Hi, welcome to tear down! Tuesday Today we're going to take a look at one of these omnidirectional barcode scanners that you've no doubt seen and used at your local, uh, supermarket checkout or something like that where you just wave the product in front of it and it scans the barcode at almost any angle so you can probably see sort of stuff rotating in there and puts like a laser pattern. and it can read the barcode in any direction. So what's inside of these things? Well, let's find out now. this is a symbol brand one.

They used to be a real topnotch, but they got bought out or acquired by Motor Roler or something like that, so this one is still available. This model is the Ls9208, but it's available as still the 92808, but under the Motorola brand. so I'm not sure if it's if it's exactly the same. So although it's 96 vintage, it's was pretty much state-ofthe-art at its time in terms of omnidirectional, uh, barcode scanners, so it should be fairly representative of the technology.

Now you're probably familiar with these uh USB line scanner ones. You can pick these up on eBay for like 20 bucks or something. They're super duper cheap and basically by line scanner it's pretty much you can see the laser there. It just does a single line.

so if you go like that, boom it. It just reads sort of these one-dimensional or line based barcodes. but these ones are omnidirectional. Let's take a look at the pattern in this one.

now. It's actually quite hard to get the pattern of this one on camera because it's not, uh, very bright at all. But you can see that it pretty much has multiple scanning lines. It's still a line based system so to speak, but it has multiple lines in all these different axes like this going.

so one's going down like that, one's going down like that, and then scanning across like that. and then one's scanning up and down, down like that, and across and across in all those different angles. So it can pick up the barcode in pretty much any orientation. So no matter how you wipe the product in front of the scanner, it's going to pick it up.

So with your traditional line scanner like this, you have to bring it down and then over the code like that. if you bring it down of course, in that direction, it's just not going to read it at all cuz it can't read the pattern. But with these omnidirectional ones, you can read them in pretty much any orientation. You can bring it down.

Wh? Bring it in like that. Bring it down like that. Even on a really small angle like that. That is a ridiculously shallow angle.

and it's still reading that. No, there's no barcode on the back there. It's actually reading that. And you can come in at an angle like that and it gets it.

So you can just pretty much just wipe the thing in front of it. and you're used to doing that at your checkout. and it's that omnidirectional scan line pattern that makes it do that. and similar to the these USB based ones which just basically simulate a USB keyboard.

so it's just like you typing these symbols in your software doesn't know any difference. You don't need any fancy drivers or something like that. This one is what's called a Uh Keyboard wedge device I.E It wedges in between or in series with your in this case an old style PS2 keyboard. And of course here's the power coming in from the Um external Uh Power plug pack for this thing and it just simulates the key presses.

Uh, you know. so it basically can work with any software or any point of uh sale system. But on top of this keyboard wedge option, uh, you can also get a USB option as well and an serial Rs232 and some sort of custom IBM uh protocol interface. and I believe all the hardware is built in here.

you just require a different cable. Look, it's got like an RJ45 plug on here, but I only have the cable supplied for the keyboard wedge here, but you can actually scan in different Uh barcodes. This is what they give you in the manual here and you can actually configure the device after you powered It Up by. oops, Um, actually scanning the particular barcode you need and setting it up that way.

It's quite a clever way to do it So I can configure all sorts of stuff like this from the manual by just scanning in the particular uh type. So it's going to be interesting to take a look inside this thing. and we're obviously going to have Motors and mirrors spinning around and all sorts of jazz to uh to make those multiple lines. So according to the specs, it's got five different scan angles and four lines per scan angle at a 4 Herz raster rate.

So it can scan those at four times per second in those angles. So let's take a look at it. All right, let's crack this thing open. There were just two screws down in there and presumably yeah, it's just going to pop wh something's falling out.

That's the RJ 45 Jack connected via a little flat Flex ribbon. But there we go. we're in. like Flynn look at that straight in.

and doesn't that look gorgeous? That looks like a gold reflective mirror in there. Oh beautiful. now. without even powering it up and seen it in operation, it's fairly obvious how this works here.

Here's our laser diode here, mounted in this big uh, diecast alloy bracket. here. probably got some heat sinking happening on there I'm not sure the output power of the Uh laser diode? what is it 1 M or something like that And the manual says this is a Class one laser diode, which is what you'd expect. It means it's basically, uh, safe in all uh modes of operation.

pretty much which it would have to be you know, being at a consumer. uh, checkout Point here. But basically, and they've got the laser diode mounted in here and it's a long way. reflected off this look, You can see it shooting out there like that, reflecting off that in a spot right in there and then that just bounces around.

Then that bounces off this mirror down in here like this. and then it bounces off the five different segments that we got 1, 2, 3, 4, five. So there's our five different segments. So if our laser diode here is fixed, it's shock mounted.

Check it out. It's actually uh, the whole. Well, the whole Arrangement is uh, shock mounted. So you know when you throw products down on the bench or something like you know on the counter, top it.

the vibration doesn't come through to the Um scanning Optics in there, which you know is a big deal when you're using it in a consumer point of view. you know vibrations can easily go through this bench if I sort of throw something down on this bench next to it. All that vibration and shock is going to come through into the electronics so they got those nicely decoupled in there by way of these uh, shock mounts there there and there and there. the entire system.

So we've got ourselves a fixed laser diode module here. screw adjust there so they they can tweak the angle on this thing after they've actually produced it. Then all of our scanning is done by this mirror down in there and you can. Yeah, I can move that by hand.

Oh, look at that. It's a prism. Look at that. That's terrific.

Wow, look at the sharp point on that. So obviously it's all in the timing of course. So the Um. optic output from the sensor would have to, uh, well, is timed with the mirror like this to actually get, uh, the reflected image back in there from each particular angle and then scanning that so we can actually power that up and watch this thing spin around.

That'll be terrific. Woohoo! Love it! So they don't really have anything fancy. That's a neat way to get all of these different scanning modes as you can see five different angles with five lines per mode on this thing. So it really is, uh, rather amazing.

And there's our photo diode sensor down in there and it's got a shroud on top. We can. probably? yeah, we can peel that off. There's no, uh, part number or anything like that in there.

but uh, there you go. and uh, that is. There's nothing fancy going on there at all, but you can see that there is some extra filtering going on in that thing. Here we go.

I'm going to power it up and uh oh, there we go. there we go. Our mirror is scanning down in there and yeah, you can see some of the uh yeah, you can see the laser shining off there like that. Beautiful this mirror up here.

I can if I put my finger on that I can actually feel that I'll get in there with my macro lens and see if you can see that move and there you go. Hopefully you can see that mirror bit of shimmy in that mirror if I turn it off. There we go go and I'll apply power and it's starting up there. It goes.

Just the tiniest little amount of wobble in that mirror. so I'm not sure how they're coupling that through. There doesn't seem to be a motor there. They might be getting some sort of vibration through from the other one in some sort of clever way.

H So I'll show you what happens with the scanning pattern if I actually stop this mirror up here with my finger from vibrating. So let me see if I can get that pattern so that's normal and let me put my finger on the top of that. Here we go. you can see I can physically stop that from scanning across in that direction like that so the you can see the speck is correct, right? We've got five different angles there with four lines per angle and and that it's scann at a rate of four times per second.

And that's about what it looks like. So yep, Spec confirmed. And that prism down in there. It's got four sides on it, but they're not identical.

They're all angled slightly differently even though you probably can't see it. And that's how you get your four different scan lines that you get in the spec so you know they might have a lesser model that might. And you have three scan lines. For example.

Well, that one won't be a square, it'll be a triangle and would love to be able to show you. uh, how? the angled mirror in there, the rotating prism, the the foursided, uh, angled plates actually give you different scan lines. but unfortunately, if I stop that motor, then it actually, uh, just switches off the laser so it obviously senses that there's an issue and and switches it off. So unfortunately, unless I uh, bypass it, jewy rig it somehow, then uh n it's not going to work and I can show you that by sort of slowing it down a bit.

Here we go. maybe let's have a look wh there we go I just switched the laser off, switched it back on. There we go n but it's uh, certainly fun to just apply your finger on the top vibrating mirror there and I can just get the and I can just scan that manually slowly like that. That's rather neat, but those four lines there 1, 2, 3, four are determined by the four different Uh angled surfaces on that rotating prism.

Now what I'm going to do is I'm going to test if this laser diode here actually has any functionality as part of the scanning process. So here we go: I've got my barcode on here and I'm just going to scan that in there. We go. Okay, no problem whatsoever.

and I'm going to block off my laser diode with my pointer here and look at that. No, it clearly can't read that barcode and no matter how many times I do that, I cannot get it to even beep or scan that thing once. So obviously the laser diode is a very critical part of the illumination mechanism for Illuminating the barcode so that this thing can pick it up and probably no one. I mean I'm a little bit surprised by that actually.

I Thought, you know it may have actually still been able to read the barcode using ambient light or something. but clearly what's happening is that the laser is scanning across the barcode like that and then they're filtering that and with the Uh lens on the front and they get in. The difference between the dark oh, I.E it's going to reflect off the White surface and it's not going to reflect off the dark surface. So that's how they can get the ones and the zeros and identify the Uh bar code on that particular thing.

So there you go, that laser diode and the vibrating and the scanning and all the different angles. That's a critical part of the illumination of this barcode. It simply does not work without. It doesn't work with just ambient light.

So that sensor in there I mean you probably could tweak it to get it to work under ambient light conditions, but it's obviously much more reliable. uh to get the contrast required by uh, lighting it up with a laser diode like that? Okay, let's try that again, but in dark, it's not completely dark. Here on the lab, you can see the Grain on the camera image. it's really, uh, gained up on my camera.

but it is pretty dark in here, so let's yep. no problem whatsoever. There you go. and if I make it even darker, I'm I'm putting my Uh jumper over the top of this whole thing so it is pretty Pitch Black in there and no no problem whatsoever.

So that illumination system works fantastic. and likewise, in bright conditions. give it a test. Here we go: I'm going to shine my torch onto this thing.

so I'm really overexposing that and yep, you can still read that even under really bright light conditions. All right. What I really want to see is how they're vibrating this top mirror up here. So um, let's try and get this whole hey hey I think yeah, look at that just comes out as one big thing.

We got some, uh, soft padding in the back there and aha, there you go. electromechanical vibrator in there and that's just transferring that through to the top there. There we go. That's what I couldn't see before there was that bar.

Well, I could kind of see a bar going down, but I thought it might have been maybe tied to the other motor or something. but no, there you go. It's got its own little, uh, little vibration coil there and uh, a couple of more little, uh, shock mount things there and that's about all she wrote. There's a little, uh, DC motor in there and yeah, that's not just, you know, they're not just ramping that up.

they're uh, controlling the speed and getting. uh, probably getting the timing from that thing as well. and this flap they've got on here. This is obviously just to stop ambient light coming in, swapping the sensor from the front there so you're really only want the image reflected off that mirror at the back.

And we haven't got a huge amount of chips here on our board. But let's uh, go in there and take a look at what we have. Bam Bam Bedrock 2 chipset presumably Pebbles There you go. so they're a fan of The Flintstones So um I don't know we'd have to look up a number on that, but could be one of the uh custom devices for uh, particularly for uh, decoding the sensor and getting the barcodes out H obviously doing some sort of heavy custom processing there and no, unfortunately, I can't find any info on that at all at of first.

uh glance. all I get is like a whole bunch of broker uh, websites which may possibly have it. but uh, no data sheet or any info like that. So if you do have any info, please leave it in the comments.

aha main processor down in there Hatachi H8s old school and likewise that one STI branded again, but I doesn't bring up anything at all. Can't find anything on the search there so I don't know, um not a huge amount of IO on that thing. lot of uh Power and decoupling there I don't know. is it some sort of serializer or something like that? I don't know I'm just completely guessing.

no idea, but obviously designed to match this STI chip over here and nothing special down in there. We just got a 74 series 240 uh logic from TI There's our Crystal oscillator another one under here that has a firmware uh, lay on it, so presumably a programmable device. Let's take a look at that one too. Aha, look at that.

We got ourselves an old at Mill At91r 4042 that's an Arm 7 uh, thumb processor that was pretty decent and grunty. Uh, you know, back in the day 1996 when this thing was done. So uh, there we go. It was manufactured the 53rd week, uh 05 there.

So there you go that's obviously doing the heavy lifting. so sort of like the image up Pro processing and stuff like that. So maybe this uh, chipset this custom, um, you know, Flintstones chipset in here is, you know, probably just doing some sort of uh decoding or something like that. but probably a lot of the decoding in real time done inside that Atmail Arm processor.

It makes sense cuz you got to do a lot of processing here. especially like the five different angles all in real time. four times per second scanning that image So this could be some sort of like a contrast image recognition which like converts it into a more usable form like filtered form that the Atmail processor can then uh, process in real time and try and get a barcode out of it because you can program in like it's not just searching for one barcode as well as all the different types. You can actually program this with the uh software.

you can hook it up to a PC it comes with software and tell it to read. You know, 50 different types of barcodes. so if you enable all of them to be scanned then this thing has got to do a lot of work. I mean I don't envy that thing having to, you know, process all the different angles and do all that and search for all the different types of barcodes.

It's crazy, so no wonder they had to put an arm processor in this thing. this uh one over here. of course, the Hatachi H H8s. That's just you know they're probably just doing some interfacing all that uh protocol, um stuff the uh us cuz this has presumably a USB uh interface so it just be doing like the in face work pretty much with uh, the RJ45 here cuz you know you don't want to do that in your arm processor here.

just offload all that interface and protocol stuff over to here. but image processing there and protocol so that's nicely segregated I don't mind that at all. And on the back of the board here, there's a fair bit of passive work going on, but no sort of, uh, heavy duty processing at all. But this is interesting how they've added this uh, flat FL copper Shield over here and solded that on to part of the tabs, so they obviously needed some extra shielding on that, so that's clearly some sort of afterthought there.

I think maybe it didn't pass. uh EMC compliance and uh, whoops, let's just, uh, whack that across there. There's not a huge amount happening here. There's a classic Lm358 opamp and we got some 74 series logic HC 4066 there absolute classic and uh, what's that little puppy that 8 Pin so package next to it Hm, but that there's all part of the uh laser Drive circuitry there cuz there's the laser connector on it and uh, this is all motor Drive stuff over here.

Here it is. So this is all motor stuff around here. and uh, that's about all she wrote. Really? Now that right there is a fascinating package.

look look at that. Can anyone tell me what that is? Look at that. some sort of opto coupler perhaps with a split going right through it that is very and then potted. Like you know, two different halves potted.

That is a fascinating package anyone? Now look at that. I Do believe there's another filter on the entry and that doesn't surprise me at all. really. Because you got to get that contrast.

you have to get that contrast with the Uh laser diode against the bright and the dark patches on the barcode, you can see how this is clearly like an afterthought. I Mean they've even put the product uh, barcode on the bottom here and then they've just tacked this on, um, to, you know, to put a bit more shielding. Or maybe they forgot the ground between there and there or something like that and they're joining them together and that was a way to do it. But H there we go.

We can get a real good look at that rotating mirror in there, the rotating prism, and uh, it looks to be a slight curvature. Or is that my imagination? No, no, that could be an optical illusion that there's a slight curvature on that thing I Think it is actually a flat surface and uh, that is really? Jazzy I Like that Woohoo! Sex on a stick. And there's the prism in there and you can probably just see how that some sides are angled slightly different than the other. like that one is greater than that one there bit hard to see, but yeah, there's just a mild angle difference in those and you'll notice that the top of the prism here has this reflective.

There it is. It's reflective. We can see ourselves in there. Hello there! I Am.

And so it's got this reflective square with something in the corner here. I Don't know if it's it doesn't appear to be a magnet or anything like that, but clearly they're doing this. and the rest of it is matte black. So obviously they're getting some sort of optical thing happening there.

They need that surface reflective so that they can get the positional rotation of this thing. So that's got to be what this mysterious device is doing here. It's obviously detecting the positional because this is the bottom side of the board. so it's detecting the rotational position of that uh, mirror on there as it goes around.

So how it's exactly doing that? not 100% sure, but my best guess would be that that is maybe a UV lead there and then reflecting off into a photo. uh, diode here so that when the reflective surface comes around boom, it bounces off and it knows the position of or at least the start position of that mirror. and then you can calibrate that in software of course, so that's probably what's going on there. So I'd love to get a little data sheet for that thing, but that seems like the most obvious thing that's happening.

And if we probe our motor here, this is our Uh for that prism. There we go. we're getting about 147 Hertz or thereabouts little bit of Jitter on that you can see as you'd expect. In fact, I can, probably, uh, get the Uh histogram data up on that.

There we go, we're getting a standard deviation there of Uh 600 MZ or thereabouts. So there you go. That's the clock driving the Uh rotating prism and that's the drive signal for that uh top coil on the uh top mirror that uh, vibrates that has that vibrating uh shaft going up to it and that's about 33.7 Herz or thereabouts. So there you go.

I Hope you found that tear down interesting of this omnidirectional scanner and uh, unfortunately, we can't go a huge amount further. I Don't think without any data on that Flintstones Uh chipet exactly what it's uh doing in there. So if anyone's got any data on these things, then uh, please leave it in the comments. But there you go.

That's how one of these Omni directional barcode scanners work, and they're quite neat. There's a whole bunch of uh, you know, laser and Optics and mirror Optics and uh, stuff going on there and uh, lots of data processing and uh, filtering and things like that to give a rather clever solution to scanning those barcodes in pretty much any orientation. I Love it! Woohoo! Vibrate! Oh I Can play with this all day long. Catch you next time.