A poundland winter beanie with led lights, supposed to be a summer beanie as well. Do you call them beanies, where you are they're called beanies here, just a woolly hat very popular, particularly on an island like isle of man, especially leds, because you need led lights when you're nail of man, because it's a very dark place, but this cost five pounds Or six six euros um, and it is usb rechargeable now to save time, i'm going to pop this out. It's worth mentioning it can pop out. If you hold the little frame at the side and you squeeze the middle it pops out, let us explore it in greater detail uh, when this arrived at the little dab of glue in it to hold it in place.

I think that might have just been for shipping because it means you can wash this hat without uh worrying about damaging this. So you've got one button and it goes through high intensity, medium intensity. You can see the pulse of modulation, let's zoom down this, because that's probably a good idea and it's got low intensity with even more visible positive majority pulse with modulation, and then it goes into strobe mode, where it's it's just a slow strobe. It's worth mentioning a couple of things: if you press and hold it for a long period of time, it does not go into sos mode, which is good, but also, even if you have on say full intensity for several minutes.

It doesn't seem to do that thing that some do that one press actually turns off. You have to click through all the modes. If you want to charge it, you pull this little thing off and it reveals the side, the circuit board, which is quite nice, and if you then plug it into a usb power supply. Actually you know what let's uh, let's get a charge monitor here.

Where is a charge monitor, i'm pretty sure i had to charge a monitor. Handy apparently not right. Just give me one moment i'll find a little charge monitor. I have found my rue dang charge monitor.

I shall plug this in at the little red led lights. It shows a current about 200 milliamps uh. Usually they charge the cells in these at the well, i'm not sure what size the cell is going to be, but they often charge it at the 1c, which is the capacity of the cell. So it might be a 200 million power cell, not really sure.

Maybe it's also fully charged and the current's gone down. It's not a terribly big thing right. I should put that out the way and we shall open this. You can see a pan on the back.

Well, that panel's all screwing through to the front does the front come off. Yes, it does circuit board. Actually i thought the circuit board was the same circuit boards going out there, but it's not there's the lithium cell. Let's explore it's got no markings on it.

Okay, it doesn't look terribly big and i would actually rate that round about 200 milliamp hour, and i tell you what i shall take a note i'll take a picture of this and then we can explore the circuit board. One moment please and resume: the reverse engineering has been done. It's a very straightforward design, nothing really radical! Let's just get a little bit closer to this, so you can see the layout the usb supply comes on when you're charging it and it goes via this diode. The negative is common throughout the whole circuitry, but the positive goes via the schottky diode uh to the charge, control chip, which is a 57bm.

It's just a generic 4057 type charge control chip and it has a couple of decoupling, capacitors and also a 5.1 k resistor, which sets the charge current for the lithium cell that connects here. That's going to give a charge current of up to about 250 milliamps the led control. Oh, the other thing it's got is a couple of leds here with a common resistor, that's a little bit of an auditing where they've taken the resistor from, but it's a 680 ohm resistor and then a red led for charging and a green led for charge. That's all done through this little charge control chip.

The flashing is done with this chip over here, which uses four pins. It's called a 2105, it's one of those generic. You know you won't you're not going to find anything if you search for 2105, but it's the sort of thing you'd find in head torches flashlights stuff like that, and i think it can drive leds directly by pulling to this zero volt rail. But in this instance, because it's driving for quite chunky leds uh it's using an a1shb mosfet to beef, that of current up a bit.

And then it's got a couple of 15 ohm resistors and series with each pair of leds um, which then sort of limits. The current through them, i have got the lithium cell on charge at the moment at the moment, it's looking to be around about 200 milliamp hour or just under that. I shall let you know i'll, let you know in the description, because i i shall know by the time i finished recording this video. Actually, i probably won't it's still charging right now.

Let me show you the schematic, so i'll zoom in a bit further on this. Here is the schematic and i've added lots of little random notes at the bottom here. I'll explain those later on. So here's the usb command and it goes via that shortcut diode to the 405 7 charge control chip.

The shortcut diode is useful for two reasons: it protects against reverse polarity, but it also drops a little bit of voltage and that's useful, because this uh chip here is a little tiny, six pin chip and it dissipates any difference between the five volts and the battery Voltage the lithium cell voltage as heat when it's charging, not that it's really an issue at the low current that it's using. However, that diode will actually drop the voltage slightly and it'll shear. It will dissipate a little bit of heat, but it will just take a bit the strain off this chip. Here are the two decoupling capacitors either side, which are just the standard part of that recommended design, which is good.

They include them normally, the 680 ohm resistor would be taken from the same supply rail as this, but they've taken it from the other side, the diode, which is the odd bit. I don't think it really matters that much, but it then goes that 680 ohm resistor gives a positive supply to the current limited supply to the charge and the fuel leds, and then they just go to the pins on this chip. There's the resistor that sets the charge current and there's the lithium cell. There is no over discharge protection for the lithium cell, but by the time, well i'll explain that afterwards, the by the time the voltage gets so low.

The leds are quite dim uh. It's still within a safe level of charge. Here's a little flasher chip which has the positive connection, negative connection and a push button that connects to negative its output. I presume it could theoretically have leds connected directly to resistors, but in this case it pulls low to turn things on so they've used the classic a1shbp channel mosfet, which is connected to the positive rail, and let's call that just positive, positive and uh.

The a1shb connects the positive rail and, when its gate is pulled negative, that's when it turns on so at the moment. Normally, it's kept off by that 10k resistor pulling up to the positive rail when the chip does turn that, on it powers, the four leds with two 15 ohm resistors at one resistor per two leds. I measured the current by hot wiring it with my bench meter. Um i measured the current at full power high level setting 173 milliamps mid medium setting was 85 milliamps low was 42 milliamps, so that's pretty much uh half and quarter the main output and the flashing quite hard, because it was a a 50 50 ratio, but really Slow, so i'm guessing that it's the fuel current under 73 milliamps, but because it's on half the time it'll be 85 milliamp.

When the battery drops to half voltage, the full setting the high setting, which was 172 milliamps, will go down to 115 milliamps and way down. When the battery is reaching the point, it should really you should stop discharging it. The current has dropped to 10 milliamps at 2.7 volts. So this is one of these things that it's not going to cut off.

It's not going to plunge you into the dark. It's great when the batteries run out, it's just going to get dimmer and dimmer and you're going to end up having to take off and like hold up to things to be able to see them. But it's not going to just basically desert you and just plunge into the black um, so that is quite good actually and by the time it gets down there you'll see it's dim and you'll want to put it in charge, so win-win it's not really going to Over discharge, the lithium so much um, but that is it not really much else to say. Oh yes, there is the charging circuit board is two millimeters thick, which is very similar to these little plug-in leds, it's a bit thinner than it should be.

I think for the usb ports, because it's a bit wobbly, but it does still make connection they've, really gone to town the pads here, the tracks uh for making that connection. It works quite well. I tried in a few connectors and wobbled it and it still made a good connection. So it's low current, it's only about 200 to 250 milliamps anyway, so it doesn't really matter that much.

It's giving me inspiration this reckless approach to two little usb plug-in circuit boards. I've thought about that for a while um they've taken a much cheaper option than this, but you know that looks good to me because i'm trash, but there we go the poundland usb rechargeable beanie, it's a fairly logical design, there's no real great surprises in it. The only surprise was the way they're actually using the circuit board, sticking out the side with this uh cover over it just to make a fairly neat arrangement, but i'm a bit surprised. I was expecting this to be just an extension of the circuit board inside.

I was almost disappointed. I found it as a separate circuit board, but that's still, okay, it's just a very cheap way of implementing a connector, and in that way it's a bit inspirational. It gives you ideas and like makes you want to explore things, but that is it. I think i've covered everything i have covered everything haven't.

I there's not much to cover it's a textbook design.