#690 – Clap on, clap off, lights flicker

Dave Jones: This is The Amp Hour Podcast. Released March 11th, 2025. Episode 690. Clap on, clap off. Lights flicker.

Dave Jones: Welcome to the Amp Hour. I'm Dave Jones from the EEV blog.

Chris Gammell: And I'm Chris Gammell of Contextual Electronics.

Dave Jones: It's been a while.

Chris Gammell: Yes. Hello. Hey.

Dave Jones: Hello. What's new, man? Is this the ASMR version? You're kind of whispering.

Chris Gammell: Chris is losing his voice. I had a meet-up on Monday, and then I have little kids, so of course everyone's sick all the time, including me now. Yeah, so my voice is a little bit raspy. I remember thinking, actually, oh, Dave used to always get sick so much, and it doesn't happen as much anymore. Oh, yeah, your kids get bigger.

Dave Jones: Yeah, exactly. Yeah, they're out of preschool and, you know, the daycare or whatever. Not daycare. We never send them to daycare, but, you know, the preschool-y thing.

Chris Gammell: Yep.

Dave Jones: Yep. Yep. Germ factory. Congratulations. Exactly. Yep. And they just slobber everywhere. Oh, yeah. It's like... Oh, they're adorable.

Chris Gammell: Yeah, I know.

Dave Jones: No, it kind of passed that. It's all good. Yeah. It's all good.

Chris Gammell: I did. So I did have a... I rebooted the meet-up, actually, and it's no longer on meetup.com because those so-and-sos, they doubled the price, man.

Dave Jones: Oh, did they? Yeah, because I quit that years ago. They were... like, I wasn't holding that many meet-ups, obviously, and I was paying this bloody monthly fee. What, they doubled it?

Chris Gammell: 90 bucks every two... six months or something like that, and then they upped it to 190 or something.

Dave Jones: Screw that. You can organize it for free on the EEV blog forum. Screw that. Yeah, exactly. Exactly. Yeah. Yeah.

Chris Gammell: We switched to Luma. I think I lost some people, unfortunately, but... What, Luma? Luma is kind of an alternative platform. You.LMA. You'll see... You see a bunch of links. I kind of, like, always skip past them, and now that I use it, I'm like, oh, okay. Yeah. But all the... a lot of the hardware happy hours that, you know, are a little collection of hardware happy hours around the country, the U.S., we use Luma, so it's okay. Oh, got it. All right. Yeah. Cool. It's definitely, like, they've updated it in the last 10 years, and they're not charging... Even if they... I think that they will charge for it at some point, but it's nice. It's actually nice, which is, oh, okay. Yeah, this is, like, things people should charge for. Okay. You know.

Dave Jones: Got it. Yeah, that was just a rort, the meetup.com. Oh, God.

Chris Gammell: Yeah. Yeah. Good riddance. Good riddance.

Dave Jones: Yep. Indeed. Let them die. Yep.

Chris Gammell: Well, you know, they were part of WeWork.

Dave Jones: Oh, were they?

Chris Gammell: Yeah, they got bought by WeWork, and then they got spun back out, and then they got bought by private equity. Oh, spun back out. And then the private equity thing, you know, that's... they jack up the price. They got regurgitated. Yeah. It's the same thing that happened to Evernote. You remember, I used to love Evernote. Oh, yes. I used to always talk about Evernote. Yeah, yeah. Same thing with Evernote. I didn't realize that's why it kind of went to crap, is they jacked the price up. You know, they stopped development on it, basically, and then it's just, you know, find private equity is trying to squeeze as much value out as the right to do that. Yeah. But I switched to a different one, and I actually... I use Joplin now, and a lot of people like Obsidian, too. They're all, like, note-taking apps.

Dave Jones: Right.

Chris Gammell: It's great. I'm taking notes in it right now for our show.

Dave Jones: Excellent.

Chris Gammell: Joplin. Got to tape that note in.

Dave Jones: You know what else is going to crap?

Chris Gammell: What's that?

Dave Jones: Alkaline batteries. I hate them. I've had multiple instances recently of products being almost ruined by my continually leaking alkaline batteries.

Chris Gammell: The products ruined, or your version of the products ruined?

Dave Jones: My version of the... Well, my actual meters here that I use, I'm dumb enough to leave alkalines in them, and yeah.

Chris Gammell: What is... Is there an alternative? I don't... You know, you do a lot more with batteries than I do.

Dave Jones: Well, there's... There's the alkalines. There's the lithium primaries. They're basically not going to leave, you know, but they're expensive, and they've got a higher terminal voltage. So, potentially, you've got to be careful about putting lithium primaries into some products. They may actually overvolt, because some of the DC to DC converters that are obviously hooked up straight across the battery, basically, they might exceed their maximum operational input voltage if you hook them up to lithium primaries, which can get like 1.75 volts per cell or something like that. So, it's actually quite high.

Chris Gammell: So, you've got a stack of four and...

Dave Jones: If you've got a stack of four brand newies, yep, that can, you know, that can really add up, you know. Meh, you can cut my guts out. Yeah. Yeah, because that's 7 volts, right? So, if you've got four, 1.... I think it's 1.75. They can, like, absolutely fresh, open terminal, unloaded voltage, right? And that's... Yeah, that's 7 volts. So... And a lot of DC to DC converters designed for 5-volt operation, they might have 6.5 volts max. Or something like that. 6 volts maximum. That are actually designed to operate from alkaline cells. So, yeah. Just be careful you don't come a gutter there. Anyway, so there's also... You can get the old-school carbon zinc ones, right? But the old-school... But the carbon zinks, they can actually leak too. And they can potentially do more corrosion than the alkalines. But they're less likely to do it. But the alkalines are famous for it, of course. Especially...

Chris Gammell: I've seen the effect. I've had the crusties in the back of the meter or whatever. But what's actually causing that to happen? What actually makes it...

Dave Jones: That's the... Well, that's the alkaline fluid that leaks out. And then when you combine it with carbon dioxide in the atmosphere, it causes... A terrible chemist. But it causes potassium carbonate crystals. God, I'm going to goof this off the top of my head. But yeah, they're the crystals that you see. So it combines with the... So it's not just... So that's when you get those little white crystals forming. That's basically extracted carbon dioxide from the atmosphere. And yeah, turns them into corrosive, horrible stuff. So that's why to neutralize the alkaline material, you add an acid white vinegar to it. So that neutralizes out... Because that's acidic and that neutralizes the alkalinity... Is that a word? Alkalinity of the alkaline fluid that's leaking out, basically.

Chris Gammell: Wouldn't it be like basiness? Yes.

Dave Jones: All that base stuff. Anyway, it sort of neutralizes it out. So that stops any further, you know, rotting of your copper and your plated steel terminal, battery terminals and all that sort of jazz. Got it.

Chris Gammell: But the actual leaking is just a mechanical, like... Oh, right. Liquid inside a container.

Dave Jones: It's a physical venting thing. They are actually designed to leak. They are designed to vent the fluid out. If the internal pressure builds up too much, they've actually got a vent, a physical rubber vent on the end of them that will actually burst.

Chris Gammell: Like temperature, vibration, that sort of stuff.

Dave Jones: Temperature, humidity, pressure. A lot of people say that the battery, that when you put them in a very... Like a hard spring battery terminal, that's actually putting pressure on the ends of the battery and that can contribute to it. But there's no real hard evidence for that. But, you know, everyone has their pet theory of why alkalines leak. And they leak more than what they used to. When I was a boy, alkalines never leaked, you know. Duracell's never leaked. And now they're called DuraLeaks. That is their nickname in the industry, DuraLeaks, you know, because they just leak so often. It's ridiculous. But all the brands do it, you know. Yeah.

Chris Gammell: Is there anything with devices that are just more efficient so the batteries have to last longer because there's less current draw? Is there anything like...

Dave Jones: No, I think it's just cheapening down of the manufacturing process. Just a continual refinement, saving every last cent on the manufacturing process. Yeah, I'm sure that's the main contributor.

Chris Gammell: I could totally see that being the case. Yeah.

Dave Jones: Anyway. Or you can put in rechargeable batteries, which they basically don't leak. They don't have a chemistry that really leaks. Really. Yeah. So there's a whole bunch of people who will ban alkaline batteries from their lab and home and everything else. And they only use rechargeable batteries in everything. So they don't leak.

Chris Gammell: And we say rechargeable. You mean like rechargeable, like double A's and triple A's and stuff like that?

Dave Jones: The double A's and triple A rechargeables. Got it. Yeah. The nickel metal hydrides.

Chris Gammell: Yep.

Dave Jones: And they don't leak really.

Chris Gammell: I had to do that for... I had... I think they're nickel metal hydride. I actually have a battery pack right here. One second.

Dave Jones: Hardly anyone uses the old school NICAD anymore. They're all pretty much the hydrides. Here we go.

Chris Gammell: Let's see. I had to get a replacement pack for my kid's Tony box. You know what Tony box is?

Dave Jones: No. I have no idea.

Chris Gammell: It's like a little... You buy these little, you know, 10 centimeter tall, like, tokens that are in the shape of an Elmo or Cookie Monster or Elsa. Right. Frozen. And then it has NFC tag inside it. And then it reads the NFC tag. It goes out the internet. It gets songs. It downloads them to the thing.

Dave Jones: Oh, God. Oh, God. Yeah. Okay. And then it just plays music. It's just a music player.

Dave Jones: Okay.

Chris Gammell: Yeah, yeah, yeah. It's very cute. It's a... It's a... It is a brilliant branding play because literally it's... I'm not selling you a record or a CD, which you can't really do these days anyways. Like, I'm selling you a tiny figurine for 20 bucks.

Dave Jones: An experience. We're selling you a... I'm selling you an experience. That's right. Yes. Exactly. Yeah.

Chris Gammell: And then the kids, like, it's very durable. That is probably the most impressive thing. So, yeah, this is nickel metal hydride. I just had to replace the batteries on it after a couple years. But I got to open the box up and the surprising thing there is the... I can send you a photo, actually. They were running an ESP32 S3 in there. Not too surprising for a consumer good use of Wi-Fi. But the storage mechanism was a SD card that was, like, RTV'd to the board. Nice. Oh, okay. Well, that's... That is a way to do it, I guess.

Dave Jones: Well, it's... You're... Even if you have to buy the socket for that damn thing or even if you solder it... I've seen the SD cards soldered directly to the boards. Actually reflowed directly to the boards because it's cheaper than buying the raw chip. You know, it's just... It's mad.

Chris Gammell: Yeah, there's just volume benefits from whoever's making the SD cards. Yeah, exactly.

Dave Jones: So, it's just crazy. Or you get some surplus lot somewhere, you know, of a million of these bloody micro SD cards or whatever. Yeah. Yeah, yeah.

Chris Gammell: I gotta... When this thing finally gives up the ghost, I'm gonna... Well, maybe I'll do it before then, but I could just take the RTV off. I'd like to just see what actually... How they store the files because this is also IP so like, I'm guessing they encrypt it. Maybe, you know. Oh, okay. Like, they're downloading it, storing it on this SD card but then, you know, I could just take that out of there. Boom. I've got...

Dave Jones: Is it going to be like in a fat format or I doubt it's like in a fat format or something?

Chris Gammell: Yeah, that would probably be the easiest one if it's coming off an embedded device. Yeah, just shove it

Dave Jones: straight into the PC and read it but, you know.

Chris Gammell: Yeah, right, right, right. Yeah. Yeah.

Dave Jones: We decided to do that GW meter where that's just a fat format so it actually logs data to the SD card and, yeah, it's just a standard fat format.

Chris Gammell: Yeah, what do you get to hide, Ren?

Dave Jones: Yeah. Yeah, well, exactly. But it means that you can physically... Well, because the original concept was that you wouldn't actually physically take the SD card out. We would simply use the SD card as the storage, you know, the flash storage medium and then you would transfer the data via the Bluetooth but then we realized that we had to rewrite... Then we realized that we had to actually add that to the boot code. It had to be in the SD processor, it had to be in the bootloader code to access all that and it was just harder to do and didn't have space and everything so we just went, ah, well, let's just, you know, if you want the data off the SD card, you've got to physically take off the back cover, pull the SD card out, shove it in your PC, you know, yeah, yeah. Unfortunately, that's just the way it went. That was just a design decision that we were sort of forced, forced our hand on, really. So, yeah. Speaking of design decisions, I just released a video this morning, I'm sure you haven't seen it, about continuity testing on multimeters, latched versus unlatched because the BM786 meter, which I sell, when it originally first came out, it had a latched continuity tester. So it's a pulse stretcher, right?

Chris Gammell: Can you just define the two terms in this context?

Dave Jones: Okay, a latched, well, an unlatched continuity tester is that it'll beep as soon as it gets a short on the probes, right? So under 40, 50 ohms or whatever, right? It'll just beep. But that means it, and if it's fast, it'll be sort of like infinitely fast. So it's sort of itchy and scratchy. Yes,

Chris Gammell: you do when you, when you put two, you kind of tap the two probes together. I see you doing those videos, right?

Dave Jones: Continuity tester, yes. Yeah. When you, you know, you're troubleshooting your PCB and you're checking for shorts and stuff like that. So you put one probe, one money in there.

Chris Gammell: I'm saying, when you're testing a meter, usually you're tapping the two probes together.

Chris Gammell: I am tapping the two. You've seen how fast it responds. Yes,

Dave Jones: how fast it responds. And if you just lightly touch the probes, and especially if you don't have the gold-plated probes, right, then you've got to get a little, a lot of surface contaminant on the probes, right? So they won't make, so if you only lightly touch them, you'll hear like an itchy and scratchy sound. It'll be like, I don't know, I can't do a buzzer, you know, sound. But yeah, it'll, it'll, it'll pick up every little single break in that thing. So it'll sound all scratchy, you know, if you just gently rub the probes together. And some people like that, but some people don't. Some people prefer that if the multimeter actually detects even a microsecond of low impedance, then what it does is it turns on the buzzer and, and the buzzer and a pulse stretches that out. So even if it, even if it just detected one microsecond worth of short, it'll stretch it out so that you can hear it. It's illegal. Like a one shot kind of. Yeah. And yeah, so that's called a latched continuity tester, but it's essentially a pulse stretcher, I guess you could call it. So it turns a short pulse into a longer pulse that you can hear and see if you've got one of those visual backlight things that turns on the lead backlight on the meter.

Chris Gammell: Does it have a timeout then too? Oh yes, yes. There's like a lower limit. Yes. And there is. And there is stretches too. Yes, exactly. A pulse stretches

Dave Jones: to 0.1 second or something like that. Okay. Just, just so that it's audible. So that's basically the difference between latched and unlatched. Unlatched is just raw, works as fast as it can, but you'll get all this itchy and scratchy sound depending on your probe contacts. But on the latched version, you'll, you'll get a nice solid beep and that will tell you. But one of the problems is if, of course, if you're probing a populated board, right? Trying to troubleshoot it, check for shorts and stuff like that. The bypass capacitors and other capacitors on the board, what do they do as soon as you apply voltage to a capacitor? It's a short circuit, right? And that will give you a false, that can give you a false beep. So when you're, usually when you're doing a troubleshooting a board, you're really doing it like quite fast and you're like, you know, just moving the meter over at many different points, just trying to find, you know, random shorts and things like that. And that can, you know, and if you hear this solid latched beep, then you know, oh, then you waste time tracing that down thinking that it's a real short when it's just a cap, you know, charging up. Yeah. So, yeah. So, it's a trade-off. Some people are fans of one version, some people are fans of the other version. And anyway, some people don't think

Chris Gammell: about this for a single second of their entire life. Exactly. Until they hear it on the app. Yeah, exactly.

Dave Jones: Because most people, you just make, right, you make your choice if you're multimedia, you buy it and you just learn to live with whatever, how every, idiosyncrasies. Yeah, yeah. Yeah, exactly. So anyway, but Breiman decided, no, they wanted to sort of like standardize on this across different models of multimeters. So they've, so they changed it in one of the firmware updates to the meter. They actually changed it from latched to not latched. And some people are going great and other people are going, oh, no, I want my money back, you know. So it's, and then just like in the 121 multimeter I talked about, we couldn't add that feature because we ran out of ROM space, you know, essentially boot space. They said, well, why don't we make it user selectable? And they went, oh, we can't. We don't have enough, don't have enough firmware space available to put in both features. Unfortunately, you know, to make it, you know, you hold down a button when you power it on and you can change the mode from latch to unlatch, which would be really cool, but unfortunately. And so there you go. Oh, by the way, there is a third mode of operation, which I think the 121 GW multimeter might be the only one that does it on the market. Maybe don't quote me on that. There might be one.

Chris Gammell: Chaos monkey mode and it just beeps all the time.

Dave Jones: It's a third mode, which is a beep on open, which is a beep on open. So what you do, which is great, if you've got, say, a cable that you think there's an intermittent break in the cable, what you can do is hook up your meter in this beep on open mode on the 121 GW. So it just beeps all the time. And then, sorry, and then, so when you, and then you move your cable, right? You twist your cable and you do whatever. And if there's any intermittent break in there, then it will beep.

Chris Gammell: I see.

Dave Jones: So it's kind of like the inverse of a continuity tester. Yeah, it's like you're passing current to the cable

Chris Gammell: and you're trying to see where the current, it's really like a current flow check. It's a current flow check, yeah. It's like a continuity, anti-continuity test.

Dave Jones: It's an inverse continuity test. So they, yeah, that's just another way to do it. That's a good idea. Anyway, so yeah, yeah. So there's, there's fanboys of both versions out there and they're now, you know, I haven't read the comments in the last hour, but I think they're just battling it out in the comments. Yeah.

Chris Gammell: If you're going to find people that do care about it, they're probably on the EV blog. They're on the EV blog. Discussing it. Yes, exactly. Yep. Well,

Dave Jones: that's, that's how it came up, actually. Somebody actually complained on the forum that, yeah, why, why does it do this? And anyway, I won't get into the whole thing about the threshold levels either. Under how many ohms.

Chris Gammell: Right. That's the, that's another point. You know, but that usually is settable on the, not always, but. No,

Dave Jones: on the 121 GW, you can choose between 300 ohms or 30 ohms on almost every other meter on the market. You can't, you just live with any value that they happen to set, which could be 30 ohms, could be 50, 100, 200.

Chris Gammell: And handheld, you're saying. Yes. Handheld. My bench meter can, it's settable.

Dave Jones: Oh, oh, is it? Okay, cool. Yeah. Yeah. Keith Lee 2000.

Chris Gammell: Right. Ah, yes. Yeah.

Dave Jones: Yep. But.

Chris Gammell: All right. Got a little test equipment. Got a little consumer goods and batteries. What else we got?

Dave Jones: I don't know. I've got stuff. I got,

Chris Gammell: I got a new, speaking of design decisions, I am, I am currently in the throes of laying out the tightest, tightest board for me ever. I've seen this. You showed it to me before the show. Yeah. For other people. But this is, I'm making an air tag clone. So.

Dave Jones: Is this for work? Is it?

Chris Gammell: It is for work. Yeah.

Dave Jones: So it's like a demo product, is it?

Chris Gammell: That's right. Exactly. Right. Okay. Yeah.

Dave Jones: And I presume it's going to be open.

Chris Gammell: It is. Yeah. Exactly. Cool. Yeah. I think there's probably other people who have done this sort of thing too, but I was kind of interested in being a challenge for myself and, you know.

Dave Jones: Right.

Chris Gammell: Being in control of the open source IP and all that usual stuff. And, you know, putting the sensors I want on there. Have you looked inside? I know we talked about an air tag when they came out. Oh,

Dave Jones: I've never looked inside an air tag, no.

Chris Gammell: Yeah. I was relooking at Colin O'Flynn, past guest of the show. He, he actually had a bunch of reverse, not reverse engineering, but it was just like doing teardowns and, and, and probing when they first came out. And so I was looking at his stuff and some of the other, you know, teardowns and things like it. And it's pretty, I mean, it's a complex little board for sure. It's definitely more complex.

Dave Jones: I didn't think there was much in it. I thought it was just like. There's two PCBs in there. There's two PCBs. Yeah. So how does it work actually? I thought it just regularly transmitted, just burst transmitted its location or something.

Chris Gammell: It is. It does have a beacon mode, but it's, and that is the primary find my type of thing. So usually it's in beacon mode. I'm not sure if it's a true beacon or if it's just doing the pairing. I'm not good at Bluetooth. I hopefully will be sometime, but there's like different modes. People who do Bluetooth think I'm an idiot right now, but, but there's, there's like a true beacon where it's just, Hey, the temperature is 23. It's just like regularly putting that out. And then there's listeners that might be, you know, basically it's like open. Excuse me. But then there's also advertising.

Dave Jones: I'm staring at the PCB now. Oh yeah. It's a little complex ring based beep. Yeah. Yep. Yep. And, um, really.

Chris Gammell: Well, so the reason that there's is different is, so they have two PCBs. They have a speaker. They have an true speaker in there with class D.

Dave Jones: Why is there a speaker? Why does it need to be for you?

Chris Gammell: So you can, so like a lot of these, these asset track, like these little Bluetooth asset trackers, they do it so that if, you know, you can tell where your keys are, your keys can transmit. What if you want to find your keys? Right. That's the hard part. So now your phone can then beep your stuff. And then they have to be loud enough to hear them.

Dave Jones: Dude, when I was a boy, all you had to do was whistle and your keys would beep at you. Are you aware of this marvelous technology? I would like to come,

Chris Gammell: I would like to come back to that, please. That sounds awesome.

Dave Jones: Let's come back to this technology. I'll try and find it while you're talking about the, AirTag. Okay.

Chris Gammell: Yeah. Yeah. So another thing that AirTag specifically, and like this is one of many, right? So like AirTag is out there. There's a Samsung one. Tile was out for a long time as well. Whatever. AirTag also has ultra wide band, which is how if people have an iPhone, you can basically then within, I think within 10 meters, it starts to actually do range, ranging and stuff like that. So it'll start to, you can, it sets up a compass. So it'll say, oh, you're within 10 meters. You know, it's listening for the ultra wide band signals and doing signaling back and forth with your iPhone, that sort of thing. And so there's just much more complex, stuff in there. It's also a user replaceable battery. So it's got the battery holder is built into the plastic case, which is very fancy mechanically. So it's a little bit thicker. So anyways, what I'm doing is instead I'm taking a CR2032 with, with welded tabs on there. And I guess I'll have to paint a little picture. So that's the 20 and 2032 is a 20 millimeter diameter battery. And I'm matching the size of the outer, the outer diameter of a air tag, but just for my PCB. So it'll definitely be bigger when there's a case around it. So I'm doing a 32 millimeter PCB. So I basically have six millimeters, six round millimeters to work with for all the stuff that I want to put on this board. And it is, and Dave's seen it. It is not a small amount of things. It is. No. It's a bit extra, I think is the, is the term that kiddos use these days. You know,

Dave Jones: much like single sided load or don't, I only saw the top side.

Chris Gammell: It's single sided as well. Yeah. That's another, another choice.

Dave Jones: Do you think about double sided load?

Chris Gammell: I had thought about it and I, I'm challenging myself not to mostly just to keep the bottom side flat for if it's in a case. I don't want to have to have like standoff and stuff like that. I want to just have it so it can truly sit flat. But another reason is because I'm, so I'm using NRF 52 840, which is an older version of the chip, but kind of, it's still available and it's still, it's still all I need really. You know, there's, there's the new 54 that's out, which is like lower power, but, and I'll switch to that eventually if the, if this goes anywhere, but it's got NFC as well. So you can basically have an NFC antenna. And so I'm just going to, I'll share with Dave just so we have a shared context, but we'll try and describe it here. So there's a 24 millimeter solder down, NFC antenna on the bottom of this thing too. And then just to list all the,

Dave Jones: and that goes over the battery. Does that,

Chris Gammell: it goes, so the battery is, the battery is flush with the bottom of the PCB. Yeah. So if I get rid of this, so the battery is flush to the bottom of the PCB. All right. The, there's two pads on the bottom that actually you solder the antenna down to. And then there's a, there's a ferrite core so that it basically blocks the RF energy from being absorbed into the, into the batteries. Oh,

Dave Jones: I was going to ask that. Yeah. If you're putting it directly on the bottom of the battery, doesn't that absolutely kill the range? Soak up all the,

Chris Gammell: all the delicious RF. Yeah.

Dave Jones: Whereas it looks like in the air tag, it is, they've got the coil outside of the battery in the middle. I think that's what it looks like. That's right. Yeah. Right. So you're, you're putting it directly over the back of the battery.

Chris Gammell: That's right.

Dave Jones: So it only transmits in one direction. Really. It's very, that's right. There's, there's two skews.

Chris Gammell: There's one that, one that goes up and one that goes down. Oh,

Dave Jones: you got two different skew. People don't know if we're talking about skew, we're not talking about clock skew. We're talking about stock keeping unit. There you go. SKU, stock keeping unit for your store. So you basically make two different versions. One transmits in one direction, one transmits in the other. Oh, dude.

Chris Gammell: Yeah. Yeah, I know. Come on.

Dave Jones: That's the ultimate, that's the ultimate cop out.

Chris Gammell: What? Why is it a cop out?

Dave Jones: Well, you want one product that transmits in all directions, you know, seriously.

Chris Gammell: Me? No, it would go into the battery then Dave. I want to go to go down. Yeah.

Dave Jones: But then you get another, you, I don't know, etch the antenna into your board or something. So that is not covered by the battery or something like that. I don't know. Okay. Yeah. I mean,

Chris Gammell: this is a rev a man. This is a rev a. So maybe. Yeah.

Dave Jones: And they're two little buttons on the side, are they? It's got little, yeah, it's got a reset. It's got a boot,

Chris Gammell: you know, use your button, that sort of thing. It's got a buzzer. It's got a magnetic detection, like a read switch, magnetic read switch. It's got a security module. It's got a weather sensor. It's got an IMU. It's got a microphone. It's got a.

Dave Jones: It's funny that the largest component on the board is the programming header.

Chris Gammell: It's the programming header. Yeah. It's a tag connect 10. Yeah. My coworker, Mike actually found out that there's a, there's a serial port you can get on the edge of a, 20 pin J link. So we're using that too, which is interesting. I never knew about that. Yeah. Oh, and there's LEDs or there's 12 LEDs around the edge as well to do like a little.

Dave Jones: What you could have done. If you didn't want to dedicate PCB layout space to the programming header, what could, what you could do is you could have castellated edges on the edge of your board with the pins. And then you can just press that against the edges. And the edge of the board becomes the programming header. So it takes up no physical space.

Chris Gammell: Yeah.

Dave Jones: On the board. So.

Chris Gammell: Yeah. It's not bad. Except then, then you have to make your own kind of interface. Oh yeah. You've got to. Yeah.

Dave Jones: But you only have to make that once, right? You've got to only make the one interface cable for it. And then, you know.

Chris Gammell: Oh yeah. Well, unless I'm making it for a bunch of people that I know. So that's. Yeah. Well,

Dave Jones: you can provide a free programming cable with every program. Instead of two different skews with the, you can provide a free programming cable. That's not bad. Yeah.

Chris Gammell: You can maybe do a flat side too. Like I do a little notch cut out to make the alignment happen, but maybe I can do that with a. Yeah. Yeah. Yeah. It's not bad. It's not bad.

Dave Jones: Anyway, that that's just a little, a little, a little technique for small boards like this. If you've got absolutely no room, you know, when your largest component is your programming header, then, you know, wow. You know. Yeah. Yeah. Yeah.

Chris Gammell: Yeah. And so this is the first time I've done a 0.4 millimeter BGA. Yeah.

Dave Jones: 0.4 millimeter pitch. I called it. As soon as I saw it, I went, yeah, that's probably 0.4 millimeters. It's a stinker. Yeah.

Chris Gammell: Yeah. And it's got a, you know,

Dave Jones: are they making much smaller these days? Can you get a. Yeah. You get 0.25. I'm sure you can. 0.25. Oh God. Yeah.

Chris Gammell: Yeah.

Dave Jones: It's sure they're used in latest Apple shoe phones. Right. And stuff. Oh,

Chris Gammell: they're small. I mean, they're basically going still looking down on the board these days. Yeah. Right. That's, you know, yeah, this is, this is nothing compared to what some people do. Yeah. Yeah. I just chatted again with Lucas Henkel, past guest of the show, who does the amazing animations on LinkedIn and stuff like that. And just like the scale that he's at for those modules. He put, Oh my God. It's just, it's, it's so out of my, my scope, you know, but I was inspired, but partially inspired by, by his, his stuff. So it's, it's, you know, I wanted to try out some smaller things, but this, this is not, this looks massive compared to some of the things that he's doing, which is pretty interesting.

Dave Jones: So have you built one of these yet?

Chris Gammell: No, no, this board is still in, still in development. Yep.

Dave Jones: And, and, and you decide, it's interesting. I noted straight away that you decided to go with a battery that has welded tabs onto it. That actually just sold it straight onto the board. So it's not sort of like user replaceable. You do need the specialized battery. It's not like a battery. That's right. Yep. So, right.

Chris Gammell: Exactly. And so if you compare it to like the, the AirTag, right, AirTag is definitely designed to be replaceable over time. This is, yeah, you would need a solder iron. Oh, is it?

Dave Jones: I thought the AirTag was like a, the Apple AirTag was like a sealed thing. It's,

Chris Gammell: so the inside, the inside is sealed, but then the battery compartment is not.

Dave Jones: Oh, is it? Oh, interesting. Yeah. No, it's nice. I have no idea about these Apple gadgets. Yeah.

Chris Gammell: There was actually just a hack that just happened to using the find my network. Someone just sent it to me in root, something like that. Let me see if we can find it. Yeah. So the find my network is basically all the phones are out there that like opt into it, which I think they do by default. They, they pass along these messages, right? They, they get a, they get a, I think, encrypted packet from the devices. And then they, they kind of hand it along to the network. And then you say, Hey, I lost my keys. Has anyone seen, you know, ABC one, two, three, four, five, six, seven, eight, nine, 10, whatever the idea is. And then the network kind of forwards it along to you and you could say, Oh yeah, it was, it was last seen, you know, at the, at the library or something like that, you know, based on, based on the GPS location. So it's like all these devices working together, but yeah, the nroot tag.github.io, we'll put this in the, in the show notes. This is some, some hack that's happening, right? You know, some exploit that just got reported. Um, so it's, there's a paper that just went out. So that's enjoy your security vulnerability. Apple people. That doesn't happen often.

Dave Jones: There'll be Johnny on the, there'll be straight on that. I'm sure. Yeah.

Chris Gammell: You know, as far as impressed as I, so I think I told you, I'm a, I got a Mac mini, like a Mac mini. Yes.

Dave Jones: Yes. You got the Mac mini. You, you, you were trying to sell me on it and I had a look at it, but I don't know. There's just no real. It's great.

Chris Gammell: It's really. Oh yeah. If I, if I had that,

Dave Jones: if I had that need, Oh yeah. I've been here an amazing. Yeah. Yeah. Yeah. It's really nice. Just for the price. Except if you want to buy extra memory, I did actually watch a lot of highness just did a video on it. He, he just did a video on, should you buy an Apple? Cause he's not an Apple person. Yeah. I tried to sell him on the Apple mini or something, but, and then he, then he went through the cost of it and they wanted to like cost this outrageous price for an extra eight gig of memory or something. So that's, you know, yeah. Oh, on the memory side. Yeah. Yeah. Exactly. Yeah. Yeah.

Chris Gammell: Cause you can upgrade the storage. Like Jeff has stuff about storage. You can, you know, that's usually replaceable effectively, but yeah. Yeah.

Dave Jones: They,

Dave Jones: they just charged an absolute shocking amount for, you know, to go from 16 to 12, any four gigs or something. Yeah. There's like,

Chris Gammell: there's a YouTube shorts and like Tik TOKs. You can see where people are just replacing the PGA themselves. Oh, really? Oh, it's so impressive. Oh my God. And then they, you know, they show it working, you know? Yeah. Yeah. But yeah. Wow.

Dave Jones: That's thoroughly impressive. I'm amazed that people have the guts to do that. You know, it scares the shit out of me.

Chris Gammell: Yeah. Same. You know,

Dave Jones: it still, still to this day, changing a BGA would scare the shit out of me. You know?

Chris Gammell: Yep.

Dave Jones: It's just not something that I've ever been comfortable doing. Yeah.

Chris Gammell: I mean, so I will say like the hardware, you know, both the Mac mini, the air tag, all these things, like the hardware is undeniably like just gorgeous. So well done. Obviously at scale too. That's amazing. I have been so underwhelmed with all like cloud things from Apple, everything. You know, the software is really nice too. Like the, you know, the Mac OS stuff. Great. Fine. Whatever. Every time I use their cloud stuff, it's just, Oh God. It's like, they just forgot to hire people. I'm sure there are tons of people. It's just, why is it that bad? I think it's, I think it's me, honestly. I think it's, it's so different from how I normally operate. And the people that are in like the Apple ecosystem are so used to it, but I think it is horrendous. As an example, you know, I was trying to help my mother get some photos off of her iPad when I was at home at my, my parents' home during Christmas. And it's just, the experience is so one note, like single way of operating that like, there is no flexibility in there. It's just, well, you have to do it the Apple way. And if you don't, then you got to go to a genius bar. Yeah. Oh, okay. Well, that's, I am very capable to do things and there's literally no, nothing else to click. There's no tutorial. There's nothing you can do. It's just like, all right, well just what they really want you to do is throw your iPad out and get a new one. Right. Yes. My mother should do, but yeah.

Dave Jones: Yeah. Yeah.

Chris Gammell: And yeah, new hardware would be amazing. Yeah.

Dave Jones: Unbelievable.

Chris Gammell: Actually, that is an interesting thing. Okay. So last Apple thing. And then I want to get back to my hardware. Of course, it is interesting. Their new iPhone came out. I'm sure you didn't see it. It's the new iPhone 16.

Dave Jones: I know. Some people bitched about it, not having some charger thing or something. Yeah.

Chris Gammell: All these people are upset about it, whatever. But the interesting thing is the modem. So this is the first time Apple bought part of Intel's modem group. And they're not using Qualcomm Silicon anymore. And so that is really interesting to me. Interesting.

Dave Jones: Right.

Chris Gammell: I think, yeah, I think that is going to be, that's the big deal, right? I mean, I work with modems a bit and they are kind of just a wacky space to be in. There's not a lot of players. There's not a lot. There's like a kind of a consortium of IP ownership. My coworker just wrote a great article about like how wacky modems are that I can link into. And, and just the fact like a new modem person, like a new group coming into the modem space is interesting on its own. The fact that it's Apple is even more interesting. Wow. And the fact that they're getting like really crazy, like power efficiencies that other phones aren't getting. That is, that's the jam. Like that's, that's, you know, so Marquez did a, Marquez Brownlee, who does MKBHD, does the reviews. And he, he mentions it and he gave it a little bit of, a little bit of airtime, but I mean, he's a tech reviewer. So he had to talk about all the stuff that's missing. Fine. Great video. Like always, Marquez is amazing. But the, I think the Intel, the, the, the Apple like modem silicon, the amount of stuff they probably had to do to get that like up and going and working and like with all the carrier certifications, all that crap. Like that is, that's going to be a big, that's going to be a much bigger article when, you know, future stuff comes out. And I'm really interested to see where all that goes because it's not like there's just a, you know, there's no startups that are going into the modem space. You know, it's just,

Dave Jones: is this potentially related to the satellite to phone, phone direct service stuff? Because you talk about a crazy, you know, energy efficiencies and all that sort of stuff that's kind of needed for the satellite to phone, phone direct service. Cause everyone's talking about that at the moment. Oh, they'll be out this year, you know, or if you're not out or trial units are out or something.

Chris Gammell: And Apple is one of the early stuff that's out there. Yeah. Yeah. For sure.

Dave Jones: I think they've already announced to hear, here in Australia, our telco partnered with Starlink to, and Apple, I think to have, yeah, straight, but it, but it, it isn't like you can stream and make calls, but you can send text. Like, so you can use it as like a modemy text modemy thing. Yeah. So, yeah.

Chris Gammell: I think it's,

Speaker ?: I think it's,

Chris Gammell: I, that's like the NT. So like non-terrestrial networks, NTN is like part of three GPP, seven, version 17, I think is when that started. That's like the, the governing board. Most modems aren't at that level yet. So like any modem that I use, I don't think I've used any modem past like version 14, like any of the IOT modems that are out there. They're all like 14. Maybe, maybe they're starting to edge their way up there. So, but obviously the handset stuff always kind of leads the pack anyways. So I, they are definitely getting that stuff and it's definitely coming down the line. Like you said, Telstra, Telstra, I'm guessing that was, yes. Yeah. Telstra has a Timo, Timo just partnered with Starlink too. And there's other providers other than Starlink that are doing this NTN type stuff. Yep. I think, I think we're going to have a couple of years of people be like, they said there's satellite and now there's not. And I'm so pissed. And I would, I deserve this. Okay. Well, but it is so cool. I mean, it's just, it's basically, remember me talking about like that book is eccentric orbits, like the one about the, about the iridium satellites that were started. yeah, yeah, yeah. Yeah. This is, this is what they thought it all was going to be. This is, this is the vision. This was, this was the future. Yeah. This is the vision, but like, it took so much additional space junk and so much like processing power and just lower noise amplifiers. Yeah. On the front end of, of these, of these phones. And it's just, and it's, but it is possible, which is still mind blowing to me. I mean, like you, you, I, I, I can't get the, the vision of like all the bad guys on their satellite phones. You know, they always have the antenna that like has to fold out and then it extends four feet, you know? Yeah. Yeah. Oh boy. I do think there's a lot of interesting stuff coming. Don't get me wrong. Cool. Yeah.

Dave Jones: But I'm not making any of that stuff. Right. So you wanted to know about the, the key finders. Yes. Yes. That you whistle at. You, you weren't aware of this back in the probably eighties, early, but definitely into the nineties. All the rage was when you would, this little key fob thing that you catch it, attach it to your key chain and you would whistle, you would whistle and then it'd beat back at you. It would, it would actually.

Chris Gammell: How precise would your whistle have to be? Like,

Dave Jones: I can't remember offhand. Did you know anyone who had one? Yes. I think I might. Yeah. I think I may have at one point, but I can't,

Chris Gammell: this feels like something like vintage, vintage YouTube type type stuff. That would be great.

Dave Jones: I have sent you a link. I sent you a link. There is a Wikipedia page doesn't give, but I'm sure these were around in the eighties and you would have to whistle. It was very temperamental or other ones. You would actually clap. So you'd give two claps like that. Okay. And your key chain would beep. It would beep back at you. And, and one of the things you would do back in the day is you would just walk around a shopping center or something and, and you would whistle or clap and to see if anyone's key chain responded, you know? Yeah. Yeah. So it's, there's a photo of a typical one there that, you know, there's a couple of little coin sales there, powering it and a little, you know, led to light up and flash. And there's a little chip on board thing on the PCB and that's it. And a, and a piezo buzzer. And I guess, I'm not sure of the tech that went into it. You know, there's just like a filter in there that, so the piezo transducer would be picking up the sound and also emitting it at the same time after it picked it up or something. Yeah. I don't know, but yeah, they got a long battery life. They had a couple of years at least battery life, I think. See,

Chris Gammell: that's interesting to me because like, how is it, it must have some kind of thresholding circuit that. It,

Dave Jones: it has a threshold in circuit with a filter, with a band pass filter and you had to whistle at a certain frequency, you know? So I'm not sure of, you know, the exact, the exact parameters of that, but yeah, these were all the rage back in the day. All the rage. Hmm. Oh man. Didn't you? And table lamps, table lamps that would give the clap, clap.

Dave Jones: I knew that. Turn your side lamp. Okay. Clap off. Clap on, clap off. And they would do the same for the key chains as well, I think, but I don't think they're as popular because they would false trigger, you know, all the time. Yeah. Yeah. The whistle had to be, you know, a specific, and that had to be a specific bandwidth for a specific period of time at a specific amplitude. And then it would, you know, yeah. Anyway, cool. Yeah. I, speaking of filters, I,

Chris Gammell: I learned, I'd seen this part name before, but I never knew what it was. I never bothered to look, but I found a saw filter. Oh yes. Yeah. Yeah. Schematic.

Dave Jones: I was looking at surface acoustic wave for those who don't know. Yeah. Yeah.

Chris Gammell: This is at 2.4 gigahertz and it's basically, it's just, it is what you were talking about. It's a band pass filter. Yeah. It's a band. It's a physical. Yeah. Yeah. Yeah. Huh. Yeah. You used them in designs and stuff before.

Dave Jones: Yes. Yeah. Saw filters. You could buy them in a little ceramic package or something. Yeah. That's what this was. Yeah. Yeah. Yeah. Okay. Yep.

Chris Gammell: Yeah. In this case, it was, I think it was just for interference and probably passing FCC testing because it was RF, but yeah, I've never, I've never used one because usually I'm just doing single, single, band type of things. Yeah.

Dave Jones: But they're, yeah. So basically for those who don't know how they work, I believe it's like a piezo substrate and then you would have a transmitting element and a receiving element on them. And then it would, yeah, it would, it would physically transmit inside the chip itself. It's yeah, but then, then it would, but, and the physical dimensions of the little, little transducer elements in there would determine the frequency of the filter. So yeah, it was, Oh yeah.

Chris Gammell: It says it's a, it's a direct analog implementation of an FIR filter. Oh, that's really interesting.

Dave Jones: Oh, really? Okay. Oh, that's really interesting. Yeah.

Chris Gammell: Wow.

Dave Jones: Okay.

Chris Gammell: Yeah. So it's like how you have like buckets in an FIR filter, like when you're doing it digitally. Right. It's doing the same thing and just basically like passing the waves along.

Dave Jones: The waves physically pass along the ceramic. I think they're a piezo ceramic substrate.

Chris Gammell: You're right. Yeah. Yeah. Yeah. Yeah. It says it's electromechanical. I'm just, I'm not reading Wikipedia, of course.

Dave Jones: Oh, okay.

Chris Gammell: Yeah. Cool. I mean, I, you know, RF's a new field for me still. You're right. Yeah. Many years later. And I'm not even,

Dave Jones: I assume people still use them. Saw filters. I haven't looked at that for years. I mean,

Chris Gammell: like literally I was looking on a board. That's where I found out. Oh, okay. Right. Yeah. No, this was on a thing in 91. I was looking at the, that had a similar, it has the 52 H40 on it. And so I was like, Oh, look at that. Is it on this one? No, it was, yeah, it was in this one. It was in front of, it was like a little black blob in front of the antenna. I'm like, Nordic releases the schematics, which is great. Actually all the files.

Dave Jones: Actually, they're probably still using phones. I wouldn't be surprised if they're not still used in phones. Maybe. I don't know. Yeah. Yeah.

Chris Gammell: I mean, if you have, if you know your, your band and you don't, you're not relying on like the harmonics, you probably don't want the harmonics. So.

Dave Jones: All right. It's amazing.

Chris Gammell: Anything works, honestly. This is. Yeah.

Dave Jones: Yeah. That's a bit of a, it's really a physics magic. That sort of stuff is like, it's materials physics. Magic. Yeah.

Chris Gammell: Put these little crystals in place.

Dave Jones: And yeah,

Chris Gammell: we should go. We should go to one of the, one of those conventions where they're like selling, you know, like energy crystals. Oh, right. Yeah. Yeah. And we should walk around to the tables and be like, do you sell saw filters? I hear, I hear that these have, have resonance that will heal me, but I really need resonance that will help me heal, heal my spectrum. Can you help me heal my spectrum? Oh God.

Dave Jones: I've, I've got a photo of one of those guys at one of those stands at, at Byron Bay. I think it was, which is like a hippie town here. Oh yeah. And they have the markets and you can, a lot of pot smoking out there. Oh yeah. It's all the surfers. And, oh yeah. And there's this guy that runs this hippie crystal healing stand. Oh my God. And he's got all these posters up along the front about, you know, you're being blasted with all this, you know, 5g energy and shit. Right. And there, and that guy, he would really benefit from a, from a saw filter, right? You know,

Chris Gammell: just keep it out, man. Maybe tinfoil hats are like the new saw filter, you know? Yeah. I've been wearing Pizio electric hats. That's what, that's what they really should have been doing.

Dave Jones: Oh, I'll see if I can find the photo of that for the, for the thumbnail,

Chris Gammell: but I think we've talked about him before. Cause I remember generating art about the crystal vendor. Yep. Mid journey a while back. So right.

Dave Jones: Yep. I'm sure we have. Yeah, but it's cool. Oh boy. Anyway. Yeah. What have we got on our list? I, I fond farewell to unmanaged 615. Thank you very much. Thanks for all the fish. He's had to check out of Reddit for reasons I won't go into, but yeah, thank you very much for putting in all the effort over the years to give us links and everything. Yep.

Chris Gammell: Yeah. Thank you. Thank you. Unmanaged. We've spoken about you here and we will, we'll think finally about your, your links and your,

Dave Jones: I've got me sending a mailbag thing. Once I've got a, I currently, over my shelf over there is an unmanaged 615, a magnet thing. You can see it. It's right under my speaker there.

Chris Gammell: Nice.

Dave Jones: Yes. Anyway, I put something on here.

Chris Gammell: Whoa.

Dave Jones: What do you got? From the EV blog forum. I just saw this last night or that. I think it's been going for a thread, which has been going for a week. Anyway, a newbie ask, retired engineers, how did you learn using oscilloscopes in the 1980s without the internet?

Chris Gammell: Yeah.

Dave Jones: It's actually a good question. It is a good question. One, one that I've answered.

Chris Gammell: I have no idea about because I was not neither using oscilloscopes in the 80s, nor did I really exist much without the internet. I, I, I did exist without the internet, but not in the electronics context.

Dave Jones: Right. Yes. Because like videos did not exist. The internet did not exist. You could not watch demonstrations of people using oscilloscopes. So how did you learn how to use oscilloscopes? Well, I've actually answered, semi answered this in my video, how I became the EV blog guy. I, a talk I gave at the university in New South Wales. Talk.

Chris Gammell: That talk was about 15 years ago. Just FYI.

Dave Jones: No, it wasn't. It was about two years ago.

Chris Gammell: Yeah. It was pretty close to the beginning of the show. I mean, you've been talking about it for long times.

Dave Jones: No, dude, I'm sorry. No, no, no.

Chris Gammell: You gave some talk about, okay. All right. No, no, that's another, no, a different, that is a different talk. That is a different. No, this is, all right. Sorry, sorry, sorry, sorry.

Dave Jones: You've got to look it up now. It is now like, well, I only put the video up six months ago, but it was a year ago. It was only a year ago. I gave this talk at the university.

Chris Gammell: It must have been a different university or something. Okay. All right.

Dave Jones: I will share the link with you. There it is there. Anyway, I, I actually show a photo of my bedroom because I got out the old film, like I got out the old photos and I scanned them in. I found an old photo of my bedroom and there at the end of my bed, our bookshelves. Oh my God. And these bookshelves are full of books and magazines and things that you would read.

Chris Gammell: I think that's the real answer. Yeah. The magazine.

Dave Jones: Right. Is that, and you would, and back then the manuals were great, right? So when you bought your oscilloscope, when I bought my first oscilloscope, yes, there was no internet, right? It was in the 1980s and you buy your analog oscilloscope. Mine was a 20 mega, 20 megahertz, dual channel, COS 50, 20 jobby. And it was very nice. And it came with a beautiful ring bound manual. And, and the manuals were great. They would show you, you know, what each control did and how, how the waveforms are supposed to look and stuff like that. The manuals were really good back then. So you would read the, so you would RTFM literally, or you would read articles in the various magazines of how to use your oscilloscope and stuff like that. If you didn't have anyone to show you, you know, if you didn't go to school, you know, that actually had a lab with somebody to show you how to use it. If you had to learn it on your own, then that's how you learned it. And yeah.

Chris Gammell: I think there's also probably a, there's a self-selecting, like there weren't as many oscilloscopes to be had, right? It was just a smaller market.

Dave Jones: Oh yes. And they're all, and they all work pretty much the same. They're all, you know, dual channel, 20 megahertz analog. Oh, if you're, if you're able to afford it, you might be able to get a 60 megahertz version, you know, maybe with a dual type. Oh, dual time base was killer. I'm telling you, delayed time base, delayed sweep, dual time base was the duck's guts. That changed everything. That allowed you to effectively zoom into a waveform. This is in the pre-digital age, right? These are on analog scope. So you can, you get your analog waveform and you go, Oh, I think I can see something in there. Can I zoom in? I'm like, you bet you can. You use your second time base to actually select a faster sweep speed. And then you would move. Then you would have a delayed sweep thing, which would then on your second channel waveform, it would, you would get a zoomed in version of the waveform that you're actually looking at. It was great.

Chris Gammell: Yeah.

Dave Jones: Do you have any idea what I'm talking about? Do you ever use a dual time base analog oscilloscope?

Chris Gammell: I have used it. I've used, I think just a single channel on my old scope. Right. Yeah. Nah. Tech 400. It's not the same. It's not the same.

Dave Jones: And then you had the delayed sweep. So if you had like a trigger point, of course, right. Cause there was no storage. Right. So if you had like a long period waveform that lasted like a second or something, for example, but you, so you triggered, you know, way over at the start on some trigger event, right. You set up your trigger. So you're triggering over here, but you really wanted to zoom in and see the waveform at a, you know, zoomed in on a further part of your waveform. How, how do you do that? Well, you use the delayed time base, which would delay. So it would trigger and then it would delay the sweep. So that's why it's called delayed sweep. So it wouldn't start sweeping across your screen until that lay period that you actually dialed in. To the front. So then effectively, then you could choose a longer time base and you could effectively zoom in to a part of the waveform that was much further down after the trigger event. And that was magical, you know, all these, all these little tricks to, you know, because we, we didn't have storage back then. Of course, once digital, of course you could get analog storage, but they were like, if you could afford an analog storage scope, you'd, you know, you were richy rich, right. Or some big lab, you know, to afford an analog storage scope. But yeah, so we had to wait until digital scopes came out before we could single shot capture stuff. And then that just changed everything, you know, being able to single shot capture. There was no more dual time base stuff. Yep. Yeah. Yeah. Although I think there is one, maybe two oscilloscopes on the market. That's digital oscilloscopes, modern ones that actually have a dual time base on them. But don't ask me to, maybe it's a unity one or something. Don't ask me to give you the exact brand or model. Cause I can't, but I think it might still be a thing. Cause technically there are some people out there who still worship the dual time base to independent time bases and have independent triggering systems. That's the, that's the trick, right? Is that, yeah, in theory, because a digital oscilloscope, you only have the one, one trigger event, and then you've got to rely on having a big enough capture memory to then be able to capture everything you want. And then to be able to zoom in on a point. Right. But there are, I think there's one, at least one model oscilloscope out there that has two independent triggering and time-based circuitry, circuitries in there so that you can trigger it. So you can have a effectively a delayed trigger kind of thing. Like we could get old school analog. Anyway, there you go.

Chris Gammell: Yeah. I was thinking back to like when I, I was learning after, like you said, after all the digital, digital storage came out, but like triggering for, for me was always like a tough, a tough learning curve. Like I just, for some reason, I feel like it wasn't, it wasn't just explained to me or I just, I couldn't rock it. I don't know. And yeah, I feel like that, that if you were forced to like even see a signal, you wouldn't see anything until you figured that out. That, that might be a good thing. Yeah. Yeah, totally. It did. Yeah.

Dave Jones: And free running, you know, and modes and, you know, normal mode and, you know, right. Yeah. All that sort of stuff. Yep. Hmm. I think I've, have I ever done a video on triggering oscilloscope? I've done a video. What number one 59 oscilloscope trigger hold off tutorial. There you go. And then I've done advanced oscilloscope triggering episode 1583. Oh, that's pretty recent glitch pulse run interval testing, the triggering. Jeez. I don't remember doing that one. Man,

Chris Gammell: which run that sounds like though. I remember there was a bunch of scopes that were talking about runs when they, as like a, they're like hard to capture. Right. But I remember there was a bunch that were doing that as like a, Oh, we can even capture that. They were doing some kind of intelligence. And it was like, Oh, it triggered, but it's like less, you know, some, some kind of binning, I think outside of the, the trigger, the trigger level. So they were able to capture run signals.

Dave Jones: Anyway, that was not a popular video. 26,000. No one knows what a run to this. You can explain it. Advanced oscilloscope triggering. No one wanted to know about advanced oscilloscope triggering. Most people want to know. Video. Then I've done a whiteboard video. What is oscilloscope AC trigger coupling? AC trigger coupling is different things. So I did, I've done a whiteboard tutorial on that. Well,

Chris Gammell: actually I have one other thing I want to talk to you about before we, speaking of AC, AC stuff. So I, I'm thinking about holding off on calling electrician, but I've got lights flickering in my house and I'm wondering if, what I should think about doing at that point. I think what it is.

Dave Jones: Are they old school compact fluorescents?

Chris Gammell: Hell no. God, no. These are all LEDs. It's definitely, and it's like, it's like the whole kitchen will flicker. It's, we have a washing machine on the second floor and there's a sub panel up there and I'm pretty sure it's like the inductive load. So it definitely happens with the inductive load. Like when the washing machine is like, it's driving the drum basically. And you can hear, you can hear it upstairs. You know, it's like spinning it around and you can see the lights flicker in conjunction with it. It's okay. Well that one, it's not good, but it's at least understood. Right. I'm like, okay, that, and then there's other times though where it's just, I think it might be. So we have a garage, we have a air conditioner out on our garage basically. And that's like a long distance from our main panel. And I think that might be kicking on. I don't hear it obviously kicking on, but then I think the flicker might be like the, the long inductance of the cable cabling going out there. I'm just like, Oh, what the heck? You know, it's just most of the time I'm just pissed. I'm just like,

Dave Jones: are they different brands of lead lights? Are they different brands or is all the same brand? Cause if they're all different brands, that makes it more puzzling. because if they're like, because then it, it must be the mains dipping or something like that.

Chris Gammell: That's what I'm, yeah, exactly. Right.

Dave Jones: Oh, well, we'd probe it.

Chris Gammell: That's what I'm thinking about. Yeah.

Dave Jones: Have you got a differential probe that you can safely probe with? No, I don't know. you're going to have to go old school and remove the earth. Yeah.

Chris Gammell: Yeah. I have a hundred, so I have a hundred X probe and I have, Oh no, okay. I got some, some cheapy handheld scopes and that's probably what I'll do.

Dave Jones: Usually, yeah, you can use like a battery powered scope. Yeah. Yeah. That's probably the,

Chris Gammell: yep. Probably the way I'll do it. Or I can use my analog discovery three and just plug it into a laptop and not, not, not ground. Yeah. What do you think about that, Dave? Is that a good idea?

Dave Jones: No, I don't recommend that at all.

Chris Gammell: Yeah. But it's not, it's not grounded. There you go. No ground.

Dave Jones: As long as you don't connect it to the charger. Yeah. Yeah. And even, and even if the charger is isolated, it's still AC coupled due to the Y class safety caps in the charger. Oh yeah. Yeah. Yeah. Trap for young players.

Chris Gammell: Yeah.

Dave Jones: Yeah. I mean,

Chris Gammell: if you can't pick it up and physically separate it from everything around it, probably shouldn't be, you know, plugging into the wall. Yeah. Yeah.

Dave Jones: Although, yeah, that's the only thing I can think of is that the mains is physically dipping. You're getting a brownout. You're, you're, you're getting brownouts on that sucker. Yeah. And that's, that's dodgy as, yeah. But, but,

Dave Jones: but, but you should be able to see that. You should be able to see it.

Chris Gammell: So just wait for a flicker to happen and just watch, watch the, watch the mains and see if it like flattens out the tops or something like that.

Dave Jones: Something like that. Because those lead lights, they're just like, they're not, we're using some weird earthen system or something. They're just straight across the active and neutral. Yeah. And they've got a full wave bridge rectifier in them.

Dave Jones: you know, so it must be a serious dip.

Chris Gammell: I'm sure this is like relative recency bias. But remember I had all the electrical problems in my old house. Oh yeah. Yeah. So like, Oh, that's right.

Dave Jones: This is your new house. Yeah.

Chris Gammell: It's a new house. I'm in a brand new house, man. Yeah. And it's about the same era. It's not like these are old house. You're a bad luck charm,

Dave Jones: aren't you?

Chris Gammell: Yeah. Yeah. Me and, me and electricity don't get along yet. The only thing I'm thinking about that, you know, like I think one of the easy checks, relatively low cost would be like, just switch all the breakers out. Like there's like just corrosion on the breakers, stuff like that. Like I could just do that, but I just want to like actually know what's wrong. So I think, I think the probing.

Dave Jones: Yep. Yeah. The first thing I'd do is probe it just to see that it is a brownout. Cause I can't think of any other way. It's going to do that on a simple lead light and a whole bunch of different brands at that. It's got to be browning out. Damn.

Chris Gammell: Yeah. And I should definitely do that. I'm still looking at solar. So I got to figure this out before solar. Oh, right.

Dave Jones: Of course. Yeah. Yeah. Damn. Well, damn. Yeah,

Chris Gammell: indeed. Yeah. Power. Electricity. Who needs it, right?

Dave Jones: Yeah. I know. Pesky electricity. Let's go back to the, yeah.

Chris Gammell: The scale difference is kind of, kind of wild sometimes. I also lived like pretty relatively close to a substation. So like the, the scale difference from like here to there, first off, it's great living near a substation because our power, our power run to the substation is very short. There's not a ton of like trees and stuff in between. So like our power has not gone out yet, knock on wood. And, but like the scale there, obviously it's very, very obvious. It's, you know, 375 kilovolts going down to, you know, whatever the, the local, local delivery is. And then,

Dave Jones: but then get public maps for that. Can you get public maps to see which, does anyone in the electrical industry know? Cause I would like to know where my house is actually, what substation my house is hooked up to. I wonder if there's a map.

Chris Gammell: That's an interesting question. Yeah. It does feel like something that like should be, you know, it's like a public utility. Yeah. You could be, but it's also kind of,

Dave Jones: kind of, kind of like, security. Yeah. Yeah. Yeah. Right. Yeah. You don't want people sabotaging a substation because they know it's going to take out this area, you know, and, and all my powers underground. So I can't even just go around and walk around and follow the cables, you know? Um,

Chris Gammell: yeah.

Dave Jones: Yeah. Hmm.

Chris Gammell: Yeah.

Dave Jones: Anyway.

Chris Gammell: Yeah. But just like the scale difference. I'm still like substation. Then obviously my house, you know, I get one 20, two 40 on the two phase, but then, you know, now I'm staring, I've still have the board up on my screen and just nano amps, you know, pico amps, just, just that scale difference. It's so wild. I know.

Dave Jones: It's massive. Yeah.

Chris Gammell: Yeah.

Dave Jones: Yeah. Like I'm, I'm staring at instruments right now. I can go from pico amps. And in fact, I can go from femto amps. I can generate femto amps up to, you know, hundreds of amps, like just in a bunch of instruments that I've got. The scale is massive.

Chris Gammell: Yeah.

Dave Jones: It's crazy.

Chris Gammell: Yeah. We're just, we're just touching on, we're just touching on the, the middle easy range. Right. Yeah. Yeah. Right.

Dave Jones: Yeah. I have done that video into the world of atto amps, which looks into a, yeah, and electrometer. Yeah. Crazy stuff. Like when you're literally counting electrons, you know? So yeah, it's nuts. I've also done that video where how many electrons does it take to light up a lead? I've actually done that video. I think it's like a couple of hundred. I think it's a couple of hundred electrons required to light up a lead to any visible level. So anyway, yeah. Fascinating stuff. When you start, start getting down there. Oh boy. Or right up there in the big scale. Anyway, good luck with that.

Chris Gammell: Thanks, man. Yeah. Yep. See how it goes. Hopefully I'll have, hopefully this summer I'll have some solar stuff to talk about. We'll see.

Dave Jones: Excellent. Sounds good. All right. Catch you next time. Yeah.

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