- Parker’s Jeep Radio should be finished next week! Will have a write up either on the MacroFab blog or his personal blog.
- Crazy awesome PLC for the SAIM we found. See Figure 1.
- ESP8266 with expanded memory
- Protected I/O
- Built in Speaker and Screen
- Stephen’s FX Dev Board is 29% funded! Thanks everyone! New Content soon!
- FXdevboard.com is up and templates are available. Stephen just finished tubescreamer clone using the templates.
- The greatest resistor in the world is on order – Double Sided for resistors and caps.
- Will Super Caps ever replace regular batteries?
- AutoDesk moves Eagle to Subscription only.
- Free version, Standard is $100/yr or $15/month, Premium is $500/yr or $65/month.
- Has a chart comparing the price of Eagle per day and Coffee? Error in chart. See Figure 2.
- LEDs categorized by product bin?
- Stephen made an actual silicon die ICs in college! See Figure 3.
- New to the MEP! Discussions about PCB assembly and design practices! Mounting holes on PCBs. What to look out for?
Special thanks to whixr over at Tymkrs for the intro and outro!
About The Hosts
Parker Dillmann is MacroFab's Co-Founder, and Lead ECE with backgrounds in Embedded System Design, and Digital Signal Processing. He got his start in 2005 by hacking Nintendo consoles into portable gaming units. He also runs the blog, longhornengineer.com, where he posts his personal projects, technical guides, and appnotes about board layout design and components. Parker graduated with a BS in Electrical and Computer Engineering from the University of Texas.
Stephen Kraig began his electronics career by building musical oriented circuits in 2003. Stephen is an avid guitar player and, in his down time, manufactures audio electronics including guitar amplifiers, pedals, and pro audio gear. Stephen graduated with a BS in Electrical Engineering from Texas A&M University.
Host 3 00:10
Hello and welcome to the Mac fab engineering podcast. We are your host, Stephen Craig and Parker Dolan. This is MAC fab engineering podcast episode number 51. Sofa professional. Ooh, yeah. So what's been up Parker? Jeep radio? Yeah, update in a while, mainly because I've been waiting for my audio switcher level adjuster, combo board to get built. And it's only in or only it will be funny enough, it actually got shipped out of macro fab, and going to the old macro fabrication. And so it will come back tomorrow, hopefully. Okay. Yeah, so I'll get that. I'll get that board. And I'll probably work on the weekend. And hopefully next week, I have an update either on the macro fab blog. Depends if they allow me to put that kind of content on the blog, or on my personal blog. Cool. I'm trying to hopefully get on the macro blogs. I think it deserves to be there. Yeah, yeah. But I mean, it's a project you've been working on for a while. Yeah. It's just not an official Mac fair project. Sure. Sure. But but you'll have an update. Next podcast. Oh, yeah. Totally cool. And then this is something mean, you've been working on? Yep. Because we've been doing a lot of machine automation. Working on getting conveyors working at macro fab. Well, more than the conveyors we have now. Basically, IoT, everything. Yeah, doing a lot of control logic and looking into systems that can work for us. Yeah. So we may have found something that's actually really cool. Yeah. So we found the or you found these? I didn't find it. Yeah, I've actually found it over the weekend. And
Host 1 01:53
I as soon as I saw it, I shot it right over to Parker. Yeah, I need to look at this. I looked at I think I just pulled it up. I'm like, Yeah, let's order two on Monday.
Host 3 02:03
So these are PLC controllers. They're not true. PLCs not in the traditional sense. Their PLC is in terms of hardware. That's right. And they look like they look like a PLC. So it's got an 80 Mega 2540, your big honkin chip, lots IO in there. It's got an ESP 80 266 Wi Fi. It's got all protected IO relays, digital and digital out. It's got analog in Yeah, it's got a bunch of analog ins. And it's got Rs 232. That's got the kitchen sink. Yeah, it got a screen on it. Packed to the tee. Yeah, pack. It's $90.90 bucks. Yeah. And it's called Open PLC. Yeah. And it's, uh, yeah. And if you just search on Amazon for it, you can find them the I believe the website is www.plc.us. Yep. So they got that one. Yeah. Yeah. I wonder how much that domain cost because three letter is, here's the thing, their website kind of looks stripped down. And when you go to it you like, this doesn't look really great. Yeah, that website definitely is circa 2002. Or earlier or early? Well, it's not. It's definitely not in tables. No, definitely. The left side is though. Anyway, it doesn't look great. But the product is cool. And we actually already have two of them in Yeah. And we've been playing around with them. In fact, we got them in. And so what's funny about it is you open up the box. And inside the box is the PLC and an antenna and a little bit of instructions that basically shows the color instructions, right in perfect English. Well, it was designed and it says it was built in America. I don't think it says built I believe that I believe somewhere on the website. It says okay, I could be wrong. The PCB does have an American flag on it. Yeah. But the solder quality isn't the best out there. Sure. But well, we did only look at one board. So yeah, we can look at them to the board. We will say that, but so the thing is like I get it and like, Oh, this is cool. I got to turn this on and see if there's a program. rd. You're like this guy be Democrat? Yeah. There's got to be I load this thing up. Yeah, there is a demo on there. And it is not just like, hey, welcome. I'm a PLC. It's like a demo demo. No, it No, it is Hello, and welcome. It actually talks to you what I mean, like it's not just like text that just shows up and says I'm a PLC now or something dumb like that. Like it. It has images it has, oh, we forgot to mention this thing has an A speaker in it. Yep. So it actually talks to you. Yeah. And it steps you through a bunch of screens and you can activate relays, you can. You can look at the state of all the pins. You can turn them on and off. It does all kinds of crap it like wow, this is actually extensive for a demo. And the cool thing about the demo is it basically does everything With the hardware and so and all that, that code is open source, you go on their GitHub, and it's there. Right. And the cool thing is all of the demo stuff like the the images that are displayed on the screen, and the wav files that are played, actually come on an SD card that comes with the device, but you get a you get a micro SD card. Yeah, four gigs, eight, excellent eight. So it's not huge. But I mean, hey, it'll run most of your stuff. Regardless, if you wanted to take their code, you could basically just take their demo, and convert it into anything, all of it is there. And what's cool is they have it chunked out pretty well, that it all everything is just functions in libraries that are already pre done for you. So including, like the Wi Fi, all the touchscreen capability stuff. It's, it's pretty nice. And did we mention that this is Arduino compatible? No, I was just about to bring that up. Because we said it's almost like a PLC. Yeah. And the difference is a PLC uses ladder logic programming. This uses standard C with the Arduino sprinkled on it. Right? So if you you can, you can program it directly from AVR studio if you felt like yeah, or you just plug it in? Because it has a USB. A, B, B? Yes. It has a USB B on the side. You just plug that in and go into Arduino. And you're you're already rocking on a PLC. Yep. So by next week, I hopefully we have like, we've actually written code for it and actually tested it out. Yeah. I'm hoping to move some motors on it next week.
Host 3 06:40
So yeah, we actually have a, what we call a hand place bench, out on our manufacturing floor, that when when products come out of the the our pick and place machine, occasionally, there's still some parts that we need to place. By hand. It's things like if there's a one z or A to Z part, we'll place it by hand or weird package or something that the machine can't pick up. Well, we're hoping to use this PLC to control all the conveyors on that bench. Yep. Which Hey, for 90 bucks, you could just put switches and motor controllers directly to it. That's pretty awesome.
Host 2 07:16
Yeah. And the cool. Well, the reason why we have a bench that's like that is most benches like that costs, like eight to $9,000 used. Yeah, yeah, yeah, we got this thing for like, what? 700 bucks. Yeah,
Host 3 07:29
We got a cheap, and it has some beefy motors on Yeah, it's got like, I think they're 16th horsepower motor or something like that. They're they're way overkill. They're just size of like, a 40. Size of beer. Or malt liquor, I guess. I like how that's your unit of measurement or something of a can size. It says well, it's definitely a really big cans.
Host 1 07:55
The squeeze bottle for these squeeze bottle 40. Yeah, actually, it's about that size here. Right. So yeah, we'll give an update on that. They're pretty cool. Yep. Ah,
Host 3 08:07
So epics done board. Epics dev board is now been live for a week. Yep. And we are actually so we got some some people who put some stuff in before we even wrote our show notes. So we are further along than the percentage in our show notes. We're just under 30%. Funded after after one week. So yay. Thank you, everyone who's who's gone and checked it out. I like how many people have bought us beer? Yeah. So the first option is is a just support us with beer and we have a good handful. Yeah. I think it's like 1516 people bought us some beer. Yeah. Hey, thank you, everyone. Cheers. Cheers. So along with the Crowd Supply page, if you go through this, there's this information. But I think it's worth noting, we have FX Dev board.com all one word. And on FX dev board comm we have a bunch of cool information, some templates on building certain circuits and pedals and things like that. But we also have some schematic and PCB templates, in case you ever want to take this and do something more with with your own circuit. Yeah, and you've got a already have a that excuse me, you already have an example schematic up there, right, we actually have three now. Okay, so this information is very out of date. I have written down Yeah, so So we haven't we have a bunch of good information on there. And we keep adding more. I've been adding a lot recently. So yeah, we have we have some schematics up there. And I think we're going to be putting some bill of materials and and I'm going to be sharing some projects over Mouser actually, because Mouser has their whole share a bill of materials things such as you can give someone a link and they just click Buy and all the parts show up. And we should do is is klenow Mouser has ability I'm pretty sure Digi key does where you can just paste a file into there in a certain format. Yep. And then you basically fill a card that way, we probably should do that with Digi key as well, because there are some people that are up north that are like us with Mouser that they get parts next day. Yeah. For ground shipping. Partially do same thing with Digi key. You know, I'll look into that. So I already have both of those capabilities with Mauser available. But But yeah, I'll check in Digi key. That's a good one. I just,
Host 1 10:30
I love Mouser. Yeah, well, we we both do. So yeah, go check out FX Dev board.com bunch of cool information on there.
Host 3 10:38
And then the greatest resistor in the world, the greatest resistor in the world is on order. Yes. So it's on its way. We did go ahead and spring for the update. And we put 40,000 resistors on one side, and 40,000 capacitors on the other side. I felt like that was actually going to be better. Seeing as the size of the board is is 10 inches high by like 15 Something wide. I can't remember exactly what it is. But I didn't want there to be 40,000 resistors all on one side and no copper on the other. Because that's pretty much guaranteed to warp warp like crazy. So I figured if we have generally the same mass on both sides, it should be pretty stable. Yeah. So hopefully we'll see that we got we'll see that next week. No, it's probably going to show up week after really okay. Yeah, we I think it was like 275 bucks for the PCB. It's something in that range. Yeah. So pricey, but, you know, there's, this whole project started to make a cheaper precision resistor. Now, it's just, it's got a little stupid. I actually told my good friend about it. And I was explaining the whole thing. And then he was like, Well, what tolerance, is it? I will? Oh, you know, it's 0.005% tolerance. He's good. And he looks at me goes, couldn't you just buy that off of Mouser? For like, a whole lot less? And I was like, Yes, but No, no,
Host 1 12:09
No, we our rating is through the roof. Yeah, we have to do this. This is shut up.
Host 3 12:17
We are gonna have to pump a lot of power through it just to test it. Of course. Of course. We have to. We have to beat it up. Yeah. And we'll we'll get a we have a source to get a seven and a half segments. multimeter. Yep. With graphing capabilities. Yeah. So when we hook it up, we can actually graph how current changes through it and all that stuff while we heat it up and apply power and all that crazy stuff. And I'm going to try to get a FLIR like thermal imaging camera, so we can see if stuff heats up unevenly. Yeah, see how I do want to put it in like a cooler or something like that. So we can kind of negate any air blowing over it. And the temperatures pretty stable. And we probably have to let it run for like, two hours to be stable in temperature. Though, it's ridiculous. still fun. Okay, on to the RFO RFO. On this is a interesting Hackaday article I saw. I'm not really wanting to talk about too much about the article itself. But it's a it's a good topic. It's a will supercaps ever replace regular batteries like lithium. So the premise of their article was basically explaining that two different types of technology, how much power each one can hold right now. The future, all that stuff. So it's mainly comes down to to power density. Whereas a lithium battery can hold, you know, 1000 times more electrons basically, then a super cap. Mauss thinking is when you have to because one of the big things about supercaps over lithium batteries and other batteries is they can charge almost instantly. I was about to say the biggest thing between a cabinet and a battery is their ESR. Yeah, a cap has like ridiculously low ESR correct. So you can pump a lot of power into it to charge it up. Now I'm thinking I'm like, Okay, so you've got your little tiny cable that you plug into your phone, right? So let's say you can make a super cap that fits in your phone that can power it the same way. Okay, so you need the same amount of juice to go in. So takes two hours to charge your phone. What at you know, two amps at five volts? Yeah, well, now you're gonna try to do over two hours. You're gonna try to shove that into like two minutes. Yeah, so you're gonna need a like, you know, one OTT USB cable. Plug into your phone. Right? Well, I think I think batteries with their high ish or higher ESR there's there's a A level of safety that comes along with Yes. Yeah, like a nine volt battery with its terminals being so close together. You touch it and you don't have any problems. That's not gonna be an issue. I mean, testing nine volt batteries, do you look the terminals? Right? Go Lika supercap that's charged nine volts and has 1000 milliamp hours in it. Yeah, and I'd ruin your day. If I ruin your week. Yeah. It'd be like Jar Jar and Phantom Menace? Oh, gosh. Ruin. He's ruined more than a week. He's ruined an entire franchise. Child. But yeah, so that, just thinking about it on the surface. That's probably the biggest difference. I wouldn't be surprised if supercaps could replace batteries, if they get the safety factor out because batteries have the inherent ability of being swapped in and swapped out? Yeah. I guess sort of, in a way, if they're not gonna sell well, high end lithium batteries have really low ESR as well, right. I mean, you can pull like, you know, 40 or at sea. I think there's 100 C batteries too. For those that know the C rating of A batteries, basically, how much more current you can pull over its writing. So a, a two amp hour battery. If it's rated at one C, you can pull two amps off of it before you basically start thermally hurting the battery. Whereas as 100 C, you can pull 200 amps off of it. Now you'd only get like a couple minutes runtime, but you can pull 200 amps off before you destruct the battery for thermal shock. All right, it heats up and hops stops. Yeah. But yeah, inherently, I think it's about being able to plug them in and plug them out is what this is kind of talking about. Well, yeah, but what if it's in your cell phone? Because I mean, most cell phones nowadays you can't replace the battery. So it's technically safe that way. Right. Right.
Host 3 17:02
I think I think your base, we need to figure out how to make screens, much more low power to start using supercaps. Because that's what draws so much power in your phones nowadays. Yeah, talking to the tower, you know, playing, you know, or computing all the games and stuff you're actually running doesn't take that much power. It's the screen that takes the most amount power. Hmm. Well, I also the way that like super caps, and I think they also have ultra caps, which are even beyond super caps, the actual physical mechanism, the way they work internally. It's really interesting. But they, it's not really great for shocks. No, like, it doesn't handle. Like if you drop a phone, you can puncture that, and that's smells game over. Yep. for it. It's just not very robust. If I remember, right, like regular capacitor, they basically take the two plates, put the dielectric in it, and they roll it up for electrolytic. Yeah, like in like a tubular cast. And so it's similar, but it's almost like a a mesh, is what the stuff is, like, if I remember correctly. Yeah, well, okay. So they, they, they do that and then they grow the other plate. Okay, basically, you have you have one plate, you apply a dielectric in, there's multiple ways to do it. And then on the other side of the dielectric, you grow. That's how they increase the capacitance so much. Well, yeah. Okay. So they get they go from micro meters to nanometers. zactly and plate with that. That's it. That's exactly how thickness, right? Yes. Yeah, right. They the the distance. So capacitance goes up by the square root of R, on the plates separation. So if you can get it nanometers, that's how you can get like 100, micro farad, tantalum cap, that's an N 1206 package. Because they, yeah, because things are grown on the Microsoft. That's also why they one of the reasons why they catch on fire because they dump an enormous amount of energy into a really small package, if for any reason the tantalum is is and that's why I tend to come so probably so susceptible to reverse biasing, or over voltage is because those plates are so close together, right? That you can easily just punch right through which so that's why they they're, they work really great, but they're not amazing at being robust. Now, for batteries are a lot better. I won't, I don't know. Well. I wonder if a super cap will blow up or a gel pack lithium and packed. I bet you the lithium gel pack will blow first up if you puncture it, or just hit it with a hammer. Will the gel pack actually explodes due to chemical reaction, right? The Super capital just short? Yeah. So they're both bad in different ways. Yeah, so one will probably just make a little spark or big bark. Yeah, it was bad for the other one will cause fire smoke. You know, you know, I think I think the Samsung batteries actually, they had to land emergency land airplane because someone had one that exploded. Wow. So well okay, so I guess it's different if you have vibration or large amounts of shock versus literally puncturing the device. But you know, I bet you cell phone manufacturers test punctures, probably. I'd hope so. Yeah. So to answer don't use your phones at the blog bullets by the way. Yeah, just explode. And then the bullet still kills me. It'd be like reactive armor. But really bad. It's, it's not reactive armor. Well, I think reactive armor is more like proactive armor. Because I think they actually they detect the round, and then they explode before the round gets there. Uh, there's, there's a whole bunch of Yeah, maybe. It depends on their thickness and it depends on I've seen both of those. Okay, yeah, they can detect like heat and they and things getting close to them. And then yeah, Abrams tanks, go look at Abran tanks, armor. There's actually a really great YouTube video where they discuss the evolution of the armor on a neighbor tank. Super cool. It's that that platform that's actually a farm should be a topic for future net is like Abrams tanks and like, how crazy the electronics are in those tanks now. Yeah, the only the Abrams tank is the only like, modern, like, I guess the battle tank that has an unrivaled barrel.
Host 3 21:48
Weight. It's just a straight barrel. It's a straight barrel. Hmm. I didn't and they use electronics to basically they shoot enough rounds out at the range. And the computer knows how to shoot that barrel. And so it knows the drift and how the rounds are going to hit. So it doesn't need rightfully. Oh, it has like it compensates. Oh, that's awesome. Yeah, because they do that so they can shoot different rounds. Whereas our rifle barrel you are limited. What kind of rounds you can shoot the depleted uranium? Yeah. Or whatever they use. Yeah, I think it's actually high explosive. But I'm sure they have a variety. Alrighty. Yeah. It's like going to the supermarket. What round you want? Anyways? The topic? See, I think eventually we'll probably get super caps. In everyday devices, prices gotta go down. You know, it used to be lithium batteries were astronomically expensive. Right now they're almost in anything. Yeah. Right. So I think just the technology improving and and getting stuff, you know, closing the the maybe after nanoco pico meter. And and Yeah. I think if they can do that with what we actually talked about on a previous podcast, remember, they were talking about, like silicone grown capacitors and getting high capacitance on a die? Oh, yeah, maybe. Maybe on that level, you're down to the angstrom. Level. But you have to have some pretty exotic materials to avoid arcing. Archies and yeah, and voltage puncture, but that would be
Host 1 23:25
Super cool. Yeah. Alright, topic to Autodesk moves eagle to subscription only Oh, this this probably makes you so mad. Actually. No, cuz
Host 3 23:37
I calculated the price and it actually works out cheaper. Oh, does it release for me. Okay. So still, they simplified all the I think we talked about this on a previous podcast. Okay. One of the earliest ones where they simplified the pricing structure. Right. Yeah. And then they said they were gonna do subscriptions. People complained so they didn't do subscriptions. And then now they just said like, they just flipped the switch overnight now subscription. What but just a few months ago, they got bought out. Right? No, that was back then. too. Okay. Yeah, they oughta spot Eagle. Eight, nine months ago, man, I thought we talked so much earlier. Yeah, it's a long time. Okay. Yeah. Anyways, they bought so they still had the free version, the standard and premium. This is after they, you know, simplified everything down. So the pricing is now standard is $100 a month and not a no $100 A year $15 or 15 a month you pay a little bit more to do but per month premium is 500 a year or $65 a month. I'm actually tomorrow I'm probably going to buy the premium version. This version eight, right? Yes. New Version cool. Mainly because we have a lot of our customers are evil users. Yeah. And I need to make sure everything works in our upload interface with Eagle eight. Ready to confirm, have the Confirm? Plus, I need to update cuz I'm still on 7.3 or something like that. Yeah. So I actually have a copy of six, that on my old copy of six and then have a licensed copy of seven, and then we'll have eight installed on it. I probably should try to find a copy of five. Are we still getting five? I think I think we've seen five come in, like twice over the past two and a half years. Okay, so it's not super important, but it does happen. Yeah, it does happen. I probably should try to find a copy of five. I wonder if I can just ask Eagle. If I buy eight and say, Hey, can you give me five? Since probably no one buys it? I'd rather not have to get it from other sources. Sure. So on this page, where they announced it, right, they have a chart that's like they're trying to justify going to the subscription model. And it's like, well, a coffee is like 250 a day and ours is only, you know, 50 cents. And the funny thing about that though? Over the Air. The funny thing is though, is they say it says 50 cents. When you do the math, it's actually $1.50 Oh, but the graph where the bar is is correct. It's just the number beside it is wrong. Oh, that's shady. Yeah, that's really shady. Can't be doing. here's the here's the question that I'm wanting to know. Cares. Well, first of all, where do you can Whoo. What? You know, hipster guy buys a 250 coffee. That's like the coffee you get at like 711 I mean, I think last time I went to Starbucks, it was like seven bucks. Well, I mean, did you get like a gallon of coffee or something like that? Event? A whatever size that is the Mondo No, I think that's a that's that's the big one. No, that's Grande. Nope, Grande is in the middle venti. They won. Yeah. The call is the small the tall is the small. Grande is in the middle. Yeah. It's like Mac sizing schemes. Just Just think of it as fat fatter and fattest. Yeah, exactly. Yeah, that works. So okay, I'm curious, can you turn this subscription on and off whenever you want? I bet you if you had the monthly one, probably okay. But I'm going to bet you you quote log in it's probably works like the Adobe, you know, Premier suite, or wherever it is, where you have to log into their server to use this stuff. Which is kind of annoying if you're like an airport. I mean, I actually like to route boards when I'm on an airplane. And the fact that ego would have to phone home to boot up, that'd be kind of annoying. Okay, I'm thinking, I'm thinking et phone home right now. Well, I mean, it's got a phone to the eagle server, right? So they gave me an offline feature like Steam does, you can click, I want to go offline for the next X hours. And so that when you go to the land, you know, there are people that still go and bring their computers places and play video games, right? People still land. I see. I was asking that question for like the contract guys who need Eagle for a month? And then they don't need it for four months? And then they need it again for a month. Yeah, actually, this would work out for
Host 3 28:35
Them. Okay, that is so that's actually great. Instead of having to plunk down 1500 bucks you in 65 bucks, whenever you whenever you need it, and then you have a killer copy. So I say most guys are probably using Altium though. And I wish oh my gosh, I wish Altium had this kind of pay structure. Yeah, for their thing because I would totally drop. I you know, 120 bucks this month. Give me every package Altium has, I'll finish my design and then take it all away and I'll be happy. But they want that $15,000 Yeah, 15,001 time upfront by and then $400,000 a year worth of maintenance on their package. They're really proud of their stuff. And dammit I like it. Alright, topic three LEDs categorized by product bin. I did not know this way what so I knew that CPUs and like big processors. When you go on like Newegg or Amazon to buy a processor, the faster processors are binned at that level. So usually they're closer in on the die when they make a wafer, right. So they have less bad transistors basically. And then the other ones like the like an AI five, where they basically just disable some of the yours might lasering and shut. Yeah. But those on the outside of the wafer, but they test them all. So they try to get as many I sevens and I fives and then down the line I force. Um, but so they been the dyes that way. Yeah, they apparently been LEDs the same way. I didn't know that mean, either. And I, a customer was asking, like, you know, what does this mean? Because he was using these LEDs by Lumi. And he was trying to figure out what, what are been numbers? Because like, he doesn't know it. And it's actually in the Part Number. By the way, These part numbers are ridiculous. l 130. Dash 6580002011001. What does that mean? That sounds like an internal part number that they're just like, you know, screw it. Let's just use that sounds like there's like actually, like four or five of these numbers are been numbers in different bins, and they actually test each LED. So what is what is the different been mean in terms of the performance, luminosity, color spectrum angle? No angle seems to be not in there. But it's mainly to color mainly for white LEDs. Winds are really hard to make. Yeah, the white LEDs are very, very hard to make. In a very specific because people will. People like us don't really care a white LEDs white LED, right? But when you make a LED display, yes. For the backlighting, you need everything to be within a certain percentage. Or you have one corners yellow and one color is slightly blue. You don't want hotspots or anything. Yeah, yeah. And so that's what they use the binning for. So you can get all your product in the same bin. Interesting. Yeah. And so digit key actually has a really cool tech article, I guess, called decoding led been labels injured. And they talked about, like, why this is the case, basically, it's really hard to make consistent pin end zones on the LEDs, when they're, you know, laying down the engro in the crystal. Yep. And so you will have some varying thicknesses there. And then you have some varying thicknesses on like, actually, you know, putting the the encapsulation on all that affects it. So that's why LEDs are kind of expensive, because the Ollie's the good ones, right? Because they test them all. And Bin them. That makes sense. They're really cheap ones. They probably just chuck it in the bin. This is red enough. Red enough. Yeah. And it's writing enough. Yeah, yeah. Yeah, well, getting a specific wavelength is way harder than you think it is. Yeah. If you even look at like the band diagrams, red is one of the easier ones, right? Red was one of the first LEDs, right? And it also takes the least amount of voltage. I think a red one's closer to like one volt, for voltage, whereas like a blue can be up in like 2.4 volt range. Hammering or getting precision on the on the wavelength is super hard. Because it there's a lot of parameters that you have to hit spot on. When you're growing your crystal. Not an easy thing. Yep. That's really cool. I
Host 3 33:18
Didn't do that in college. I did. I wish I was able to do that. I need you know what I need to bring it in. So at a&m, this, this was the one class that made all of college feel worthwhile. There's always that one class. Yeah, well, and this one, okay, so it was my senior year, and I took a silicon fabrication class, and we got to go, we a&m has a silicon fab in one of their building. Well, they have a couple, but they have one that's for undergrads. And it's terrible machinery from the 70s and stuff like that. But regardless, it's a full room that's a full fab. And the whole, like, you're wearing the Tyvek suits, and the yellow lights and all this stuff. And we got to make our own silicone die. Chips, basically. And they were just a handful of resistors a handful of caps. We made some moss FETs and stuff. We got to do all top to bottom, and it was amazing. You have pictures. I have the chip. Oh, we got to take pictures tomorrow. Yeah, I will. I will bring it in, at the beach. So we made we made our own wafers. And I think there's 150 chips on my wafer. And at the middle of every single one of them in metal is the a&m logo. That's like half a million. photoshopped that part out. Oh, come on. Uh, Justin, our operations manager shows up today and he's like, I got something for you. And he bought muscle milk because he kind of he drinks that crap. But he bought muscle milk. And it's ut Muscle Milk and I was I was like, why is it branded that way? Because you're disappointed douchebags. It totally makes sense. I was like yeah, no Of course, UT would have their own branded orange. Yeah, of course it was, it was like this really nasty brown burnt orange color.
Host 1 35:07
And it's pretty gross. So that's that I'll bring the chip in, we'll take some pictures out
Host 3 35:15
Of that nice microscope. Yeah, what we can do is we can take the borrower lens off, so we can actually get 70x magnification on and we'll be able to see the ATM logo with that. Sweet. It'll be cool. Okay, last topic. So this is for topics for RFO Ooh, this is something new we're gonna start doing is we want to start having kind of like discussion topics on PCB assembly and design. So the first topic I have is, or for today is mounting holes on PCBs and what to look out for. Basically, the idea is we'll talk about this topic. And then what comes out of this, I'll write into an article. And so I can put it on the blog. And basically, we're writing the article for me automatically.
Host 1 36:04
Two birds one stone that hey, awesome. Sounds great. So mounting holes on a PCB, what to look out for?
Host 3 36:11
Yes, I'm making sure Well, first of all, I think the most important thing is to pick a fastener first. Right? Yeah, because picking the fastener. That way, you know how much clearance you need to put her on the head. And then how much clearance you need in your your hole. Because if you make it too tight, you're sorry, you're basically have to thread into the FR four. And you're actually probably splinter and crack the FR. Four, I was just about to say fr four does not like to be threaded. No, it is not a really forgiving material. Yeah. So when when I first read this, the very first thing that came to mind is actually the way that dip trace handles mounting holes. And I love the way they do. Because when you place a mounting hole, it gives you two parameters. One is the hole. And one is the head. Ah, yeah, it's not like that an eagle. Right? You have to draw both separately. Yeah, and I love it. What's great about it, too, is it's, you can make the whole parameter larger than the head parameter. And it just makes it a hole at that point. Gotcha. It doesn't make any keep outs or anything like that. But when you go and pick like a 440 screw or something like that, pick the major diameter, and then pick the head diameter, put those in a dip trace. And then you know where not to route. Yep. I was pick the the major diameter thread plus, like 20 mils. Yeah, just so it's has a little bit of Oh, yeah, yeah, slop in there. Of course. Um, and then I always pick the head diameter. And then plus, usually about 15 mils of I can on the on the radius actually. So you have extra space, right. And then, depending on what you want this to do, if you're mounting it to a metal chassis, and you need to ground the chassis, yeah, plate the hole, you can plate the hole, and you can actually, you know, pull solder mask around it. And then when you crank that screw in your actual ground, you're bored out to the chassis. So when I do that on a PCB, I don't use a mounting hole, I actually use a pad. Gotcha. Because because the way the EDA tool handles, it is the same thing. Yeah, mounting hole is just a pad without copper. Yep. And what I usually do too, is I take if that if that's my purpose of that, to ground out that, that chassis to that thread, or that mounting hole is I'll actually have the fab put paste on that hole. So have it marked as paste. Yeah, and so it'll get flowed. And so when you actually put the screw in Oh, does it digs in and actually gives you more contact and resist corrosion better. And actually, if the if the solder is already there, in your situation, if you really felt like it, you could heat up the screw and solder it to there, if you want it to go, that would be terrible to take apart later. Oh, it'd be It'd be terrible. But if it's a permanent thing, you know, vibration would not affect that. And then another thing people don't look out for is what tool you're going to use to install this screw. Because if it's a Phillips head, or flat head, you're fine because usually your screw is or your your diameter of your screwdriver is either equal or smaller than your head of your screw. But if you're using a hex, your hex is bigger than the head. And so you got to watch out for if you put a giant capacitor next to it, or connector, and then you just can't get your tool in there at that point. And personally, I really like hex fasteners for PCBs because a lot of times you do have to feed it, you know next to a connector so you can't really get your finger in there. And most hex tools hold the fastener better, as you know dropping it into the the chassis. Sure. Cool and something kind of to rewind a little bit. I don't think it's, there's any way we can make it more important to consider the head of your fastener. Yeah. Because if you run a trace underneath the head of your fastener, you cannot be sure if once you torque down, if it's not crashing the trace, or if it didn't scrape off solder mask and make contact, you don't turn on traces to that's, that's true. Because actually, that's a big deal with iPhones, where people do iPhone repairs, and there's like one screw, that's like, point two millimeters shorter. It's, like, half a thread shorter than all the other screws. Oh, and it's there for a reason. It's there in that one spot for a reason. And if you use a, if you use that shorter screws somewhere else, and install it, you will actually crush at second you know, it's like a eight layer board. Yeah, right. It will actually crush and break internal layers on your repair. Ooh. And there's actually some really cool videos on YouTube on repairing those internal layer traces. Oh, geez. Yeah, scraping it all away, and
Host 3 41:08
Not just making contact somewhere else on the board. Wow, scraping the web layers, right. And rebuilding traces with with a nanowire, just throw the iPhone away and go get a real phone. And then, the other really important thing I think about is board flex. There's not too much about mounting holes, but it's what you're mounting into. Yep. And how much torque you put on that fastener into the hole. And the main thing to look out for is because if you have too much flex, you can break solder joints. Yep, on find pitch leads balls on BGA. Those aren't really too big of a problem. And same thing with internal traces and outer traces. You have to flex the board a lot to get those to break. But the main thing to look out for is ceramic capacitors, they do crap. And they will they will fracture if you put them if you put a ceramic cap too close to a mounting hole. And then you will have failures. They will crack and they will failure. And they fail shorts. Usually in that case. Yep. I've had experience with products in the past where we use ferrite beads for EMF rejection seed stuff, and you flex the board. Those will crack open. It's game over at that point. Yeah. But your signal just doesn't go through. Right. Right. Right. And I think I think the the overall I rule of thumb is no flex is acceptable. Yeah, just like consider that. Yep. And that's typically that's not that hard to design around.
Host 1 42:45
No, no, you have to make sure you're, you know, I wonder what the IPC standard for board Flex is.
Host 3 42:53
I have that document. I can I can pull that we should look that up. You know, why edit or when I do the podcast notes tonight for this. I'll make sure to make a note to get that from you tomorrow. It would be great if IPC just has a No it's like no flex. No. Cool, cool. So um, if y'all have any more questions like that on PCB design and assembly and blah, blah, blah, blah. Give us a tweet, send us an email, whatever. Yeah. And we will talk about it. I'm at macro underscore ninja near and I'm at Longhorn engineer with no O's. Alright, and you can just go to podcast notes and the links are there. Great. Awesome. Well, that was a the Mac fab engineering podcast episode number 51. We were your host, Stephen Craig and Parker Dohmen. Take it easy, guys later
Transcribed by https://otter.ai