Hi, You know, the only thing better than a nice watch and that's a nice calculator watch. Look at this classic from 1983. the Casio TC 500. Trust me, it does actually say TC 500 up there.

Well, it did, but it's been rubbed off. Oh, look at this gorgeous classic watch. but you might think Oh Dave Where's the calculator? I Only see the four functions down there. Well, let me show you.

Ah, look at this. Bobby Dazzler It's on screen. This is a touchscreen calculator from 1983. This thing.

What's the Ducks guts back in 1983? Of course it's still not a patch on the best calculator what you ever made apart from my own micro watch. Of course the Casio is CFX 400 because it was a scientific calculator. This one is unfortunately only a four banger, but four function calculator Calma four banger in the trade. But hey, it makes up for it with being touchscreen.

This is unbelievable times. Blaire Blaire Blaire equals oh ah, thing of beauty is a joy forever. look at that. Bobby Dazzler This uses what's called the Casio Crystal Touch detection system or CTD yes for those playing along at home and it's got the electrodes actually etched into the top glass surface on here.

full function watch. So it's got alarm. this like calculator. It's got the alarm.

It's got dual time zone. It's got a timer and a chronograph as well. Fantastic. And it's got a light.

Wow Let's check that out. Hang on, look at that and grain of wheat bulb on the side. Classic. Now this.

LED rubbish. There is one silly design oversight on this. I've got the lights off for a reason because if you press the combine cancel button, book it. lights up the the bulb every time so it's taking a little gulp of current every time you do that.

and that's the same thing in. like the stopwatch. for example, when you want to laughs, it's like come on, it's hardwired to the bulb. don't and it really is just a beautiful slim watch as well.

Look at I Do not have a big wrist at all and you can see it maybe in comparison to my below. Accutron - here you can see the physical size of that. So yeah, it really is a nice small compact watch. Looks absolutely fantastic.

It's got the classic guy Casio band on it and the classic adjustable clip clasp like this, so it's absolutely terrific for those who absolutely must see the back side. there we go: TC 500 Stainless steel, back, water-resistant of course, and it's got a chrome plated polymer case on here, plastic bezel around the top, a quartz crystal glass top on it as I said, with the electrodes actually embedded in there for the touch sensing. Okay, watch, say this point here. When I turn on the calculator, you'll notice that these are segments.

Nice and solid. They actually overlay some of the other segments. Sometimes they don't like up here, but other times they do. So obviously this can't be on the same glass surface so they've obviously got like a multiple layers in there.

But regardless of the angle that I get this out, I cannot see a difference in the layers when I actually switch in there. So yeah, not sure how they're doing that, but it's very impressive. So we've got the recessed adjuster button so you don't accidentally hit it cause mode button to go through the different modes buttons on this side 12 24 hour format, but that also doubles as the back key for the calculator there and the light button. but in calculator mode, it's the Clear button.

As I said, unfortunately, it is only a for functional four-banger calculator and it's only got the eight digits. so if we actually multiply two large numbers, it'll give us an error. There we go, we've got an E up there and the C will actually clear the error like that. and then if we actually do that, the backspace will actually go back to the last number and we can erase that that was.

It's pretty advanced for 1983. All the best stuffs made in Japan For those you want to see this crispness on the LCD Just beautiful. I Don't know why they call it touch since a cow like it's a calendar. It's like they could have put the extra see on their touch since a Calc, thank you very much.

It's a shame that on this particular model the tea is rubbed off, you can just see the remnants of it up there and it really is difficult to see the embedded traces on this. And if I get the light shining on this at just the right angle, you'll start to see it. There you go, you can see the grids in their day and that strip going across. There is probably some zipper strip or something contacting that top glass surface so you can see.

You can count the number one: 14, 15, 16. That makes sense, you know. so you can kind of see the pattern. You can see them coming off the side and going around like that.

It's 16 lines buggering off the top there. It's hard to see the complete edged thing on here. Yep. I Think you can see a pad around the keys? there? You see that bit of dark darkness in there? Yep, so that's how they're getting the touch on each one.

So there's very little gap. Tiny little gap between each one there. Yeah, you can definitely see that. you really have to struggle to see the etched sensor traces on top of that glass like you just can't see it with the eye.

Anyway, I Think that is an absolutely gorgeous watch and if you don't agree, there's something wrong with you because that is just sex on a stick. So let's open this puppy up. See what's inside? Won't see a huge amount. Very typical 1980s construction, except we might get some sort of Zee strip elastomeric contact through to the edge glass surface.

just like an LCD So yeah. I'm not sure how anyone with large digits would have no pun intended would have actually used this because I actually miss these buttons quite often. so that's why they got the back key to allow you to go back and fix mistakes rather than typing in the whole thing again. But yeah, I've I don't have big fingers at all, so I can imagine larger fingers just would not work.

And in case you're wondering, um, no, you really do like there's nothing my little plastic poker there. My metal poker does absolutely nothing. You really do have to have your finger on there and get the capacitive touch. and if I even extend my finger out like that I can't do it.

It really does need your finger on there, but it really doesn't miss a beat. and they've sort of like almost perfectly calibrated the things so that you do actually have to touch it just at the right amount. although this will vary with you know, humidity and all sorts of stuff. and the manual actually you know warns you about scratching the glass surface and things like that because the sensor pads and and you know things like that and it will actually vary with environmental circumstances and any liquid or moisture on the screen that can affect it and stuff like that but like it just seems beautifully calibrated for a finger touch.

it doesn't like if I put my finger just lightly on there. it just makes it I Really do have to give it a little little tiny tap to actually get it to sense. Its borderline perfect. So we have to get the band off before we can then get in there so we'll pop that bad boy off and haha we're in like Flynn like I say classic Casio or any watch construction of the diet.

and if we pop out our coin cell there little see our 16 16, 4u, 16 16 fanboys made in Japan genuine Mac cell that almost looks like there's some flat flex construction on the back of that. and then we've got the classic plastic retainer clip like this and looks like we have out that's our waterproof or water-resistant seal. I'm because it's not actually waterproof and that's not knowing. it's just like a plastic dirty thing is that it really crapped out.

Oh ring I Think of my god, it's almost like turned to plastic. Not sure what the deal is there Anyway, not too impressed by that. Yeah, crusty as Wow that's classic watch construction. Of course there's our piezo transducer on the back, so the plastic retaining clip just keeps in the rest of the mechanism so we'll lift that out.

Oh no, we've got another ring and the thing about the metal back in here is they actually use that too. so when you push the button, the little contact in there pushes the metal against two contacts on the edge of the PCB usually yeah modules gonna pop out. We've got our little trimmer down there and a little reset and there we have it. The module comes out and today there is your zebra strip a little less turmeric connector on there which connects through to the contacts on the glass, service and the piece of if we flip that over we'll see yep, down the contacts on there.

So that's the only contact surface on the thing, hence why we saw all of the traces actually snaking their way down here and then right off and there you go. You can really see the contacts now. They are fantastic. I Mean you know, like touch technology? You take it for granted now, but like yeah, it's embedded in microcontrollers these days.

we can get dedicated, you know, at Mill Touch chips and other brand touch chips. But yeah, like back in the day this would have been like state-of-the-art stuff. Really, it's going to be a single chip solution. There you go, you can see the contacts on the side there which then connect between the top metal plate up there and the side when you push in the button.

So that's how the buttons work. Very typical. You can see how the contacts work right here when you push in the side. like this, it contacts the gold castellated edge, the gold-plated edge on the PCB down in there.

and that's what. So the metal backing, of course, is like ground or whatnot and that makes it and that makes contact with the gold plated edge of the PCB. And that's very typical in watch construction. You can see the contacts down in there for the zipper strip.

Maybe you can see the contacts on the zebra strip down in there. perhaps should be able to. They're tiny. There's lots of them.

There's more than what's actually on the than contacts that are on the PCB and the glass surface. That's how they make you know you have multiple connections through so you don't just have the one. And check this out at great risk to management. I have taken apart the plastic back holder.

There's nothing terribly interesting on there, but there you go. Look at this. This is like this is black magic from 1983 with a little slot 23 down there on the board. that'd be like an O 6.

No, that's a No. 8:05 actually. And there's our watch crystal up there. there little compensator trimmer cap, another cap.

there'd be a black blob under there, of course. And there's our contacts over there. And we've got these larger things here which I think are probably embedded resistors are. they would be my guess.

Looks like looks like they got some carbon resistors on the flim bedded on the flat flex. And of course that makes sense for a touch sensor based system so that they can. Of course they do it the capacitive touch based on timing. So to have the series resistor in there they can you know paneer, count pulses and do whatever.

do their time stuff but you know like to get this sort of stuff working. a 32 Kilohertz back in 1983 is absolutely remarkable. and the engineering that's gone into this is phenomenal. And I believe the retail price for this puppy back in 1983 was $29.99 so you know, Fantastic! And this wasn't the only casio model to actually have the touch they had other like you know, database and other type watches in there.

but wow isn't that sex on a stick? So it's interesting to look at the design decision here because they went well. We need a series resistor to get the RC time constant for the capacitive because it's just a resistor and the capacitor which is your finger then go into ground which is the watch case crown which is why the instructions actually tell you if you're operating on a table you have to actually touch the watch band which is then going going through two circuit ground. So basically you've got a series resistor then going through your finger, getting capacitively to ground, forming that capacitor there. There's already a capacitance there, but your finger just amplifies the capacitance.

Just it causes a greater amount of capacitance so it's just an RC time constant thing and they where well we need. We've got sixteen buttons. We need sixteen series resistors and that's going to be a bugger to fit those on the PCB I Mean you know we don't go to it like a four layer PCB or any of that rubbish. Jeez, and I hoped I Want to spare no expense on this thing? This is a cheap-ass consumer watch, so let's just put it on a flat flex as a resistive our substrate and I've done a video on carbon printed resistors on PCBs but it's exactly the same thing on a flex, so I'll link that at the end because it's fascinating how they do that.

but obviously they designed these onto the Flex. It meant that they could bring it from one side of the PCB to the other as you can see and then. so not only is it a routing issues, surface component issue, all that sort of stuff. bring it out to the zebra strip and go up to the top contacts.

Brilliant. So to design all of that you know all the metalwork and the custom plastics and everything like. Take for granted all your 3d designed for manufacturing integration and stuff. These days you know you can model all this in, you know.

Altium If you wanted to, for example, model your PCB and import all your step models for all your stuff done in SolidWorks or whatever CAD package you use and then you can fit it all together and make sure it all works and will use your favorite CAD package or whatnot. But to design that in 1983, designer manufacture that in 1983. That's just yeah. Hats off to Casio They're just brilliant.

but of course this wasn't you know. Exclusive LoCascio all pioneering watch manufacturers back in the day. Just you know, remarkable what they were able to do with their limited design tools back then. I Mean you know it'd be hard enough these days to actually you know design and manufacture this line back in 1983 early 80s.

Unbelievable. Now tell you what, It's not easy getting these things back in. The tolerances are ridiculously tight on these, so fingers crossed. It works.

That doesn't look promising, does it? I'll try the all-clear button again. and a little pro tip because that AC pad is recessed all the way down in there and you have to short it out to the case ground. Here you still the spring from the piezo buzzer. There it is.

Just steal it from there, whack it in there. but be careful it doesn't spring anywhere. and then you can short it out with a pair of tweezers or just bend it over. That's how you get it going again cuz these things usually need they don't have a power on.

reset Today we're back. Yes, we're no winner. Chicken dinner. Absolutely fantastic.

Oh yeah, like a bought one and I've always wondered about you know, old classic designs like this. Even if Casio still had the design files for this, would they be able to remake it today? Would those design files be useful at all? It'll be absolutely fascinating to know. I'd Love to hear from one of the old timers at Casio who actually designed a were involved in you know, projects like this because this was like really breakthrough technology back in 1983. But why didn't it last? Well, you know.

I Guess maybe the novelty wore off for these sort of like little touchscreen calculator watches. It was a very early 1980s thing and it pretty much died out by the probably the late 80s. I Don't think it survived into the 90s, that's for sure. But yeah, it's one of those icons of the 1980s.

the calculator watch in this one. You know it's not as iconic and well-known because it doesn't look like a calculator. it just looks like a normal watch. but it was absolutely remarkable.

I'd still rather have the CFX 400 of course, because there's a full scientific calculator with, you know, binary hexadecimal conversion as well, which was absolutely remarkable. But this watch, this is absolutely fantastic. I Just love the technology involved in this 1980 state of the art technology which still holds up today. just the design and manufacturing that goes into something like that.

I'd I'm just like always, in awe of products like this and you just take it for granted these little consumer things that almost throwaway prices a lot of engineering that goes into them so hope you enjoyed it. If you did, please give it a big thumbs up and as always you can discuss down below catch you next time you.