 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 things to show off today. I thought, let's start with a Stemma Sunday. Do you wanna try going to my computer? Okay, 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, I squared C bus buffer with stuck bus recovery. Okay, that's got a long name. So this, folks maybe saw in the store we have the ISO 1540. It's a bus isolator for I squared C, so you can totally separate it, like isolated, electrically, bus and power. This is kind of like a friend to that. It's not isolated, but what it does is if you've ever had the experience of you have a board and you're hot 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 I squared C. But what this chip does, which is cool, is it separates the clock and data lines on both sides and it like pre-charges them and also makes sure that when you plug in the in, it doesn't, I'm sorry, 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. Okay, so I kind of like 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 at anyone here who's had this experience and knows how debilitating it is when like your clock lines get screwed up. Okay, 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 new pixel right there. And then on the bottom, the RP 2040, crystal, a bunch more passives, flash chip, probably four megabytes, maybe 16 megabytes I gotta decide. And all the, I know it's cast-related, 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 it's gonna 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 RP 2040. So I just got back the Reb A PCBs, like kind of like Monday or Tuesday, put together, showed it off on Wednesday and 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. So that's another Stemma Sunday. Thank you. Cutie pie. And then next up, I wanna do a little mail bag. Who doesn't love 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 gotta tell you, like these, this is like the apple of like nerdy engineer shit. Like they're so cool. Like they made this awesome. Let's see if there's an, I don't even remember if there's an on off switch or how this turns on. Kind of mystified always. Maybe you plug it and touch it. Maybe it's, maybe the battery has to be charged, but they make like these little smart tweezers that I love and they're also well known for their like smart screwdriver and like the TS80 soldering iron. So they love to put a little OLEDs and stuff and make like super smart little tools. And so what I love about this is I wanna do like hot plate at home, but like you don't wanna have a hot plate that could like burn down your house, right? Like every Amazon review for like a hot plate is like there's a bunch of five star, like this is the great hot plate and the other half are like one star burnt down my house, okay? Not good. So this mini hot plate preheater, hopefully I could be able to actually do some like a hot air, not just preheat for like hot air rework but actually maybe like solder paste and like melt a PCB. And so this is it. So the packaging is like Apple-esque too. Okay, so you've got this, I mean it's like ridiculous, right? Let me get 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 and like 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. It also comes with like a little Euro adapter and then of course we'll need a really thick cable. So thankfully, it looks like they included it. I just have to figure out how to open this. Ah! Okay, I think I'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. Okay. All right, so. It's already been dubbed the cutie pie of hot plates. Well, I mean, so the reason I brought the cutie pie out was because I actually wanted to see like, is this, would I be able to rework this? I was like, ah! Can't take it anymore. All right, so 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 bit more forward and then tilt it at an angle so. Yeah, I'll do that. All right, so I'm going to, yeah, because I want to show you the little OLED. Yeah, so then I'm going to move it forward a little bit. And then. This is like the Snyder cut. Yeah. Okay, is that in focus? It's good enough. It's good enough. Okay. 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. You know those little quail eggs sometimes. All right, so heating, heating, setting. Oh, they even tell you what to do. Okay, 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. I guess after it hits a certain temperature. Yeah. So it's green, now it's blue. Yeah, now it's like a bluish-whitish 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 melt. How does this actually work? I have no idea. Well, how is it getting so hot? What's going on? I mean, the current is going into 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, I think, ABS plastic requires it. So this has embedded in this top plate, which, of course, I totally can't touch anymore, is a little resistor going through it that's 0.01 ohms. Red? Yeah, because it's hot. Guys, I'm going to grab my tweezers real fast. And let's look. It's not quite melting, but I can smell. It's starting to smell like molten solder a little bit. And let's see. No. I'm only to sacrifice this board a little bit. All right, so it's at 2230. Oh yeah, oh my god. It's like actually melting. Look, I could remove a component and replace 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 STEMI QT board at a time. This is like, or a little coil 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 or not. 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 STEMI QT. I basically got these just so I can make STEMI QT boards at home. So to be fair, the Tricot, the Gemma, and the QT Pi, those are popular boards. Yeah. I don't want to grab any, because it's too 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, you saw, I just lifted this board. So this is perfect for, I'm going to try to get a little angle so you can see the, sorry, I'm moving, I'm moving, I'm moving. Yeah, I've said it before. 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 mail bag and school. Minware, 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 CircuitPython. It might be interesting for people who are CircuitPython 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. Okay, 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 CircuitPython example on RP2040. Thanks to a pull request by Jeffler and Phil B who worked on this last week. Bringing, I know I saw people using RGB matrices with the Pico in the CSDK, but check it, we now have it in CircuitPython. 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 text and animations and colors and you don't have to compile anything in C and it works, it even has tiling now. I only have one of these matrices. This is 32 by 64 LED Matrix and I only have one here at the Descalady ADA but we have support for tiling them. You can make a big square or a big sign if you wanted to. And the RP2040 has a tons of RAM so it's perfect for that use case because these displays use a lot of RAM because you have to write 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 Descalady ADA is gonna be, or 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... All right, the great search is brought to you by Digikey and Adafrit. This is where Lady ADA 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, Joanne, go 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. 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 ends, 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 inside. You use a common screwdriver, usually a flathead but 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 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, you know, an ampermore. You want to 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 like 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 screwed 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 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 because 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 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 get a bunch of three pin blocks and you slide them together. And learn 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 pin from one, three pin from the other, and it was a mess. Number of levels. So how many tiers you have? Basically, 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 photographing a little bit differently. But that's basically what I'm looking for. Next up, 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, sure. 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 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, I'll 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 you're voltage and current bound, use those to search. But for me, I'm not, because it's like this is five volts, four amps. No, 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 still have people to add some solder, but if it's poor to you, good time, 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. Doesn't know what I'm gonna 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 gonna be very similar, right? 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's totally your stylistic thing. So given that I have a lot of choices, I'm gonna 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 gonna pick the one that has 27,000 in stock. 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, 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 that part I need? Okay. All right, that's it. All right, any other last questions? Is the 5.0 millimeters sum 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 through hole 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, just the late eight or around late eight o'clock. It's like a necklace, like a very hot jewelry. Yeah, careful. Yeah, it's all in there. 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. Yeah. So your orders keep going, so please pick up something native or sorry, different.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.