFID tags, are you there?
OK, that's getting more disturbing by the second.
Point is, yes, that the RFID tags, then the
charge in the capacitor then drives the circuit
and it's a very small, very low power transmitter in the RFID
in the centre of the RFID sticker, and that will then respond.
So it then transmits its response and its response is of course its own identification
So it'll respond with a radio signal and modulated essentially with its data
which is its own identification
- Who goes there? - Yeah, exactly
And it responds with its name, who it is, what it is
So the interrogation signals is on for a brief period
and then the response signal is on for a slightly longer period
but it's very low power response. And because the device is only able to be
powered by whatever charge it accumulated from the radio signal
from the active reader, from the interrogation
signal. Okay, so far so good?
Okay, cool. Obviously, RFIDs are used in a whole
bunch of different applications. Now, the one we're talking about specifically is
identification of goods at the point of sale.
But there's lots more.
Ones we aren't going to specifically talk about, but it's still interesting and worth mentioning is tracking of goods in a
warehouse, access management, that is to say access control.
And I have RFID tags on my security badge.
So my security badge, when I go into my building at my place of employment and my job,
I swipe the card and it has an RFID in it and it
responds with, "Yep, it's John, you should let him in."
Or, you know, if it's the kitchen area,
don't let this guy in,
he looks like he's gonna steal all the rest of the mints.
Anyway, access management.
So there you go.
Tracking of persons or animals.
So you, sometimes they'll put RFID chips
in a very small injectable tube
that can be injected underneath the skin
and you can literally track,
like, you know, when they chip a dog
and that or a cat or whatever, you know, that is an RFID tag and that is injected under the skin
and, you know, that allows you to be tracked, which is kind of, you know, raises all sorts of
other interesting issues we're not going to go into this episode, but never mind that.
Toll collection.
So you drive in your car, you've got a transponder in your car, you can drive through the
electricity.
Yeah, that sort of thing. Speed pass.
Here in Brisbane, it's referred to as, well, not just Brisbane, but in different parts of
Australia, you've got eToll, ePass and
Goviya. There's a whole bunch of different names of different consortiums, and
they're all subtly different, but they're all the same technology, essentially.
You know, contactless payments like your Visa card or your MasterCard or more,
you know, your new shiny new iPhone 6 or 6 Plus.
Apple Pay.
Apple Pay and your Apple Watch that hasn't been released yet.
or of course if you've had an Android phone for years, you know, in them.
So, well, not all of them, but some of them.
So contactless payments, travel documents,
you know, airport baggage tracking.
So there's so many places where RFIDs are used.
But we're only really interested in point of sale for the purposes of this
discussion, I think it's best to focus on the one component.
Okay, so the major advantages are unlike a barcode, you could scan multiple
RFID tags at the same time.
That's a time saver.
That's a win.
Oh, that's a big win.
The other major advantage, RFIDs can be completely covered as in physically covered
and they don't have to be visible to the scanner and you can still scan them.
That's a big advantage, too.
More data, too.
Oh, yes, sure. That's true. Yes, that is another advantage quite right.
Major disadvantages. In 2011, the average cost
of a mass produced passive tag was nine cents US each.
Now, if I do custom UPC labels, because I couldn't get the
and I couldn't find an equivalent mass produced cost, but if you do
limited production runs of a thousand or more UPC labels.
These are standard UPC one-dimensional barcodes.
You're looking at three cents each US.
Now that is, you know, obviously one third of the price.
Now, obviously it's also printed
many times it's printed onto the product at the time of manufacture.
but there are some stores where they want to override that for their own reasons
or you know, there's a whole bunch of reasons why they may want to.
Irrespective, the point is that it is significantly cheaper.
It doesn't sound like a lot of money, but honestly, if you're not getting much...
- Cumulative. - Yeah, it accumulates, it's a lot.
And if you're not getting much of an efficiency gain from the expense,
then why are you doing it?
The disadvantage anyway,
I'll get more about some of the other advantages in a minute,
but the other disadvantages are that it's more fragile than a barcode.
So if you get it wet, you can kill it.
Static discharge will kill them.
Nearby lightning strikes and power surges can kill them because
they're designed to accept and amplify a radio wave and capture all of that
energy. Well, it's really good at capturing static discharge.
And of course the EM pulse from a lightning strike as well.
And that'll have such a high voltage because it's uncontrolled that it can fry the
RFID chip and blow the cap. So, you know,
not good. None of those issues affect barcodes.
Okay.
So all of that's all well and good, I hear you say, but
let's talk about the whole idea of the whole multiple things at
once. Where could we get to? What's the real big benefit from
using RFIDs in a grocery scenario?
Well, before we get into that, think
about the cost problem, which is the passive tags that I quoted, the
whole nine cents each.
Those are the cheapest passive tags that you can get.
Now, they only have a small sensing range.
Now, the newer technology, the newer technology, well, that's, you know, that can
scan multiple metres, you know, 10 feet away, let's say.
But the cheap ones that I just mentioned, the ones that are potentially borderline cost effective
They have a very short sensing range
Now, you can increase the size of the tag to improve that
But obviously that increases the size of the antenna and that increases the cost
And before you know it, it's just all over Red Rover, right?
Why are you doing it? It's just not worth it anymore
So, and the problem is simple, right?
As I discussed previously on both episodes 16 and 39, you're up against the inverse square law
RF travels in an ever-expanding bubble and that sphere, the energy decreases rapidly as that expands in terms of the distance away from the source of the RF energy from the actual active reader
So it should be obvious, you have to go to a bigger one to get further away
Again I refer you back to the advantages of the active readers with the actual battery power source in them
them. Of course, you can go further away because you don't need to project as much energy.
And remember, you don't want to be projecting an infinite amount of energy because if you're
projecting an infinite amount of energy, you're going to fry the poor person standing next
to it. But it's true. You know, those PayPal, those eToll things, don't stand in front of
them for eight hours in a day, like at the side of the motorway. Don't do that. Bad idea.
Anyway, all right, it's like standing next to a mobile phone tower
at like 10 feet away.
It's also dumb.
Don't do that either.
Okay.
So as costs come down, ultimately, where we want to go with this technology
is, here's the concept, okay?
You put everything you want in your shopping trolley.
You walk through the exit.
RFID scanners read everything in the trolley.
it automatically charges your paywave, paypass, Apple pay,
payment method of choice wirelessly and you just keep on walking
out the door, done.
Done and dusted. That's the pipe dream.
Well, that's the dream. Whether it turns out to be a pipe dream, it remains to be seen.
But, you know, and it's not a reality yet, but it's getting closer.
So, as a slight tangent, just briefly,
When I lived in Calgary, and this is over a decade ago now,
the Calgary Co-op was trialing a scan as you shop experiment.
I don't know if they're still doing it, but I know that Tesco's are doing it.
And the idea is that
as you put an item in the shopping trolley, you scan it with a portable battery powered
scanner as you go. So as you add an item, you scan it, put it in the trolley, scan it, put it in the
trolley. It keeps a tally of how many of each quantity, so you scan each
wine. If you got 10 individually wrapped biscuits, well, sorry,
cookies, whatever, you would scan all 10 of them. So it keeps
tally of exactly what's in the trolley. And it's all linked
into their pricing system and can give you a running tally.
It's fantastic. However, the downside is it's all about
trust and honesty. And we're all trustworthy and honest, aren't
we, Vic?
Oh, yeah, everybody.
I'm like totally 100% honest. Anyhow, except for that statement.
So, you know, that's what the way they got around this at the
at the co-op was that they would do a random check. So you would
you would log on to the system, you would swipe your card, and
it would say, yes, oh, hey, you're John Chigi. And yes, we
you've been here three times before. And it kept a tally of
how many times you'd use the system autonomously and how many
times you had not had used the system without having essentially a shopping trolley check
at the end.
What they would do is they would flag you the first couple of times to see if there
are any discrepancies.
Even though you scanned it as it went in the trolley, they would direct you over to another
aisle and they would say, "Yeah, we'll just manually put you through anyway," and they
would do a tally and you would build up a history of trust.
It was also based on dollar value.
If you only had $50 worth on your tally list and they'd had a look in the trolley and they
that looks about $50 worth based on the cursory glance, then they would tend not to check you.
However, obviously, there's ways of gaming that system. I mean, you can hide more expensive items
inside and amongst the larger, cheaper items to make it appear as though you're good.
They just say, "Oh, I'm sorry if they do pick you out. I forgot to scan those
LED light bulbs that were hiding in the cereal box for some reason.
But anyhow, you know, it's but you can game the system, right?
Yeah. So it's not ideal.
But RFIDs would use exactly the same idea,
but it removes that trust issue because you can scan the whole trolley
and determine what's in it.
They're going to find your light bulbs in the cereal.
They're going to find the damn light bulbs.
So this is the problem.
Although there's ways of gaming that system too, you could remove the RFID tag from the packaging.
But you can't with a Faraday cage.
Well, that's actually interesting because that's one of the points.
If you have a metal trolley, that's going to interfere with the RFID signals because it is a Faraday cage, at least on, you know, five out of the six sides, unless your shopping trolley, your metal shopping trolley also has a lid, which I haven't come across one yet, but maybe there is one.
I don't think so.
So, the plastic trolleys, which I have seen in some stores and they're still they're relatively
common enough, they would be the choice if you're using RFIDs, you'd go with plastic
trolleys. You've used plastic trolleys before, I take it?
Yeah, the metal is more common, though.
Yes, you're right. Metal is far more common because it's far more robust.
You are talking about what we call a shopping cart here, right?
Sorry. Yes. Sorry.
Shopping cart, shopping trolley.
Yes. Same thing. Different name.
but yes, shopping cart, indeed.
Okay, but of course, all of that presupposes
that the RFID signals that you're reading are exhaustive and correct.
And up until now, they haven't been.
They only recently got up to around about the 99% accuracy.
And you got to realize if you got a bunch of RFID tags in physically
proximate to each other, like literally only millimeters apart,
that causes issues because they're only like
- Signal noise issues.
- Yeah, interference issues.
So there's all sorts of ways that they have to handle it.
Cause I say, oh yeah, it's possible to read them all at once.
Well, yeah, sort of it is, you know, kinda.
What you want to do is you want to avoid multiple people
talking over the top of each other.
I'm not saying multiple people, I'm talking about people.
The RFIDs are people, they're little people.
They're not actually little people, they're little RFIDs.
The point is they're all talking over each other
at the same time and that's a bad thing
'cause you can't separate them out
and then everyone's talking at once
and you're like, well, who said what?
Who are you?
What are you?
I don't know anymore.
So you just give up
and it leads to an approach where you would stagger.
So you would say, okay, I'm going to scan
all of these fellows.
So only people that start with these numbers respond,
these numbers respond and so on.
And you'll cycle through in a group based approach
and that'll reduce the statistical probability
of having a hundred responses at once.
Now there's multiple ways of overcoming that
depending upon the radio technology that they use
and so on and so forth.
I'm not gonna get into all of the details,
but there's ways of overcoming it,
but they are more expensive.
They are becoming cheaper.
It's certainly not impossible
and it is improving all the time.
And I guess that's the message.
As RFID technology improves further,
it becomes more sensitive,
it becomes cheaper and more reliable
as to say there are less missed items in each trolley,
then I can actually see this happening.
In fact, I'd wager there's probably still some in the world that are already trialing this.
And if there isn't, it's probably only five or 10 years away from becoming a commonly
trialed or even a common thing for certain supermarket chains.
Because think about it, you free up checkout attendance, it's worth the investment.
Employees cost money.
They cost a lot of money, especially when they get sick.
And you know, how dare you get sick?
I just, you know, honestly, from an employer point of view, forget
that people have any rights whatsoever to live a life, right?
Employees suck, right?
They're not productive all the time.
They stand around and they talk to other employees.
They get sick, they talk, they make
mistakes, you know, they cost you money.
Some of them are, you know, dishonest and
take money out of the tills, you know, I mean, there's all sorts of issues with
employees. So if you have RFIDs, a lot of those problems just
disappear. You don't need the checkout attendant in order to
scan the items anymore, you just push the trolley through, you
need to move some of the attendants back in the chain in
the store. So you need to have someone manning the deli and the
fresh food area, you know, or the bakery or whatever parts of
the store if your shop does have those areas, of course, some
don't. But, you know, because then they would have to put
them in a bag, program a label, put the label on the bag and say, "There you go, sir."
You know, so that so the RFID would count.
But that could save grocery shops, a supermarkets a lot in
wages, and that alone makes it worth exploring.
And honestly, that's all I had.
Did you have anything else you wanted to add to the discussion at all, Vic?
No, that covers most of it.
Well, there you go. So thank you again very much to
Florian for that suggestion.
I think that's very, there's a very interesting topic.
I hope I've answered that.
Good topic.
Gared is a good topic and I would strongly encourage listeners that want to contribute
to the show and have things that they want me to talk about, please suggest the topics.
And if I agree, I think it's a good topic, I'll put it out there and people will vote
on it and we'll pick from the list.
And that's how this one was added to the list.
So thank you again.
If you want to talk more about this, you can reach me on Twitter @johncidji.
And you can see my writing and this podcast and others I've made are hosted at my site
If you'd like to get in touch with Vic, how can they reach you, Vic?
They can find me on Twitter @vichudson1.
There will be a new episode of AppStory Podcast tomorrow for Thanksgiving here in the United
States, also known as Turkey Day.
Fantastic.
Cool.
Can't wait.
Yeah.
I'm looking forward to getting it back on.
It's been on pause for a while.
Is it a surprise who the guest is?
Oh, it's Simon Wolf and we're talking about his app, AvTag,
which should be of some interest to some people.
There's a little buzz on Twitter, you know,
about people wanting to find ways to tag
and add metadata to shows and share pieces of them
and stuff like that.
It's an app that does that, so.
No, fantastic, excellent.
Well, there'll be a link in the show notes
to that episode as well, so check it out.
Yeah.
So if you'd like to send any feedback,
please use the feedback form on the website.
That's where you'll also find the show notes
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You're welcome.
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