This is a little Gadget that was given to me by Vince the crew chief at work. It's a pouch that can pop up if you pull it like this and it's got a button on top and if I press that button you'll see it flashes red but doesn't really do anything. It's also got a micro USB charging port and if we take a look inside we can see that it's uh, ultraviolet sterilizer. It's got that sort of pop-up feature so you can get the LEDs presumably further away from your phone or whatever.

your sterilizing have never worked out why people would want to sterilize the phones this way, but it's got the two-year VC LEDs and it's got a little ribbon coming up here and it's a safety interlock because the only way it'll operate is if you pull the zip around and lay the magnet in the zip onto this little cover here and then when you press it, it will light up blue and it will flash to show it is sterilizing your device. However, as soon as I undo that, it goes off. but if I put my finger underneath to push the button and grab a convenient magnet to bypass that safety feature, you can push the button in. the little LED lights light up the little UVC lights.

It's notable these ones only of the UVC chip and not the visible chip as well as an indicator. So let's take this apart: I have a suitable screwdriver here. let's Zoom down a bit and I can see for a start that there's little plugs have been put over what I presume are screw holes? Are these going to come out easily one? Oh, they're not coming here easily. Well, I pause while I do this.

I will pause while I get these out. They're a bit fumblesome. One moment please. I have removed those sticky little plugs and now there's one screw left remaining to take out.

And this should reveal the dark secrets of this quackish medical sterilizer type device that belongs to the covered era when Abdi was like sterilizing everything. What is inside quite a large is that heatsink, please? That's not bad. That's quite interesting. There's the battery which unplugs.

Oh, there's a little ribbon cable that unplugs from the so. let's unplug the battery for a start, which does appear to have possibly charge monitoring because it's got three connections. Great. We've got a little ribbon cable here that I shall just I don't know if there's one that pops up.

Oh, it is the one that pops up and this is the circuit board. Okay, let's take a picture of this as usual and explore it further and see what makes this thing tick. One moment please. Reverse engineering is complete.

no small task, so let's explore. So starting from the left, we've got the button that activates the cycle. We've got two RGB LEDs the common positive and the red green blue chips are switched for your resistors and these transistors. We have the USB charge port, the classic 4056 charge chip.

We have a connector for the battery. the Lithium cell doesn't just have a protection built on, it's also got a 10K thermistor for monitoring's temperature and that is used. and we have a three volt voltage regulator called Seaux and we've got a microcontroller by East Soft never heard of that brand. Uh, we have a level shifter here.

We've got a transistor designed to switch on a peach on a mosfet and turn on the voltage boost circuitry and that boosts the voltage up and that's monitored by the microcontroller as opposed to being this device itself. That means the voltage that puts out can be set in software. We've got a hall effect sensor connect onto here and that is used to detect when the safety device the little magnet is in position. Anything else worth mentioning? It's a very thorough design.

Lots of capacitors like Banks of capacitors for uh, good filtering. It's actually a surprisingly good design. Let's take a look at the schematic. Anything else worth mentioning here? Not really.

There is actually something worth mentioning. The LEDs are run a fairly High current 200 milliamps with 6 volts each. and for that reason they have these large heatsink fins on them. this is to all intense properties, are a serious ultraviolet sterilization device.

There's also a little position for a programming Port here for programming things during manufacture, including that voltage which sets the current through the LEDs Let's take a look at the schematic. I shall Zoom down a bit onto this. Now the schematic has been divided into three sections because it's a monster. so let's get take a look at it in modules.

So here's the power Supply module. Here's a USB charge port uh, smooth and compatible, two smoothing capacitors a little written, a little two next to that, and the classic 4056 with a 3.3 K resistor. That's around about say 350 milliamps. The Lithium cell itself is Uh rated 516 milliamp hour.

It is a 50 30 40 which relates to the dimensions. So another capacitor on the output. there's a Lithium cell with its protection. It's got a built-in thermistor which is the third connection and that thermistor can be looked at by the microcontroller.

I've written CPU or should written MCU here, but that's fine. You don't know what I'm talking about, but the MCU can take this pin high and that then forms a potential divider and then it can read the result back. And the reason it only does it momentarily is so it doesn't waste current. Uh, going through those resistors all the time.

And after that, there's that oddly named Saux 3 volt. uh, Power Supply. The look of it. Um, and that has three capacitors in the output.

just provide a good, solid, stable three volt output. Anything else the processor can monitor for the end of charge from the charge end, or standby output from the 456 which pulls a low and that just indicates the processor that well. It can detect when the USB Supply is connected. that's not something I've drawn, Is it? That's something I missed here.

But there's a couple of resistors and the processor uses a divider across here. Let's draw them in. There's a USB connector. Here are two resistors and I should get the value of those should I and they are then providing two.

since I've not left much space. I'll jump over here. M C u I'm just going to get those values one moment, please. And continuing, the resistor values are 100K and 200k.

Nice round figures and they just provide a level to the CPU The microcontroller should you say the MCU that it can then use to actually detect that the USB supplies connected? That makes it go through its little I am charging thing and then it gets the charge and from this signal it will change the LED color to probably just static green I think to show it's charged. Anything else worth mentioning here? That is all the circuitry that I Think Hope. So we've got our V-bat which is the battery voltage and we've got the three volts. And we've got the zero volts.

Those are the three main Supply rails used, but there is another Supply rail. Let me elaborate on that two pages away. This is the quite complex boost circuitry. Let me just check.

this is actually recording I've done that before. So the microcontroller, when it wants to turn on the voltage Bridge circuitry to drive the LEDs uh turns on this transistor which pulls the mosfet gate down to the zero volt. Rail and if in doing so, turns on and that powers the whole voltage boost circuitry. But the microcontroller has control over enabling the Boost circuitry as well.

It's got a couple of air capacitors here for the smoothing. Um, the boost circuit I would expect would have a feedback input. It's got It's got an odd number on it I couldn't actually find Uh something directly. It says Efo so I'll just write up there E F o That didn't bring anything up and a quick search didn't immediately find things that were pin compatible.

However, this is a boost circuit with Uh switching output which pulls this Uh coil this inductor to the zero volt wheel via this one point Sim 4 ohm sent resistor and uh basically speaking, when it's running, it will build uh, put a magnetic field into this and then when the magnetic field collapses, it will produce quite a high voltage Spike which goes through this diode and charges up these capacitors and that provides the high voltage. The voltage is monitored by this divider 200k and 10K and I measured the voltage at 12.9 volts in use and that goes back to the microcontroller and then the microcontroller controls enable. Normally, this would be tied directly to these chips just so it provides a fixed voltage, but this lets them program the voltage and software. Um, the UVC LEDs have a 2.2 Ohm resistor in series and the voltage measured was 12.9 volts and the current I measured by measuring the voltage across this resistor was 200 milliamps.

These LEDs because they've got a very short wavelength, tend to have a very high voltage, so it's roughly 6 volts across each one. and that is that circuitry that took a lot of reverse engineering that took a lot of proving with the double-sided circuit board and bouncing tracks making that quite complex. Okay, final installment: The general display buttons, management and safety. Here's a microcontroller with its three volt rail.

There's the battery rail which is going to all the LEDs each. LED has its own 1K resistor and a transistor per color and then a 1K resistor to the base of the transistors. The use of 1K throughout is just because it's a nice standard value. They're very popular if you ever have a collection of resistors for your own projects values like 101k 10K All that of the decimal values is quite useful.

The hall effect sensor is for safety. It will only let you use this unit when the little magnet in here is brought round the zippers all the way around and then you lay it onto this area here and it sticks slightly. but it's also activates a little electronic hall effect sensor. That whole effect sensor is perfect in three volt rail, very low standby current.

It's got 200k pull-up resistor and and that means that when you actually close that zip into position, that this rail is pulled to the zero volt rail. This input to the microcontroller and it knows that the switch is in the safety position and can light the LEDs up to show that everything's bred to go. You push the button and and it starts the sterilizing cycle so it is a very complex unit there. I Shall not go too far out here, but that's took a lot of reverse engineering.

It's a complex unit and it's nice that it telescopes because that does mean that it's actually oh yeah, and that comes off. It does mean that uh, it gets much further away with the ultraviolet UVC LEDs from the object you're sterilizing, which means it's getting a better coverage. um I Don't know if I mentioned it's got the USB charge port under. here.

it's got a little button there. These are all falling out at the moment because uh I've taken the screws out, but it's uh, not just getting them a decent distance from the device being sterilized, but it's also, um, putting very high output. It's not just like just using cheap LEDs and running them at just like 30 40 milliamps. it's actually putting 200 milliamps through them which is a decent uh amount of UVC So it seems it's probably one of the most serious ones I've seen so far.

They're very interesting, very neatly made. but there we have it. The HoMedic was that? where's the text on it I don't see text I may have removed the text accidentally I thought there was a level in this. Oh, it is.

It's got it on here. Um, yes, the Home Medics um UV sterilization device. It might be useful for some applications because it has been seriously designed.