I had to buy this and get it shipped from America because it's New Old Stock Very interesting atomizer system for putting a room into the economy or fresheners. volatile organic compound introduction units. They basically put a haze of oil into the air I think that's what's in this and let me show you the way this one works because it's quite interesting. I Did manage to buy some of these in the UK a long time ago, but they're kind of obsolete now.

I Don't know why they went obsolete. Maybe they were unreliable or something. If you watch the output of this, you'll see every so often a little puff of Hayes Did you see it's not very. It's not very visible.

I'll try again because it does it roughly every eight seconds when set to the highest setting. Did you see that time? not Puff So what's actually happening here is that there is a little tub of the liquid. it's very concentrated. it lasts for a long time and only tiny corn disk come out are given pulse and there's a battery.

I Did ask the seller to remove the battery which was out of date. Uh, its end date was 2005 and this is 2023 when I'm making this so it was very old. I Unfortunately didn't remove the battery, but it's notable that it was the older technology battery that had not leaked even though it had been in there for a long time. Well, there was a little bit of ooze around the end, but it wasn't bad.

It certainly hadn't damaged the contacts, which is good. Uh, also because the battery is in there, it broke off one of the tabs that holds the battery in position. Now if I hold it up like this, you can see a little atomizer disk. But you know what? Let's get straight into this.

So I bought some of these when I was young. Let's see how it comes out. I Do remember it's quite difficult to get out back then because it kind of Clips in in an odd way. I don't know if I'm better removing this base plate if it actually pops off.

I'm going to be careful here in case of damage. The little disc, because it's not is standard atomizer disc. Oh, here we go, here, we go. Oh, and the whole thing is coming off in one assembly.

This is good. So what we have unfortunately is a blob. but I do remember the blob being there in the when I got them in the past and I remember the switch and the inductor right? Let's be very careful about this. I don't want to break I want to put it back together and then try it with other random liquids.

The main thing about this is I want to reverse engineer because it's a number of these devices that somehow manages to use uh, single, double a cell to power the circuitry. This is not coming out. Let me just apply a little bit of pressure up here and see if I can push it out. No, it doesn't want to come out.

I Shall get it out though. and then we'll take a look at the socket board so it's got our Reservoir capacity. There is a little step up inductor. Didn't realize that it's got a primary and a secondary.

Uh. also another little inductor here. Is it boosting the voltage up for the circuitry? This is interesting. Write a whole I Think it's time to explore one.

Oh, they've rubbed the number off the bastards. Why do they do that? Uh, but anyway, time to explore one moment. please. Reverse engineering is complete.

Let's explore a very interesting circuit. So interesting I Had to crack out the keysight oscilloscope. Just ignore the data up here. it's not set and uh, actually monitor of what was coming out of this and it's uh, it's a complex little circuit.

It's very clever. so let's take a look at the component side. First look at the multi-position switch for the five different Aroma levels and it just varies the timing between each pulse. It doesn't vary I Don't think it varies the length of pulse, but just the gap between them.

and this has a five outputs, but only four of them are used and it just knows the middle one which is not connected to anything, just must be the middle one because there's nothing coming back in the other pins. There is a little inductor that's used to boost the voltage and charge this capacitor which is for the power supply for all the circuitry and it does so via this diode. it's a little boost converter. Um, on the driver side for the piezoelectric disc, there is a Transformer notice the heavy winding here, the primary five turns and then the higher number turns a secondary and there's an inductor in series with that and then a big separate Reservoir capacitor trickle charge from the other side just to provide energy for the bursts that this poops out.

It's quite interesting. Now, the piezoelectric Disc: Not the nicest picture here, but it's okay. Uh has a stainless steel disc and in the middle, let's get a little sort of hump, a little dimple with perforations on it, and I Think when the liquid is placed up against it, the wick from the aroma liquid touches onto the surface and it creates a little well of the liquid in here, just by surface tension. And then when this pie is electric, disc vibrates at ultrasonic frequencies.

It basically atomizes that and creates the width of the vapor of the aroma liquid. the disc itself: One electrical connection of the donut shape disc is onto the back of the stainless steel disc and the other one has a conductive coating on this side and the wire is sorted on, but they also look as though they've run a little trace of solder around this just to beef it up and give it an electrical con continuity and also beef up the current. The whole structure of this, the wire assembly that holds it in place, and the little spring inside levels are off on top of that Wick and also just gives it enough play to move up and down as this is put in. It's all very clever.

It's really well designed. it's really nice. so let's take a look at the other side of the circuit board, which is the interesting bit. So I'll move those out the way and I shall Zoom down on this a little bit or maybe not that much.

That was maybe a bit excessive. There we go. That's better. First of all, an apology.

So for saying Mass dads about rubbing number off this chip they hand. it was just covered in flux so the number is underneath it. It is intact. It's a 3055l mosfet.

This however, is an Asic an application specific integrated circuit and that's all I can think it would be unless they've Incorporated two chips or it's a chip with a boost circuit for the voltage which I have come across before microcontrollers with a boost circuit but in this case I think that it is just a dedicated chip for the for this mass-produced product and uh, it has some Oddities There's a couple of resistors and a three capacitors connected on this that are probably for setting internal oscillator speeds. And then there's this uh, array of resistors. one two three four that are actually all in series. but they have solder Bridges so they can fine tune the value of that resistor, which may be to fine-tune batch by batch.

The frequency or drivers appears electric transducible. That's my guess. There's a little resistor here. the trickle charge is a big capacitor for the Transformer driving and then there's the mosfet Transformer little inductor here and then the piezoelectric device is across that let's take a look at the schematic to make more sense of this.

Anything else worth mentioning here, not really covered everything. Clever design, very neat I Think the person who designed this must have actually quite enjoyed it. Foreign. So here is the 1.5 Volt double ASL I Shall just write double A next to it and it creates a 1.5 volt.

Supply Which is enough to start part of this circuitry. And there's a 100 micro Henry inductor and the diode. So what this is doing? When it's powered up, this unit starts pulsing that when needed. It looks as though it has a regulator to detect 3.3 volts.

So it pulls this end of the inductor down to negative. And because that ends positive, when the inductor is then turned off, the polarity reverses as a magnetic field collapses. This anchors positive. That ends negative.

It adds on to the battery. but also because depending on the load, it will actually produce a higher voltage and it goes via. this diode charges up this capacitor until the chip detects that it is 3.3 volts. The taming is set by this Uh multi-position switch.

The middle connection is not used just the four out connections, but it can tell from that that you know the five different power level settings, the five different delays. There are three capacitors here now. I'm wondering I think one may be a time base for the circuitry, but another one maybe a Time base for the Uh piezoelectric transducer and the other one? Not sure what it is. Uh, hard to say because it is a application specific integrated circuit.

There is no data sheet in this that I know of Um, but these will probably be based on these will set times and also it could be the capacitor is providing. Uh, there's an internal power supply reference and it's using capacitor for that. For stability, there's that resistor array which probably is associated Within These capacitors and it is probably setting the frequency that this is driven with because it will be quite crucial. Uh, they'll be kind of matched and uh, it has to be correct for maximum efficiency and it may just vary between batches.

Initially I Thought they'd done it in a binary style like 2K 4K and well, it would have been good to be 1K but it's 2K 3.9 K 1.65 K and those ones can be bridged out. These two are bridged out to fine-tune the value. Quite unusual, this resistor slowly trickle charges this Big Fat 3 300 Megaforce 6.3 volt capacitor variable voltage and uh, I Think the reason it does that is just a safety thing because it keeps it isolated from the rest of the surgery for stability. But also if something was to go wrong, this transistor was to turn on continually.

It limits the risk of damage because only a certain amount of current that this capacitor would be discharged through this coil and through a transistor. But then this resistor would limit the current. so it might be a safety feature, but it also has an interesting effect of a sort of sort of ramp of the output of this. It starts off the high pulse and then reduces.

There is a little Transformer that steps a voltage up and then there's an inductor. 220 micro handwritten series with the piezoelectric donut that just atomizes the liquid. Now I can show you some waveforms. This thing drives the mosfet in 10 millisecond bursts, and those 10 millisecond bursts every eight seconds or more are a series of pulses.

Roughly kind of square wave, but kind of like it's not showing a square because the risk, capacitance involved and other things that affect and even the oscilloscope probes probably. but it appears to come up at around about 154 kilohertz. Um, and uh, that is presumably the frequency that the piers electric disc is being driven at, then the waste driven. Uh, what is this? That's the capacitor voltage drop during the burst.

So the capacitor charges up to the 3.3 volts, but with those bursts to actually progressively discharges it. But it doesn't go right down to zero. but it basically holds the energy to deliver those High current pulses before the for the duration of that uh, 10 millisecond burst. The let me get the next picture in next slide: capacitor Voltage.

Uh, actually shown with reference to zero. there's where it was turned on. So that is the zero point. and it basically the charge of the capacitor is such that it wrap, it goes up to the full 3.3 volts.

But each time that little 10 millisecond pulse happens, that's it happening in here. That tiny little glitch there. Then the capacitor charges back up again through that resistor, ready for the next one. and then the burst happens eight seconds later, and then it charges up again.

It takes a fair time to recover, but then you'd expect that. and just because of the nature of the size of the capacitor and that resistor is quite a nice approach. It makes it a safe I think that's more or less it. I've covered just about everything there is.

all the rest is in this mystery chip here, but it is unusual. quite fancy. maybe I wonder if I could use that to drive other transducers by changing the timing capacitors if they've basically left it fairly open-ended I'm not really sure, but that's it. So I played with these a lot when I was younger when they were available.

I mean to put things into perspective, the battery in this one was dated something like 2005, expired it, and so it's a while since they were out. Um, but I played about with them and, uh, inevitably wrecked them by putting the wrong liquids. and I think that liquid really matches I think it has to be a very pure, a very light oil or something like that. I'd have to test that.

It does say that it's flammable. so I'm gonna going to guess it is the oil because it certainly wouldn't be water-based if it was if it was flamble. Um, but yeah, I'm looking forward to experimenting this one putting liquids in now that I know what the circuitry isn't When I was young I found these tended to seem to stop working uh, but they weren't even clicking. but it's just they were very random about their operation.

Maybe that's why they're not available still. Uh, or maybe I was just misusing them which is also a possibility, but very interesting. Now I know the circuitry. it gives me a much greater understanding.

Makes me appreciate the work that went into these because uh, it is a very interesting design and it's a novel effect and it just the battery lasts so long for being able to just atomize tiny little portions of that strong Aroma It's very clever. Very neat indeed. The Glade wisp atomizer.