Hi welcome to the ever popular mail bag segment where I open my mail I Got four items today uh, two which look, uh, like they're from the same person. one little padded envelope and one cardboard box. Let's get to it. and if you want to send me stuff, send it to that crazy Aussie bloke PO Box 7949 Borham Hills BC New South Wales 21 53 Australia not Austria and uh, these two, uh, similar packages I got they come from China it's got the uh traditional Chinese uh custom form on the back contents.

what is it? No idea, can't read that, but uh, there's no uh, address or name or anything like that. So I have no idea who actually sent this, but thank you very much So let's rip it open. It's got a uh, it's got a regular uh padded bag here so let's just don't need the knife for this. Can just rip it open and what do we got? Oh nothing else in there I've got what on Earth Is this? It's like a Is it a bag? No, it's a Are you kidding me? This looks like a ladies oh no I Hang on.

this is ridiculous I don't know what they're uh, what they were thinking when they sent this, but it looks like it's a ladies uh I'm going to have to even put it back further. it's looks like it's is it for is it for Ms Eev blog. It's certainly not for me. It's a little I don't even know the name for that.

It's like a little black mini skirt. dressy kind of I don't yeah I have lingerie kind of stuff I Have no idea. Haven't got a clue. Oh and and there a G.

Okay, it's lingerie. There's a there's a G string folks and uh, that no is not a thong. No you Yanks have it wrong. Thongs are what you wear on your feet.

This is a G string, not a thong. so that's for Mrs Eev blog for Mr Eev blogs Enjoyment: I'm sure. thank you very much. Whoever the anonymous person who sent me that, that's my first non-electronic item.

Hilarious! Now I don't know about you, but I'm a bit nervous to open this uh, second one here, which is obviously from the same person. um, cuz it's the same style of packaging comes from. Hong Kong they didn't didn't come at the same time. they came a little bit apart.

but gee, I don't know Now I'm concerned it's quite. It's quite heavy. It's quite big, so once again, there's no other info in there. So I don't know who has sent this.

but let's uh, try and hack into the bubble wrap here. No. I'm really concerned I have no idea what this is. It's a lot of bubble wrap.

It's a lot of bubble wrap. What is it? A look? Oh, it's a watch. Beautiful. There's a multimeter.

Oh, it's a bonanza. It's a bananza. We got digital calipers, a watch. Let's have it.

hang on. H We've got a scale. Little one of these little micro scales. Brilliant.

5 kilos * 1 G Brilliant. Definitely use those in the lab here. Digital caliper operating instructions. This is all the finest stuff that China has to offer.

Brilliant. And I've got a cheap ass $2 multimeter. Oh yes, doesn't get any better than that for your cheap ass $2 multimeter. Woohoo! that'll work a treat.

So I can definitely use this sucker as a sacrificial meter in I Don't know. Blow the out of it. can drop it. Oh, possibilities are endless.

and as always with one of these one hung low brand meters, something doesn't work. In this case, the backlight. Complete fail. But let's have a look at this watch.

Oh, feels feels really really cheap. Let's uh, see if we can have a look at this. it's a TV DVD remote control watch a TV 12. whatever that is, it's a touch panel watch.

Oh oh, look at that. It's just got one dodgy LED in the corner there. so it's sort of. They're trying to light up the entire screen by one corner and it's just a fail.

Really? I Mean, at least you have a couple, but you've just got this huge bright spot and this is like the cheapest quality watch you can it? Just it makes your skin crawl. Really. You can barely see the font on these little buttons. that one says light I wonder if it.

uh yeah, it light. And then there set. there's mode presumably. Oh, it beeps too.

It's got a stopwatch, whatever that is I don't know. No idea. It's only got a couple of modes. Go come at.

TV DVD So I don't know? No idea there. What's that like? They up down buttons set. Yeah, terribly exciting stuff. And there is the a little uh, infrared LED on the top.

What is that? an Lkm? Ikm I presume that's an L with a big, you know, underline kind of thing. Lkm TV2 cheap I'm sure they churn these out for about 50s and that uh LCD really is hard to use except anything face on and slightly down. if you're try and go slightly up. trust me, that's not the camera that is actually Vanishing I can't read that as well.

That's just. you know it's not a great LCD as you'd expect in these really cheap one hung low brand. uh, you know. Absolutely churned out at the cheapest possible price.

Put the minimum amount of design effort into them and it's got four. uh, is that are they even buttons? No, they're not buttons on the side. They look like buttons. They've made them look like big Press buttons.

But they've done a touchscreen watch like you know? Yeah, Why really? I Don't see the point. Just put proper buttons on the side. Fail. And if you get this screen at just the right angle, you can see the touch panel.

You can see the line on the touch panel. like that. So they've got three columns down like that. you can see the break in the break in the column there and down there.

I'm pretty sure you can and it then got goes across there like that. so there's three parts to it. that one, that one and that one by the looks of it and you can just get that at the right angle. You can see that from quite a few angles.

It's actually rather distracting and that comes up a lot. and it sort of eats into the clarity of the display. So it's really, you know, a poor choice to go for a touch panel. Uh, display like this When you can just put buttons instead of putting fake buttons on here.

Give me a break. Come on to make it look like a real watch. Oh, put fake buttons. But we put a touch panel to make it all funky.

Then we'll put a backlight and we'll goof that as well by just having you know, not a nice even. LED backlight. With you know, the lights coming in the side and the light pipe and the whole thing evenly lighting up. Or even an E backlight or something like that.

No, they got to goof it by just having one LED in the corner like that. Unbelievable. Now, unfortunately these digital calipers. that screen looks like it's been smashed.

Oh it has. Oh what a bummer. That's yeah. there's bits of glass, shattered glass everywhere.

That's a shame. That's a nice big readable. LCD Otherwise, much bigger than the one I've currently got. Does it still? uh oh.

there's a bit of a that's really crusty operation there. but uh, if I zero that out, it's I think it's got all glass caught in the sliding mechanism. Yeah, it doesn't quite go back to zero as almost. but uh yeah, that's I Think it needs a good clean up, but uh, thank you very much, that's going to be very handy indeed.

Have a uh second one I don't actually have one at home, so uh, I might clean up the LCD glass on that I'm going to have to scrape it all out. it'll still operate without the glass of course. and uh, try and clean the mechanism up. Give it a bit of a Lube or something like that and it should should work.

Just a treat. And the interesting thing about these calipers is that most of them and this one does. By the looks of it, it's got one of these data ports in there. You can see the pads directly on the PCB Um, and don't quote me.

I don't exactly remember, but it is like a um evil like a it's it's some s of Serial um output. Whether it's sort of like a uart rs232 type compatible. whether it's a SPI I can't exactly remember I'd have to look that up. but um yeah, apparently you can, uh, get the data out of these very easily and interface them to a microcontroller and uh, use them for all sorts of, um, weird and wonderful projects because these the the sliding, the uh, the mechanism used to detect, um, the absolute position of these things is, you know, extremely accurate.

So these things can be very, very useful to uh hack into and Ed for other projects. So maybe I'll use this as an experimental um hack one. maybe cuz these are quite, uh, cheap These days you know you can pick them up I I can remember back when you know a pair of digital calipers you know was gez cost you a week's wages or something like that and uh, but these days you know I don't know what you pick them up for probably in China you pick them up for five or 10 bucks tops. something like that.

So they've mass produced these things. But anyway, thank you very much. And for the lingerie. Brilliant! And here's the scale.

It does a really dodgy, uh quality. LCD display there got a horrible uh, viewing angle and stuff like that. It's really quite washed out. but I don't know assuming it's accurate.

what is my uh, there we go? 45 45 G it's 1 G resolution of course. up to uh, five kilos for just this little plate. That's a lot. but uh, there you go.

45 G for my Swiss army knife Victorinox um mini champ there and of course not legal for trade. Brilliant! So thank you very much to the anonymous person who sent me all that stuff. If you want to remain anonymous, that's just fine and dandy. Thank you for the Uh selection of a finely crafted and finely engineered Uh products that China has to offer.

svane if I'm pronouncing that correctly. svane minut from whatever Sa is that what? it probably not. uh from Belgium Anyway, um, hello to all my Belgium viewers and uh, no stamps. They've just got the uh, the old printed thing on there.

Pretty boring I'm afraid. but uh, there you go anyway. Let's uh, crack this one open and see what we get inside here. Belgium what do we got? Little anti static bag and a note I do like notes: Let's have a look see linear I assume that's linear technology Yep.

Application note 47 figure D1 for the schematic: a PCB the PCB design is mine. uh I'll post a link in the Forum oh Forum user thank you very much. Um I have a few black PCB left over for anyone interested. Excellent! So there you go.

Um, you TNT on the Forum Hopefully we'll see the result on a 1 gz 300X Oh oh I think I know what this might might be without even looking at the app. Note: I'm thinking this is possibly one of these fast rise time kits I've been meaning to build one I'm only guessing I hope I'm not wrong because that would be really cool if it is a fast one of these. um, you know it generates a fast rise time. uh pulse to uh yeah, oh it's even.

oh it's it's already built up and I think it is I'm pretty sure this is what it is. Brilliant I was going to build one. so it's a fast rise time pulse generator and what these are useful for is, um, checking the bandwidth of a scope or other things where you need a very fast, sharp, uh, rise time to generate. uh, you know.

Well there it is. Hey Pulse Generator man Man s Thank you very much man. this is Awesome version 1.0 um 2002 30th uh uh, 30th day fourth month so it's pretty uh, recent and uh, he's he's got. he's marked it there.

1 Point what's that? 1.5 volts is it plus minus I'm not sure I have to look at the app, note and things but the pulse generator. you put it straight into the scope. You can't have a lead of course because any lead has inductance um in it. even the PCB traces.

You got to lay it out properly and uh cuz otherwise that can affect the um. the rise timing gives you overshoot and undershoot on your waveform. There's a bit of an art to uh designing these. a very sharp rise time Edge Um so this is probably like 350 Picos seconds? maybe? I Think uh is sort of one of these standard one and it's all dependent upon the transistor.

It uses a 2N 23 369 and they're not all equivalent apparently. Um, you've got to select on test for these things to find the best one, but that's a nicely little laid out board. Um, so we've got to put a uh Supply on there. A shame it.

you know it doesn't have like a battery holder on the bottom or something like there a AAA single AAA battery holder. but yeah, um it'll have a step up uh converter of course. and uh, to step up the 1.5 Vols because it uses the Avalanche brake down of the Uh transistor here to generate the pulse. So um, it read all about it in the Uh application linear technology application note.

but I'm definitely going to try this out. As big Kev said I'm excited and what I really like here is the BNC You can see how it's actually purpose designed for this. It's actually cut into, it's got a slot cutout in there. It's designed to mount on right angles on a PCB like this and it looks really rigid cuz it locks the board into that slot there.

I Really really like this B andc connector cuz it Doesn't you know it's not going to flex at all cuz that board is totally locked in that position and of course you got the huge big solder tabs here. and of course for your utmost in that signal Integrity you've got your surface mount pad on here cuz you don't want to have a through hole uh, lead cuz that will just add to your inductance so that's a brilliant choice for a connector. I man I was actually I really was going to design one of these little uh puppies and maybe even, uh, sell it as a kit or something like that. but I'm not sure if I'll bother any more because Minut has, uh, done all that for us.

Look at all the Vas too. He's stitched all the way along there for the utmost in uh, signal integrity and high frequency performance all the way around. There just stitched it complete the top and bottom plane. Very nicely done.

Nice little compact layout I Like it. but I just realized something with this. Of course it's um, the socket type instead of the plug type. So we're going to have to use a BNC to BNC cable to go in.

Um, it would have been nicer if it used the Uh type which can plug directly into the front panel of this scope. That would have been much better so that was really easy fixed. I Just solded a single AAA battery holder on there. You could sort of mount it on the back.

You could glue it in place or tape it down or uh, something like that and shorten up the you know, shorten and tidy up the wires. and then you can just stick the AAA cell on the back. but uh I won't I'll do that. Nice.

It is later, but let's plug it in the scope, see what we get. And we got lucky last here and it's from Wittenberg in Broken Arrow Okay, I assume that's Oklahoma I think in the United States of America um Wittenberg I assume is their last name I guess Um, so that's let's have a look on the back here. What does it say? It says it's a soldering kit worth a whopping six bucks. So let's take a look at what type of soldering kit this is.

Wittenberg Thank you very much I Assume it's your apologies if that is actually your first name. but let's uh, tape of course. Tape Boom! Gone Gone Taada Here we go. What do we got? Oh, here we go.

A nice looking board in here and that's it. Oh, let's check it out. What do we got? Hey postcard. Brilliant! Tulsa In greetings from Yeah I was right.

Greetings from Oklahoma Enclos in my EV blog: Inspire Constant Current dummy load Brilliant. He's seen my video every man and his dogs making a constant current dummy load. There's tons of them, tons of people making them on the EV blog. Forum Check them out! Some really great um, schematics and info and uh, photos of people's builds of their constant current.

Dummy load. Some are building like big, you know, kilowatt dummy loads. Awesome. Anyway, it's Open Source Hardware You can download Gerbers bomb and schematic from my website Sleepy Robot.com That is a brilliant URL I Love it so go on check it out Sleepy Robot.com You know you want to with a name like that.

um I Also have a few kits available so by all means buy one! Chris Wittenberg thank you very much! Chris from Broken Arrow Beautiful name I Love it and uh Tulsa Oklahoma first Incorporated in 1898, Tulsa was also considered the oil capital of the world M and also has played an important part in the nation's development of Aviation the Space Program and National Defense Fence. Excellent hello to all my viewers from Oklahoma and from in particular Tulsa And it's pretty much exactly the same as uh, my schematic. He's got a coarse and fine potentiometer here mixing the two obviously didn't uh, wasn't designed for a 10 turn pot there got a voltage fer which is a microchip mCP 64 and then pretty much the ident almost identical uh circuit to mine. got a little, got a voltage divider there with a little uh filter and uh basically he's got he's using the MTP 305 n Channel mosfet which is one of the ones I use cuz I had in my parts bin he's uh got the resistor on the output there so driving the capacitive uh gate doesn't cause the uh Op amp to oscillate and and got a bit of capacitive feedback here to stabilize it and that's about it.

And he's using 2, 4, 6, 8, 10. There we go: 10 10 ohm resistors a 1 ohm load like that. Got a basic heat sink and a voltage regulator 78 l05 and it's tied off the Op amps here so they don't oscillate and it's got an LED So pretty much um, very similar circuit to my absolute Bare Bones basic one I showed in one of my earlier videos and here's the exciting part. Let's take it all out and ni see it's got the yeah, it's got the same uses the same heat sink as mine.

Brilliant. This will actually be uh much nicer the My one which is pretty bodged if you've seen it. mine was, you know, pretty bodged thing and there it is. constant Curr current dummy load.

It's a open source and it's got the headsink on there. Nice battery holder on there 9vt battery holder. brilliant and uh, course, just course and fine adjustments. You could of course replace that with one 10 turn pot if you really wanted to.

ah look at that Tulsa Oh I Love the I Love customized uh you know little silk screens like that Tulsa Tulsa is that Tulsa man Tulsa man from Oklahoma and unfortunately I got a race off home so I don't have time to build that up now, but I most certainly will cuz I Want a neater, constant current dummy load? That's fantastic, so thank you much! Chris Wittenberg from Sleepy Robot.com Check it out! So thanks for all of the people who sent stuff in for today's mail bag. It's brilliant and the address was at the start of the video. If you want to send stuff to that crazy Aussie blog, please do. And if you like the uh, mailbag segment, don't forget to give it a big thumbs up.

Catch you next time.