And we're up. Hey this is EV blog raw uh I was just assembling some microcurrents down here. uh wh? there they are in the back I was assembling some microcurrents and I went live on UST stream and um, some people suggested I should just, um, hit record and actually record this thing. So oh well.

here we go. It's me testing some microcurrents. Wow! Great fun! And I've got the webcam and the other cam attached to the thing. Here here are the microcurrent units.

They're over here. Can everyone see? Yeah, everyone can probably see I've already tested out 20 of them and I've got a total of 50 uh units. So let's um, let's go do a quick visual inspection. There it is.

There's a uh, there's a microcurrent unit Tada And they came. uh, they, um, came assembled I get them assembled here in uh Melbourne Well here here here in Australia um anyway, get them assembled in Melbourne by a guy there who assembles them in his garage. um which is great scen. Anyway, this is the microcurrent I get it assembled by a guy in Melbourne who assembles them out of his garage and uh, all I've got to do.

uh basically is uh, pop in a battery and uh, whack on a case and then we're right so it's pretty quick. The uh Cas is actually manufactured done if you can see in there. manufactured in Western Australia Beautiful. So it's uh got a fairly High Australian content.

This thing. it's uh assembled. Wow, it's assembled here in Australia the box is made in Australia I then finish assembly. andest here in Australia but uh, unfortunately.

um, the PCB is made in China of course. um, and all the components um come from the US they come from Digi key. there you go. dead giveaway and uh, I don't use any um, gray market parts or anything like that.

they're all uh, genuine parts. but um, there you go. and what I'm going to do is I'm going to assemble them in batches of um 10 basically and then I will uh, batch test them also in uh in three stages in batches of 10 and I find that's pretty much a good uh, compromise between um, uh, not wearing out my test gear here, having to change ranges and stuff which I'll go into, but uh, also, um, but you know it's it. It's the most efficient in terms of time and stuff like that, so that looks good.

One of the first tests is to make sure I've um to make sure the batter is in and make sure the LED works. I've already fully tested a unit. Um, so that actually proves proves that uh, that the components I've got a good and all that sort of stuff. They're the correct components, they're right and then you can just do uh, spot testing on the units.

After that, you don't have to uh, fully characterize each one like I'd be crazy if I try to characterize each the the full performance of each of these uh, units. That would be just nuts. So and it's a pretty quick uh process to I can probably I I can do Um I can do about 20 of these uh per hour? Um, sorry. I I can assemble um 20 of these per hour and testing? Um, doesn't take that much longer either.

So um I I haven't got an exact figure for it, but uh yeah, it's certainly not a long process that's for sure. So anyway, this is Eev Blog Raw. Someone suggested that I just turn the how boring is this my back to the camera. Sorry, and uh, just assembling these units.

Actually, let's move it over here. There you go, you can see me a bit better now. and uh, I've got to be care. I've got to remember to actually put the battery in many, many times I have uh, assembled the these things and I've forgotten, completely forgotten to put the battery in them.

so I got to unscrew them and put the battery in which is really annoying. So and one of the problems is I after I've finished testing them too when I've got them all lined up over here I've got to make sure that they're all switched off cuz occasionally I have shipped a unit to somebody. Um, and they've emailed me and said hey, you shipped it to me and it was switched on and the battery's dead you know oops I'm sorry yeah I got to be careful about that. um as I mentioned before before, I started recording this to a couple of live people who were here at the time they were um I mentioned that uh yeah, if I designed this unit again, I'd certainly put in a um a a auto power off um thing auto power off capability or uh, just give it such phenomenal battery life that it wouldn't um, actually matter.

So anyway, I didn't you know there wasn't a huge amount of thought that went into the design of this thing? it's just I wanted one for my own use so I did it and then I thought oh, you know and I wanted to make it look good I didn't want it to be bodgy and then I thought oh yeah, I could do a you know I could actually, um, get it uh, get it actually published in Silicon chip as a project that would be neat and uh so I didn't really go to town on the design. It's a very simplistic design so there's no not nothing fancy in it at all. But yeah, if I was to redesign it I would uh, probably not use the sh same chip I'd probably use a different, uh, different technique um I'd probably extend it down to much lower than what it currently goes to and I'd put in some intelligence to auto switch it off perhaps, but the thing is, you know it's only powered from one of these little coin cell batteries. So um, really, if you powered it from Double A's you know if you put a couple of Double A's in there or something it would run for, it would run forever.

Really? Um, it would run for many, many, thousands of hours, continuously switched on so you wouldn't have to worry about it. Um, and that's one of the tradeoffs with designing battery power Stuff is you know, what sort of battery life do you want out of your product and um, sometimes it's uh, it's better just to over engineer the battery in it and just you know, give it phenomenal battery battery life cuz I think it's incredibly important for battery powered gear to have a phenomenal battery life be it a multimeter or be it a a uh watch which I'm trying to design my Mark 2 calculator watch again at the moment I'm doing all sorts of things. um, actually, this could be a uh update episode. possibly? who wants an update on what what stuff I'm working on and I'm not looking at the screen so I can't get anyone's answers cuz I can't hear anyone.

So uh I will have to check out the chat window over there and see what's going on. Let me screw this one together and I will check out the chat window, see how many people we got and uh, all right, let's see the status of the watch. Project a guy standing in front of bch craft in some boxes and talks to what looks like no one Eagle an electric screwdriver? yeah see the Tronic stuff Tronic stuff's Gone John from Tronic stuff he's a fellow Australian blogger. If you haven't uh, checked out John's um website go to Tronic Stuff.com I Highly recommend it.

He's got some awesome Arduino tutorials and stuff like that. there so bit of a plug there from John but I'm sure everyone who knows my blog will know John's blog as well or you should. Um, well worth following one of the uh few people, um out there actually producing a shitload of content. um cuz there's a lot of people who, uh, who don't produce content on regular you know, on on a regular basis at least.

um anyways, um probably some. uh I did mention that I'm might give a background of well, a, um, no an update of where I'm at cuz I don't do update blogs anymore I've done a couple in the past um I occasionally do it on the live shows, but uh, what I'm working on at the moment is um I want to get these microcurrent units out cuz people ask for them I I wasn't going to do anymore. Um because I just lost interest in them Really? Um, um, but people kept asking for them. So I thought I'd do another 50.

So here I am assembling and testing 50 units and uh, what else am I working on? um I want to do a um well actually one of my projects is an LED Matrix project. it's a little um lead Matrix thing it's tiny. the the other ones on the market are at four times this size so they're they're much bigger. this will be a really small lead Matrix and that that's got a um atmail AVR um on it.

it's actually Arduino compatible. So um and the whole idea is you can join them together and make bigger lead matrices and stuff like that. That's a project that's been hanging around for quite some time and I haven't um got a around to finishing it. so I'd like to finish that uh, open S it it be open source Hardware of course.

um and uh yeah I don't know if I I'll sell a kid of that or not, but I certainly want to. Uh, certainly want to do it for my own use. Um and next up I Got an interest to do my Mark 2 calculator watch again and I was going to do a um I was going to do a Blog on uh where I was at with that actually actually showing some previous design ideas I'd come up with and uh, stuff like that so I I might actually do that. Um, but I think I've decided now that I want it to be a touchscreen watch instead of I was going to do before I was going to do the same as what I did and actually have a button based calculator.

but I don't know I probably think it should be touchcreen and I found a nice new little touchcreen that fits. um actually there's problem with it. the LCD fits in the size I want? it's got a nice LCD it does come with a touchcreen, but the touch screen is much bigger. The touchcreen overlay 8 n woohoo.

Um, the touchcreen is much bigger than the Um LCD itself which is really annoying. um I don't know. can you actually cut down a uh, cut down a touchcreen to size I've never actually tried it or uh, something like that I I don't know if you can. um, but uh, that might be a solution anyway.

so I haven't uh, haven't looked too hard into that. but I do I do want to do that I want to do the microw watch Mark 2 um I've got an Um I've also got a Um power supply a USB based Um power supply which is in a similar box to this. um and it's a project which has been hanging around for more than a year. I've had prototypes of it and um, but I've changed my mind a couple of times on that.

So uh, that is another project All right. Remind me to uh, talk about the rest of the projects. 2, 4, 6, 8, 10. There you go do in batch of 10.

Nice round number. Why not? So y there we go. All right time to test them. Um now what I've got here is I've got a uh Keithly? Um, I've got a Keithly uh, 225 current Source it's a that's the actual number of the model 225.

Um, and it's a really nice current Source I Highly recommend that you, uh, pick one up. Um, if you're after a general purpose current. Source Now I'm going to test these in three batches. Um, yeah.

three batches cuz there's three ranges on the microcurrent itself. uh uh, there's uh, there's H amps, there's microamps, and there's milliamps. Um, so I'm rather than I I used to I started out and I tested each unit individually and then I was constantly, um, flicking my current Source through to the different ranges and that was, um, really, you know, really annoying and timec consuming. Not very efficient and it would wear out the switches on my current.

Source I'm sure if I did too many. So now I just set it to um 100 Nano amps and I'm going to test the Nano amp range. So oh, wouldn't you know it? There you go. Yeah, I set it I forgot to put a battery in that one.

Ah, would you read? wouldn't read about it? All right? These sort of things happen too busy yapping away. So yeah, I will test each individual current range on each unit and you'll see just how quickly it actually how quickly I can actually do that. Um, it's not a not a slow process at all. There we go du missing battery All right.

So uh yeah, if you like this idea of this Eev blog raw, then let me know because um, it's not a regular live show because I don't do the interaction with the chat window I have no idea how many people there. We got 16 people, 15 guests, and 16 viewers. Hey awesome and uh, normally I that's my live show is answer ring is a question and answer type. uh thing.

So all right here we go. Now we're talking all right and um, yeah. so I've got it set to 100 nanoamps and uh, basically I'm measuring the input current and the output voltage here and it should be within uh, 02 %c and it is cuz that's what I claim for the unit. um that within point2.

So as I do, um I'll just do them all like this and you'll see that I don't actually have to change ranges or do anything like that. I can, just, um, pop it in there and that's it. It takes a little bit of time for the this range to settle cuz it's quite noisy. um well, you know it can actually easily pick up noise and stuff like that cuz it's on the lowest current range.

the other ones are a bit quicker cuz they're more stable. but that one's spot on. But yeah, that's pretty much how quickly how fast I can test um, these units, it's it's faster and more. Um, it's faster and more effective than testing one unit and then switching between the ranges and stuff like that I find it's just easier to do 10 at a time like this.

Have it on the right range that H helps turn the power on. that helps and that one's spot on too. And they should all be spot on because um I am I am actually relying on the tolerance of the resistors and I've fully tested one unit. So I know that the build is good and they all come from the same batch of Uh parts.

so it's highly unlikely that Uh one unit will be out of spec. although I've already found one today. Um, that was uh, it was. 24% I think it was instead of .2 Um, so I don't know what what's the go with that one.

but uh, it's very rare that I actually get one that's out of spec. apart from that mixup which you can see in a previous video where Digi key sent me the wrong. Well, well, the manufacturer sent Digi key the wrong Parts Uh, the wrong tolerance parts and uh, they ended up in my microcurrent unit. So, but now I'm avoiding that by measuring the input current as well.

whereas before I already had my my current Source already calibrated and I didn't bother measuring the input current and that's what. uh, caused the problem. So yeah, that's good. So they all.

So what I'm doing here is called uh, spot checking. It's just, um, spot checking in this case. um, it can go. Each range can go up to a volt or greater, but I tested at 0.1 volts or 100 MTS full scale.

Well, a 100 molts output. So if I feed in 100 nanoamps, I'm getting 100 m volts here out here. right smack on the meter there. So and if it's within 2% then I'm happy.

and usually they're well within that well. within 2% Like that one is 0, 4% right? It's tiny. Um, you know it's quite close. So I mean these aren't Ultra Precision units.

but they're Precision enough. So there you go: I've just gone through and tested the first range of those now I'll switch it to um 100 microamps and I'll go through all 10 again. Yes, it's a bit monotonous, but uh, this is what you got to do now. Um, someone before suggested, um, why don't I automate this test? Uh, the reason being is just the shin, uh small number of units I do like this is a batch of 50.

Um, as you can see, I can test these very quick and it would take me much longer to actually design. um, a custom test you for for this thing, some sort of better Nails tester or something like that. Um, it take me longer to actually design that and build it and test it and implement it than it would to just test these units like this. Um, like if I was if I was making thousands of them, if I was getting up into the thousands, then yep, I would certainly.

Um, whoa. hang on. That one's way out. That one's 4% out4 Wow.

There you go. Wow. All right. Well, there you go.

That's two Going to put that one aside and uh, keep going. That's pretty rare to get two fires out of my batch. Spot on. Um, so yeah, if I was doing thousands of these, I would uh I would certainly go to the effort to, um, do an automated jig.

there's another one. What's going on here? That one's also 4% High Wow. there you go. Wow.

All right, something is going on there. All right. something's really happening here. I'm getting that one's Point 7% out.

That one's 7, All right. Yep. I just had several in a row. That's all.

Um, that one's within point2 Wow. Okay, I got four so far out of this batch so they're slightly out of Tolerance and uh, it would actually be very interesting I Think to see that one's absolutely spot on to the least significant digit. Um I Think it would be very interesting to actually plot and graph this data and see the error histogram and see if it's actually a bell shaped uh curve? I'd Like to know what the what the shape of the curve is I'm down to seven units all right. Um, time to go up to the milliamp range.

so 100 milliamps and bingo I'll just do a polarity test here. uh to make sure it works in the opposite direction and we have a winner. that's actually a finished unit Bingo see that's how quick it is. it's uh, not that.

uh, not that fast at all. I've got to remember to switch it off and it's and it's done I've tested all three ranges and I've tested the polarity and it is sweet. Yep, go. So where was I Yes I was talking about um, histograms and things.

eror histograms I think it would be uh, very interesting I Love analyzing and graphing data like that. Um, you can find some real fascinating things in engineering by uh, just actually uh, data just analyzing data, plotting it on a graph, and seeing what the curve looks like and uh, I do believe if you got something like this microcurrent unit um, poity on that one I think then you would, uh, probably find it is a Um Bell shape curve A B Bell shape manufacturing curve for the tolerance of the resistors I'm assuming I don't know, but that's the interesting thing to actually plot it or it could just be completely random. Um, maybe you would have to have a high enough number or something, a high enough sample number to get some meaningful data out of it. But uh I think it' be fascinating.

So it's one very interesting thing you can do in engineering is to plot data and it's amazing the stuff that comes out of it. it really is. You can find some hidden. you can find some hidden phenomena that um, you wouldn't otherwise know now one that Springs to mind.

there is one blog I've done. If you go, have a look at it I'm not sure which number it is, but um, it's the one where I do the lead Li in for my back. uh deck out there, it's probably you know number 70 or 60 or something like that. It's a long time ago and if you have a look at that I plotted the Uh temperature data of that I plotted the temperature rise of my LEDs and um and and I noted this in the video I think I I pointed it out on the graph I think and uh is that what I discovered from plotting that uh temperature data was that I could actually see um, a storm I I could see a storm that came through and the wind picked up and it actually cooled down the LEDs cuz I had them outside and it cooled down the heat sink enough to uh, change the temperature by by a few degrees or something it was and you could see the dip in it and I correlated the exact time of that cuz I logged the time as well I correlated that with the Um with the storm that came through and it was.

It was spot on. You could actually see when the wind picked up and the the Uh based on the weather data and stuff like that, it was absolutely fascinating. Um, and that's you know, and that's a very simple thing and there's much more fascinating stuff I've discovered in engineering over the time by just plotting that data. So there you go.

I've got a whole bunch of uh, microcurrents done there and um, oh boy I could keep going. um, but jeez. I don't know, it's bit of an effort. what's the time? actually? 6:00 Ah, got to go to the gym in uh, 20 minutes.

so um, yep, yeah. so I think I'll stop testing the Uh microcurrent units for now and I'll do it again later. but um I was uh, telling you about um, my the projects I was working on I've also got another. there's another Uh project in a similar same boxes.

the microcurrent actually actually there's two in the microcurrent. There's another couple of Uh power supply projects I want to do as well and I want to do a Quadcopter design I think I've mentioned it before, but I want to do a an automated Quadcopter. Which flies through a canyon and uh, no one's ever done it before as far as I'm aware of. and um.

so I want to get into doing a Quadcopter? um and then just, uh. last night I had the idea. That foolish idea. Extremely foolish idea that I would, uh, attempt to build a open an open source pick and place machine.

Oh yes, um, the amazing headless Dave am I headless? No. I'm not. There's the webcam. yeah.

I I was I was searching eBay and I came across these uh, feeder reels for the you know, the the component reels and one of the hardest aspects of pick and place machines. and why? I don't think anyone has done one yet. As a, you know, well, any viable one as an open source project is because of the feeders. Um, there some dust on that? um is the feeders? like all the components come on reels like this.

Okay, they actually come on reels and um, uh, you have to. um, feed the tape? Is that loose? Yeah, here we go. Here's a loose one and you've got to feed the tape through. So you have to put the reel in some sort of, you know, some sort of holder and then the tape's got to come out.

and then the component has to and then you've got to peel. Then you've got to peel back the um, the tape on the back of it. But that's real easy. You just attach it to a a thing and then a sprocket.

They've got little holes in them like that along the bottom and you've got to have like a sprocket or some other system. um, that pulls it through and then you know it turns as it pulls through and then the pick and place arms got to come down and it's got to locate the individual component by visual. Um, usually by visual ID And then um, it's got to put the turn on the suction, lift it up, move it over to the board, put it down. So but you've got to have like to make a useful pick and place machine.

You can't just have one reel or something like that. You've got to have like 20 reel because you know, I Even a simple board like my microcurrent got I Don't know, at least probably 10 different components on it. So you'd have to have a pick and place machine that supported 10 reels. Otherwise, you've got to run all your boards through once, place all your components and then take off all those reels and then uh, run, then put the put the other components back on the reels and then run it through again.

And then if you've only got say five and you got 50 components on your board, you got to run your board through 10 times times. It's crazy. So um anyway. I Found on eBay they've got these cheap little holders for these like some sort of manual thing to hold these uh, pick and place reels in place like that and um and they've got like a little channel that comes out and they've got a a little bar which can hold back the tape and everything.

and it was cheap and it looks simple and I thought well how hard is it to add a little steeper motor to that to pull this through like that and uh, you know it I don't know I got tempted into thinking it's not. It didn't look overly hard to actually come up with a solution for an open source pick and place machine, but H I you know I know it's not going to be that easy. but I was just tempted and I still am. So I don't know.

You might see me spending the rest of my life working on open source pick and place machine, but gez, it's a lot of work. um I don't know my quad cop is going to be enough work compared to an open source pick and place. So um, and I was talking to people before about these, um about these bits of gear here these uh keithly um oh zoom in these Keithly current sources I'm going to have to do a Blog that's just I was just going to do like a tear down of these now. um if you're after, sorry for the people live people I Can't uh, zoom in any better than that? But uh, the recorded people are going to get it now.

I've I've actually got uh, four of these uh, Keithly instruments. one's down there. Um, this is a Pico amp current Source it's a Keithly model uh 261. So um, if you are, if you want to generate, um, very low currents, this one can go down to 10 Fmo amps.

That's Fmo. Okay, that's that's one engineering unit lower than Pico Okay, it, you know. Mil micro Nano Pico Fto 10 Pico so I can adjust that 10 P sorry 10 Fto amps, 20 Fto amps, 30 Fto amps Etc It's a brilliant, absolutely brilliant Um unit. and um, uh, because yeah, there it is.

you've got 10 the power minus uh 12, right? Which is um, uh, Pico And then um, you've got two decimal places beyond the Pico So 10 Fto amps incredible but uh, if but a more use. but it only goes up to a maximum of um, uh, 10 microamps or something. no 100 microamps sorry so it's not a it's designed for really low currents, but very handy if you have to generate incredibly low currents in the order of Pico ants or Fto ants but a more usable one. Um, will be this.

um, Keithly, uh 225. that's the model number 225 current Source Um and it only goes down to Uh1 Nano amps. Okay, so it it only goes down to 100 Pico amps but it can go up to 100 milliamps. Okay, so it's a it's a more usable um current source so if you check out one of those on eBay if you're after a really versatile current Source I Highly recommend that one.

Um, and then here I've got a um I've got a uh high voltage power supply. It's a Keithly model 240a and um, it can generate um anything from 1 VT up to um ,000 volts or 1100 actually. sorry, um, it can go anywhere up to 1100 volts and that's quite, uh, useful and down here I will do a tear down of these. um, but I I I Was really tempted to get this one too cuz I wanted to complete the set if you know what I mean, you know.

So um I've got this which is a keeply 260 model 260 Nanov volt source so it can go down to oh sorry I don't remember the uh the exact um I think it can go? Yeah, it can go down to um 10 Pico volts I I think um so 01 uh PCO volt 01 nenov volt. So it's a Nanov volt source and uh, don't ask me why you would want a nanoamp uh a nano volt Source But anyway, um so in the evev blog lab here I can generate um anything from uh, you know, in the order of uh, picco volts up to 1100 volts over the whole range, and anywhere from Fto amps right up to milliamps. um I don't actually have a constant current source for? well, No. I Your regular lab power supplies can generate, uh, constant currents.

Your regular bench power supply can generate constant currents up to the order of amps. Um so I can cover this massive range of Um test signals. and anyway, these, um, these bits of Keithly these bits of Keithly gear are really good. I Highly recommend you pick them up.

um, some. I think one of them uses tubes I think the high voltage power supply has got a Uh tube in it anyway I Have to do a separate tear down of those, but these are just really useful Um instruments to have. so if you can pick one up, uh, cheaply on eBay I Highly recommend it. Um, they're really good and even after all this time, they I I don't know what vintage they are probably U you know, 80s or something.

uh, vintage at best. So they're um I'm not sure how long they sold them for, but they're really well made. You can get the service manuals for them and they they're really quite nice. so highly recommend you pick them up.

So there you go. That's uh, Eev blog raw I should probably call it quits and uh, that's it. So if you like the raw, it's not a regular live show. it's just me doing whatever in the lab.

Today it was building microcurrent units and there they are. Aren't they beautiful? Oh all lined up there look. It's lovely. just absolutely beautiful.

Anyway, that's it. I'll catch you later.