This video is going to be very interesting. It's going to be like an ozone blast from the past, because in a recent video i took apart this ozone generator that i thought was based on vintage ones. These ones are the vintage ones. It was a fairly modern design, but it had sort of elements to the circuitry that was modern circuitry.

It looked as though it was based on null design, particularly with the way the case was in so many bits. It seemed to be japanese. So the idea of this is that you stick three double eas into the battery compartment and when you turn it on, it's got this little ozone generator module. It's got a high voltage module inside the circuit board and then it's got spikes behind this metal plate with holes in it and when it applies a high voltage, it causes a corona discharge, not pandemic corona, but the type of corona discharge, while corona means crown it's Latin for crown, but it's a it's, a slightly visible electrical discharge, and in doing so it creates a it splits.

Some of the air molecules, apart into oxygen, very interesting, so it's used originally. This was used for fridges, uh. Well, this one says fridge care. What does this one say safe ton, but the idea is you, stick it in the fridge and uh every so often it just cycles.

It puts a little burst of ozone and it keeps the fridge fresh and stops food going, moldy and stuff like that, because it just sterilizes inside the fridge so having opened that one. I really want to see what's inside these now and these are so old. Unfortunately, the batteries have been left in one. I don't know if that's the oldest but we're just going to open these all up and we're going to see how they compare this one uh.

It feels crusty. This one is crusty. So, let's open this one first and see how they look inside and see what sort of technological differences there are. One of the main differences i'm noticing right now is that both these units have this little uh sort of air vent in the bottom.

Here this one doesn't: maybe they have simplified the case a little bit, although it does have that little channel in there which could have the same function. Let's get the screws out. So in this case, is it going to be a simpler construction other one? So that is trying to get the screws out that comes off. It's got this little thing here.

No leds that could that's kind of odd you'd expect leds behind that very similar construction, in the sense that it's got lots and lots of screws. So i think the other one is a copy. This does look like a clone of a very old product. We are talking decades old for these not just 10 years, we're talking, possibly 20 years or more, i'm not really sure there may be clues inside when we take it apart, we may find chips with numbers on them.

These are things would be ripe for usb modification, because when you've got the three double a's that totals 4.5 volts - and certainly this looks as though it's got a little packer here - that it was designed to take an external power supply. But, to be honest, i don't think usb would really been about much at that time. How do these come out? Oh, is this going to reveal stuff? Am i going to have to pop this uh little cover off? Is it got hidden screws, some of these cases and from the past they didn't really put ease of assembly first, it was like they were looking for uh, just sort of like the the style. So what's under there, nothing.

What's the bet that i pop this one off, there's nothing under here: either uh they're screws and sticky tape, it's kind of odd how long this is lingered and it's actually quite a good design. I prefer the rechargeable ones, but this one, these ones pack out. Quite a punch, whether that's a good thing or not - i don't know uh now. How does this come off? This is the usual enigma.

Isn't it these things are always quite complex? I don't think this is going to come off. I don't want to prise this up too much because the last one popped off it was. It was heat staked. Oh, is this clipped on in some way? I don't want to break it, i'm going to end up breaking it, but you know what, if i do break it, it's good that we can see what was inside there, this model versus the modern ones.

Oh, this is not. This is not going to plan. I think it may actually have to be a bit destructive here, which is not my desire. Well, it's kind of popping out what is it's uh? Have they used more sticky tape, the bastards? That's a very tight friction fit.

Do we have more screws? Oh god, we've got more screws yeah see, i think they copied the original very faithfully and just having tons and tons of screws. The last one was actually quite tricky to put together, so this one probably is going to keep the these two halves together, plus also the the cover on the other side about the screws go into it quite complex construction. They don't do it these days like this. It's just literally everything's held together by just one or two screws, so nothing terribly different about the high voltage module.

It's the same type of potted module uh this. This is also heat sticked i mean there is that little screw there, but uh previously. I found that that wasn't so critical that was actually holding an assembly together inside. Let's see if we can pop the lid off this, it will snap the heat stakes, but you know what it's just uh i want to see.

What's inside it, here's something suitable. It feels so bad doing this because it's like so old but then again without actually doing it. How are we going to know he stakes out similar assembly very interesting? Now, here's the magic! Oh, it's a traditional through-hole chip. Oh that's interesting! What have you got with crystal in the back for the and the two capacitors right? It does have some surface mount components.

I'll tell you what right? Okay, we will go deeper. We will explore these. That's interesting. 2006.

That's not too far back. Is it that's? 14 years ago, from that point, 12, 15 years ago, from the point of this video, i thought it was gon na be older right. What about this one? Once again, it will be a complete pile of screws because they all seem to be very similar. Is it going to be a similar, rip-off circuit board using the same type of microcontroller? If it's a microcontroller, maybe they used a dedicated chip back then these days it would be so cheap just to use a generic microcontroller for that.

So this comes off. It doesn't really want to come off there. It comes off revealing pretty much the same arrangement, but that doesn't mean it's from the same company. Maybe they are at the same factory.

I don't really know there are similarities, but then again that's called rip-offs. So you know rip-offs do tend to look very similar. Is it the same plastic thing it looks very similar. The circuit board inside will be the clue.

It could be that that one company was making uh units for different customers or just branding it for to look as though you know it was different brands and they would sell twice as many because people would buy the units thinking they were buying from. Oh, that's going to be quite tight, buying from a different supplier, a different vendor, as sometimes happens when in reality they were just buying them from the same company. We shall compare the cases that is not coming out terribly easy, uh. Oh, this one is not going to yield.

It's not got the glued on side panels that that doesn't matter. You have to excuse my black top nose and sniffling. It's just uh. It's not covered.

I have actually got a boring old cold, which is uh, makes a refreshing change. Everything about this is feeling retro so far, particularly that through-hole chip, that's very interesting. Is it going to be the same unit? Is it going to be the same? Yes, it is. I mean it's a different looking circuit board is the circuitry in the back the same, it's kind of the same, it's covered in shmoo under there, okay, righty righty-ho uh.

One moment. Please i'm going to explore these reverse engineering is done. Let's begin the exploration, i shall zoom down this just a little bit. Oh, that was way too much, but not to worry.

This is where we are. I think this is the design date tcm 99, 38, 1999 38th week, and the chip here has what looks like a date code on it, which could suggest the 16th week of 2000. So this could date back to the millennium. This particular one, that's the oldest of the two.

It's got a couple of buttons: it's got a 47 megafire capacitor. I believe in this case it's actually 100 mg fart, and it's got this led that says green and red, but for some reason they've got they've done it from the other side circuit board. So, while they've been designing, it green is in reverse and red is spell rde and it's in reverse. The elan microcontroller is an em78p156elp and it's a one-time programmable microcontroller for through whole use.

Okay, that's this side done not much on it. On the other side, we have pretty much the same as this. This is the new one. This was this is available on aliexpress right now and they ha it has evolved, but um.

The only thing that's really changed is they've used a different microcontroller, possibly the same from the same sort of range, but a more modern one, but they've actually shuffled it. They've put the surface mount uh chip in this side and the crystal, which was actually tacked in this side, on the back of where the chip is, is actually on the sort of main component side of the other circuit board. So what do we have? We have the power coming on. We've got the common positive for the high voltage module for the ozone.

We've got a transistor to switch it. That's, it switched via a 100 ohm resistor up here we have exactly the same voltage. Sensing circuit is this. That means this.

Has just been copied and copied and copied they've said it works, let's not change it. We've got a reset circuit, which is unusual, a 10k resistor and a 100 nanofarad capacitor, which provides a reset signals. Processor, a couple of 10k pull-up resistors for the two buttons here um, and that is more. There are some odd resistors there's this resistor here and these two here i'll show you them on the schematic right.

Tell you what let's just cut over to the schematic itself, and then i will give you incredible deja vu by showing you the previous schematic of the uh of the new version. So here's the three double a batteries providing us 4.5 volts and the zero volt rail. Because it's fairly busy here, i've drawn the little block for zero volts. So that's zero volts and that's your volts as well.

There's the 100 microfarad capacitor 10 volt um and there's a 100 nano fire decoupling capacitor, just purely to provide a nice stable, glitch-free supply for the microcontroller. Let me just put in those little dots i missed out - that's just me being pedantic now and so on. Yeah. I forgot the darts.

The input to the unit from the two buttons is two ten key resistors pulling up to the positive rail and the two buttons just bridge that to the zero volt realm. There's the crystal, with its two load, capacitors, to provide a stable operating frequency. I'm going to guess it's 32.768 kilohertz the standard watch crystal it's, not that critical, really there's two leds with two 470 ohm resistors um and then there's this uh odd arrangement. They've got a 10k resistor going to positive for the 10 pin 10..

I'd normally expect that to be a memory, clear pin, but our reset but uh - it's not in this instance, not sure what it is even look at the data sheet. It wasn't really obvious. There's also one mega ohm resistor pulling pin 11 to the zero volt rail and a 430 k resistor pulling pin 17 to the zero volt rail. What is interesting is that the next step along this circuit board here, which i reckon is from 2006, uses the same microcontroller slightly different logo on it.

They've switched back to the 47-megafar capacitor and they've just got rid of those three resistors suggesting. Maybe there were test values, maybe they were experimenting with values: programming values from outside there's 100 ohm resistor driving this transistor switch on the ozone module which basically generates the high voltage and then applies it to the spikes when it switches the ozone module on it. Also switches on the power sense circuitry, the voltage sensing circuitry, which is a voltage divider, a pnp transistor. If the voltage is high enough, if i'm getting this right, the transistor will be turned on because it will effectively pull uh the base of that resistor that transistor low, so it'll turn on and this pull up resistor will uh.

Then it will be pulled up to the positive rail, and that will signal that to the chip that the battery is good. When the battery goes too low, the transistor does not turn on and uh. Then that means that the uh pull down resistor here then signals to it when it goes negative that uh that the battery is low and if you want the deja vu, let's just zoom out here, there's the new circuit, here's the old circuit! No here that's the old circuit that this is the new circuit and the most recent one, the surface mount chip. Let's compare them actually i'll, just zoom up, because you know it's otherwise, it's going to be tiny and i'll.

Show you what the difference is so i'll. Zoom up in this there's the batteries there's the 47 megafire there's the 100 nano capacitor there's the microcontroller. Everything else is pretty much identical: higher value resistor for a more sensitive transistor here. Everything else is the same.

Apart from that 22k resistor and the a new one used to be a 20k resistor and the pull-up for the buttons is now incorporated into the microcontroller a couple of different resistors for the different sensitivities of the leds, and then that's it. That's really fundamentally the only differences and those missing resistors, but having said that, those resistors were missing on the 2006 version. I should write on this one now. 2020 version 2021, this era, so it does appear that this is just the reincarnation of a really old design that dates back to the millennium, that you know the lasts of millennium uh.

It makes it sound, really old, doesn't it, but it's just kind of like they've prob they've not made it simpler. They've they've made the case just as hard to assemble. The circuit board is roughly the same same shape with the different positioning and the modules. The same.

There's really very little difference. They really actually have said you know if it works, don't mess with it. So there we go it's nice. When you get things like that, that they've said you know it is expensive to make with all that extra assembly all the screws.

But you know what it's, how we've always done it and it's how we'll continue. But i wonder if it's the same company making them or if it's a different companies, this one says ht in the back, but that's not echoed in the world the other one. The only reference is tcm, but that's possibly a designer thk, don't know version one, not sure, but there we go stuff um. I've just said.

I just said: i reckon that's. 2. 000.. Maybe that's uh! Oh! Is this another version because this says 2006.? Oh, that's not helpful, is it so that i thought that was zero zero but because it was a bit smudgy.

Maybe it's a zero eight. Maybe this is the more recent one. That's had those extra resistors put in and maybe they've used that just to give other features, i'm not really sure that's strange. It's not.

The microcontrollers are not something. You'd want to use these days because uh they're, probably not as standard as you know, the usual picks and well the product microcontrollers, which is what you'd use now, there's a very good chance that they did use a modern version of this. I don't think they'd rewrite the software, but maybe they did. Who knows another thing is this one here one of them had the ross sticker on it reduction hazardous substances, this one, this one didn't which makes me think yeah.

I thought this was the yeah. That's kind of messed up, it's a whole mishmash of random designs, but there we go. That is it when you buy one of these little uh, refrigerator freshening devices from ebay and ion care, this one is called what you're actually getting is a something that is not new. It's a really old design - that's been around for about 20 or so years, so that makes it kind of interesting.

It means that you know it's been good enough, that it's lasted this long, so that was interesting well worth taking apart and exploring this of different evolutions of the circuit.