 And welcome to Desk of Lady Aida. Hey everybody, welcome to a Sunday smorgasbord desk of Lady Aida. We've been busy here at my desk. I got a whole bunch of stuff done this weekend. It's Chinese New Year, so happy to hear the ox to anyone who celebrates. I'm sure Chinatown here in New York was awesome, but we're staying home, staying safe. But let's kick it off. We've got a couple of things to show off today. I thought, let's start with a STEMMASunday. Do you want to try going to my computer? OK, so this is a really interesting chip. I thought once in a while I'd show off some hidden secret treasures from the chip vault. So this is a hot, swappable, ice-cold sea bus buffer with stuck bus recovery. OK, they've got a long name. So folks maybe saw in the store we have the ISO 1540. It's a bus isolator for ice-cold sea, so you can totally separate it, like isolated, electrically, bus and power. This is kind of like a front of that. It's not isolated, but what it does is if you've ever had the experience, if you have a board and you're plugging in chips, like semi-QT boards, you might notice that if you aren't careful, of course, it can jitter the clock and data lines, or even the power lines a little bit. And it can cause your bus to go into a weird state where the number of clocks isn't eight or nine, and it gets all weirded out and freaky. If you haven't experienced that, well, congratulations. But it's one of the things they don't like so much about ice-cold sea. But what this chip does, which is cool, is it separates the clock and data lines on both sides, and it precharges them and also makes sure that when you plug in the out, it doesn't affect the input until it's ready, and then it will connect the two when it's like the buses. Both sides are fully charged, and there's no activity going on. So this is a cool chip. So I did design a breakout for this. Let's see, where is it? I think it's under level shifters. Even though I know technically it's not a level shifter. So let's open this up just one second. So I kind of copied a little bit of the ISO 1540 design. It's got the separation. But I think it'll be really handy, especially when, look, anyone here who's had this experience knows how debilitating it is when your clock lines get screwed up. OK, so that's the Stemma Sunday. So now I thought, let's spend the rest of time before the great search on the overhead. And let's show some cool stuff here. So first up, so this is the QT Pi 2040. I showed this on the show, and I also went by a Scott stream to show it off. But this is exactly what you think it is. This is a Stemma QT board with the Stemma QT connector, two buttons, power supply, and a micro-nu-pixel right there. And then on the bottom, the RP2040 crystal bunch more passives, flash chip, probably four megabytes, maybe 16 megabytes I've got to decide. And I know it's cast-alated, but maybe people can make a cut out of the board. I don't know. Anyways, I think this could be kind of cool. Bill Binko asked us to make a little jumper for the power pin here, and I did. So hopefully this could be used for USB host as well. So yeah, what's really nice is that it's got all the same pin out and pin names as the Stemma QT, the Stemma 21. But of course, it's this awesomely powerful RP2040. So I just got back the Reb-A PCBs like Monday or Tuesday, put together, showed it off on Wednesday, and I'm doing my final tests on this. But I'm pretty much ready to send out this board, and I think people will dig it. So that's cool. That's another Stemma Sunday. Thank you, cutie pie. All right. And then next up, I want to do a little mail bag. Who doesn't love a mail bag? I got this in the mail today. So this is the most adorable hot plate ever. It's so cute. So this is by MiniWare. And I got to tell you, this is like the apple of nerdy engineer shit. They are so cool. They made this awesome, let's see if there's an on-off switch or how this turns on. Kind of mystified, always. Maybe you plug it in, touch it. Maybe the battery has to be charged. But they make these little smart tweezers that I love. And they're also well known for their smart screwdriver and the TS80 soldering iron. So they love to put little OLEDs and stuff and make super smart little tools. And so what I love about this is I want to do hot plate at home. But you don't want to have a hot plate that could burn down your house. Every Amazon review for a hot plate is like, there's a bunch of five-star. Like, this is a great hot plate. And the other half are like, one-star, burnt down my house. OK, not good. So this mini hot plate preheater, hopefully I could be able to actually do some hot air. Not just preheat for hot air rework, but actually maybe solder paste and melt a PCB. And so this is it. So the packaging is like Apple-esque too. OK, so you've got this. I mean, it's like ridiculous, right? Like, why do I keep this thing is? So this is the hot plate itself. So there's this like big metal thing and there's like a heating element, I guess, in here. And then for the adapter, it's a USB-C. You can't really read the text, but it says 20 volts, three and a half amps. This is like a really chunky. Power supply has come through like a little Euro adapter. And then, of course, we need a really thick cable. So thankfully, it looks like they included it. I just have to figure out how to open this. OK, oh yeah, they've got these really nice silicone cables. All right, so, I mean, do people want me to plug this in? Do you feel anyone saying plug it in? Well, yeah, I mean. OK. All right, so. It's already been dubbed a cutie pie of hot plates. I mean, so the reason I bought the cutie pie out was because I actually wanted to see, like, is this would I be able to, like, rework this? Can't take it anymore. All right, so let me. Let me try plugging this in. So, hold on, give me a second. I'm going to unplug this. I'm going to swing the camera around a little more forward and then tilt it at an angle. Yeah, I'll do that. All right, so I'm going to, yeah, because I want to, like, show you the little little leg. So then I'm going to move it forward a little bit and then. This is, like, the Snyder cut. Yeah. OK, is that in focus? It's good enough. It's good enough. OK. All right, so then I'm going to plug this in. Someone suggested you could fry a small egg on it. A very tiny egg. All right. Those little quail eggs sometimes. All right, so heating. Heating, setting. Oh, they even tell you what to do. OK, so press this button. All right, it's starting to heat up. Yeah, and it tells you it's, like, nine volts. Oh my god, it's, like, getting really warm. Yeah. Oh my god, it's, like, hot. All right, well, I'm going to put this board on just to see what happens. Well, what's going to happen? I don't know, the solder might melt. I don't see how hot it gets, basically. This is so cute. Oh, look, there's a little neopixel that changed color. That's after it hits a certain temperature. Yeah. So it's green, now it's blue. Yeah, now it's, like, a bluish-whiteish color. This thing is so cool. So I wanted to stop this in the shop. So I got one to test for myself. So it has to hit 240 degrees for this to be able to, like, melt. How does this actually work? I have no idea. Well, how is it getting so hot? Like, what's going on? The current is going into, like, a, basically, a resistor. It's definitely an electrical heating element. It's basically just, like, the hot plate on your 3D printer. The thing that keeps it warm when you want to do, like, I think ABS plastic requires it. So this has embedded in this top plate, which, of course, I totally can't touch anymore, is, like, a little resistor going through it that's, like, 0.01 ohms. Red. See, yeah, because it's hot. So I'm going to grab my tweezers real fast. And let's look. It's not quite melting, but I can smell. You know, it's starting to smell, like, molten solder a little bit. And let's see. I'm only to sacrifice this board a little bit. All right, so it's at 20, 230. Oh, yeah, oh my god. It's, like, actually melting. Look. I could remove a component. You did it. Wow. OK, so this is cool. So what's great about this is it's really hot. And so I'm going to turn this off. And I'll very carefully, of course, move it to red. But what's cool is this is perfect for me to make one stem of a QT board at a time. This is, like, or a little quail egg. So much success. I'm actually going to unplug it, because I actually don't know if this is, like. Yeah, I don't know if it matters if you let it go through its own cool-down process. Well, it's actually heating up, and I don't trust it. So I just unplugged it, which is another nice thing. So I'm going to very, very, very carefully move it away. A feather fit on that? No, a feather is this big. So it's not good for a feather, but it's very good for, like, a stem of QT. I basically got these just so I can make stem of QT boards at home. To be fair, the trinket, the gemma, and the QT pie, those are popular boards. Yeah. I don't want to grab any. It's very hot. I don't want to show any. I can see someone getting one of these and running boards with Osh Park, getting components. And it's, like, my first reflow. Yeah. Yeah, you saw, I just lifted this board. So this is perfect for, let me try to get a little angle so you can see the, oh, sorry, I'm moving, I'm moving, I'm moving. Yeah, I've said it before, like, if you're just getting started with electronics now, good for you. Because everything's available. Everything's available and everything's possible. Yeah, so now I know that this works. So now you know what I do. So people are like, how do you know when something is good to stock in the Adafruit shop? You just saw the process that I go through. Like, I get one, and I actually put it through its paces. Like, you know, if it's a soldering iron, I'll actually solder a kit together. If it's a hot plate like this or hot air, I'll actually use it to rework a board. So this is good to go. I love it. My gosh, so cute. Well, oh, luckily it was just cold enough it didn't damage itself. So, sweet, I'm going to put this away safely. I'll deal with it later. Nice. Okay, so that's approved. All right, so let's move on. So that was a mail bag. And it's good work. I love their stuff. Minware, they're just like my favorite. Okay, so, sorry, clean of time. So next up, I want to talk about a new pull request that just came in to Circuit Python. It might be interesting for people who are Circuit Python users with the RP2040. So, sorry, there's a lot going on here. Okay, so this over here, this is my RP2040 feather, hold on. This is my RP2040 feather and this is the Feather M4 RGB LED Matrix Featherwing. So you plug it in and boom, I'm running the Circuit Python example on RP2040. Thanks to a pull request by Jeffler and Phil B, who worked on this last week, bringing, you know, I saw people using RGB matrices with the Pico in the CSDK, but check it, you know, we now have it in Circuit Python. I had a little bit, a couple little bugs with it that I wanted to have them take a look at, but it does pretty much work. And what's cool is you can do like, you know, text and animations and colors and like, you don't have to compile anything in C and it works, it even has tiling now. Okay, I only have one of these matrices. This is 32 by 64 LED Matrix and I only have one here at the desk, LED ADA, but we have support for tiling them. You can make like a big square or like a big sign if you wanted to. And the RP2040 has a tons of RAM, so it's perfect for that use case because it can, you know, these displays use a lot of RAM because you have to direct the whole display constantly. We're not using PIO for this in case people are asking, hey, are you using PIO? Not yet, but we hope to add it. We want to just get it working first and optimize it later. Okay, so while I was doing this, I was like, man, I wonder what the desk and LED is gonna be or that the great search because we did this IDC cable before and then I realized, oh, you know what? Terminal blocks. People are always wondering how and what kind of terminal blocks we get. And so... The great search is brought to you by Digikey and I figured this is where Ladyida uses her powers of engineering to show you how to search for things on the Digikey site. Thanks Digikey for making this happen. All right, do you mind going into the overhead again real fast and I'll show what it is I'm gonna show. This is an RGB matrix and these matrices draw a lot of current. You know, they need two to four amps and so they have these big power connectors, these big molex connectors on the back for power. This is data only. You couldn't pass power over this, no way. Because it's amps, you need these big cables and on the end, what I do for this little driver board that the RGB matrix data plugs into is I have the power coming in through terminal blocks. Terminal blocks. Screw terminal blocks. So you see here. That you use a screwdriver, which of course I'm gonna have to get in a second. You use a common screwdriver, usually a flathead but a Phillips also for some. And you can loosen it to remove the cables and you can see there's like these holes that wire can go into. And we use this a lot. We use these on our motor drivers. So these are terminal blocks and then you'll want to measure your terminal block pitch, which is the distance center to center. So these are, I'll get this, these are 3.5 millimeter, sometimes respected inches, sometimes in millimeters, these are 3.5 millimeter. This one here is more, this is 5.08, also known as 0.2 inch pitch. And we use this a lot, whatever we need to pass a lot of current or control a lot of current or have some current connections like on our Cricut board. You know, we have a solenoid connected and we have a motor connected. These are things that are drawing an amp or more. You wanna have a solid connection. Yeah, you could use JSTs but a terminal block, any wire will work, right? And why not? That's great. So let's show how to get terminal blocks on the DigiKey site. So let's go to the computer. Okay, thank you. All right, so we're at DigiKey and here's the good news. You know, sometimes I'm like, ooh, there's like a trick to getting the terminal blocks searched. The terminal blocks searched, but sorry, the component, figuring out the name of the component to search for it. But in this case, terminal blocks is really easy. You just type in terminal block, super easy. And let me zoom in a little bit. Okay, so there's a lot. And the terminal blocks are used everywhere. There's like punch down type and there's like accessories and there's like, you can tell that there's like, there's power distribution ones. There's ones that are used for like fuse boxes. But we want the basic wire to board kind because it's a wire, screw it in and then attaches it to the board. So it's a great easy way of making any wire connect to a board. Okay, so next up let's, as usual, apply only active items. Just make it easy. And I want only Rojas compliant ones. And you know, I only want ones that are in stock right now. Okay, great. So the first thing is, well, first of all, you can always go down and look at some of like the cool weird, like this is an angled one that you can see. It's like not 90 degrees. There's ones with little push buttons instead of screws. So like the screw part is optional. They're all terminal blocks, but there's different ways of doing it. This one was also a little springy type. This one is a screw type, but it's also, you see this angled. I'm not a huge fan of the angle types, but like I see why people like them, right? So let's first count how many we need like positions. Cause actually that's the most important thing first. For this one, the feather wing for the RGB matrix, we need two pins. So let's search for that. So here's something also when you're searching for positions. So terminal blocks, it's not unusual to have them only available in two and three pin sizes, because you can slide them together and connect them. Like they're little like, like little snappy lego-y type things. I'm using the word lego-y completely against how the trademark is supposed to be used, but that's okay. We covered that in the last Ask Engineer. So you may, if you need something like a five pin block or like a 21 pin block, you might actually have to be, you might have to get a bunch of three pin blocks and you slide them together. And learned from my experience, every brand has a slightly different notch for sliding. You can't mix and match them. So you should pick one brand, one maker, and you stick to it because you can't mix and match them. But believe me, I've learned my lesson with that. I once got a mix of the two, paid from one, three pin from the other, and it was a mess. Number of levels. So how many tiers you have? Basically, you know, you have header and you have dual header and triple header. Same deal. How deep do you want the connections? In our case, we only want one because we just want a one by two header connector, that terminal block connector. Okay. Next up, the orientation, like that angle, right? How do you want it? Well, I want plain, I think horizontal with board, right? Sticking out this way. It's parallel to the board, not perpendicular. But again, they got these cool angles. Got the hit them angles. Check those out. So now we go down to these pictures and we're like, okay, yeah. This is what we're looking for. Right? This looks right. There's like tons of different ones. Like this one is kind of a cute angle here. This one, they're photographed a little bit differently. But that's basically what I'm looking for. Next step, two hole or surface mount. Oh, sorry, let's go to the pitch. So you'll see that there's a lot of different pitches in general, although not 100%. The pitch will determine the max amount of current and the min and max wire size. If you have very small wires, you'll need smaller pitches, but that also means you're carrying less current. So on one hand, the pitch determines like the physical size, but the physical size and the pitch also correlate with the amount of current. So you have to make sure so you sound like, okay, like true is true and false is false. If you have a current requirement, in my cases, my current limit is like two to four amps, which is not that much. But if you have a current limit, you might want to search by current. If you're like, look, I know that my robot needs 50 amps. You'd want to search by current for your connector that goes from the third. Yes, there's a question. Now that this was covered in part of searching for connectors, but what is the most accurate way to measure pitch on center? Ooh, good question. We actually have a guide on it. So how about I take a second and give you a tour of my caliper tutorial. Good job, Lady Aida, from a while ago. And I think measuring connector pitch, okay? I got it, okay? Check out that guy. Tell you how to do it. There you go. And so use that technique. Try to get me, but I got you. Okay, so, right. Current, if current's important to you, use that to determine the pitch. However, in my case, I have size requirements and so I'm going to do it by the other way around. So whichever is most important to you, if your voltage and current bound, use those to search. But for me, I'm not, because it's like, this is five volts, four amps. It's not that much. It's like, yeah. It's like barely even gonna make a difference. Only like the most tiniest pitches would not be able to carry that current. All right, something to watch out for. There's five and there's 508. Yeah, I know. But in general, the 508s, I found that the 3.5s and the 508s are the most common sizes. Those are the ones that we use the most. Five is when we have like a significant amount of current. Usually like four amps. 3.5 is like one amp or two amp is what we use it for. Although again, these can carry a lot more. Okay. So now you'll see, yeah. Like if you have a 508 millimeter pitch terminal block, the minimum is eight amps and the minimum voltage is 300 volts. So like you don't, this isn't a big deal. It's only if you are working with something that's again, like 40, 50 amps. All right. And then wire gauges. Again, the little, the connector, the way that the wire pokes in and you use a screwdriver to connect it. It'll affect your wire gauges. For me, it's not a big deal. I used to tell people to add some solder, but if it's poor to you, good time to check it out. There are surface mount ones. Let's see if I can load this 360. Oh, sorry. So you can see like the terminals here are surface mount type. It doesn't have what I want to use. Terminal blocks, you can get them surface mount but they really work best as through-hole. So get through-hole. All right, so great. So now we're actually down to like 73 product. That said, they're all going to be very similar, right? There's like, everyone makes, there's like, oh, there's like punchy type and there's like screw type this and there's green and there's blue. The color doesn't matter. The color is totally your stylistic thing. So given that I have a lot of choices, I'm going to do what I always do, which is sort by price. And then I don't necessarily pick the cheapest thing because there's only 24 in stock. Scary. I don't like that. I'm going to pick the one that has 27,000 stock. All right. That's like my heuristic. If they have 27,000 in stock now, I'm feeling pretty confident that this is a highly stocked item. I will not have problems getting this in the future. And remember, once you get one model of terminal block, if you want to fit them together and make larger ones, you have to stick to one brand. So, previous Lady Aida did write a guide about connector pitch, did not think a lot about the realization that the little nubbins on the side are different for each brand. So, here you can see the 360. So you can see that little notch here. And then it matches with this notch here. So you can see, yeah, zoom in. So you see that this notch, you can kind of see this little black triangle. They slid it together to make longer ones. And that's how you make more. And then the only other thing, you know, if you care, do you want Phillips or Flathead? Some people care. I actually personally prefer Flathead for these. So, this is why I like this particular one from Onshore Tech. But yeah, there's also ones that are Phillips head that people like as well. All right, and that's the great search. Now we found a wonderful, inexpensive terminal block for our RGB matrix feather wing. Where in the world is... Okay. All right, that's it. All right, any other last questions? Is the 5.0 millimeters some freedom of unit conversion? Unit conversion. Well, it's 5.08 millimeter pitch. That's the pitch between the contacts. So if you're matching to your PCB, you'll just have to make sure that you use like a footprint that has the pads, the foothold pads, 5.08 millimeter. Otherwise known as 0.2 inches apart. Are there screw terminal blocks for PCBs where you can screw by hand like the ones in audio speakers? Oh, like with thumb screws, I bet there are. Didn't cover it, this is great search, but maybe we're all in the future. Thumb screws is a popular thing. I'm sure there's easy ones. I will say that some people like the push connect type, although I find them to be tough to use. They're very firm, but they do exist. There's ones that don't require special tools. Okay. Okay, cool. And that's it for tonight. Special thanks to everyone who watched and asked questions. We're here for a single week, desk of Lady Eater, run Lady Eater, clock. It's like a necklace, like a very hot jewelry. Yeah, careful. Yeah, it's all in the hot. And thanks for supporting the company. We are still a woman-owned manufacturing company in the USA, as weird as that is, we're still doing this. So your orders keep it going. So please pick up something native for straighterford.com. Yes, thank you. That supports us and keeps us doing this thing, which we love to do. Yep. All right, thanks everybody. Have a great week.