 And welcome to Desk of Lady Eta. Hey, everybody. Welcome. Oh, it's cool. I've got this green bandaid on its block. Welcome to your transparent open source, as always, Lady Eta. Sorry. So it's Desk of Lady Eta time. I know it's Saturday night. Tomorrow we want to, well, we're going to go see dinner with a friend. We're going to talk about electronics and engineering with one of Lamor's MIT friends, which is exactly what we wanted to do for the last 18 months. So we're going to do that. We're going to do that. And after I drink all that shi-chu and eat all that bibimbap, I don't want to come back here and try to do videos. So we're going to do it Saturday night instead, which is fine. I'm much more focused and not drunk right now. You're on it. Let's do this. OK, so you've got a couple of things going on Desk of Lady Eta. First off, is there any news or updates you want to get? This Wednesday, JP'll be hosting Show & Tell. We have a normal Ask an Engineer. We have our shows on Tuesdays, Thursdays, and Fridays as well. And then we have this special Saturday one. So over the next 10 weeks, just because of the holidays and more, we'll probably be moving stuff around. Lady Eta and I are doing some volunteer work during the week of Thanksgiving. And then we're also visiting an Eta for team member who's in the hospital on Thanksgiving Day. So things are going to be a little weird, but we will continue to publish, publish, publish, share, share, share. Take it away, Lady Eta. OK, cool. All right, so this last week, I'm back trying to get some more hardware done in a run up to the holidays. And the Feather ESP32 S2, I finally, it's like a design from like a year ago, but we finally got the modules a couple of months ago, the ones that have both flash and PSRAM. I didn't really want to release it until I got the PSRAM modules. I guess I could have, but I don't know, whatever. It doesn't matter. So you get the PSRAM cable modules in. And so we want to go to the computer, a really fast show. They're out of stock at this moment. Actually, it says in stock, but I don't believe it. Really? I guess we have some of the Feathers in stock, which I didn't realize. The ones without the BME 280 sensor. And then we have two versions. Yeah, that's pretty remarkable. Folks, you should probably pick up some. I mean, like, where I'm in. I don't know if that's true. That seems a little unlikely. It was out of stock. Maybe somebody was walking today? I don't know. No? OK, well, anyways, maybe an allocation got undone. But so you get the ESP32S2 Feather and the one with the BME 280 sensor. I kind of made two versions of this. It's one-foot, but it's one PCB design. And basically, whether we place the sensor or not, there's a price difference. And I figured some people care about the price difference. They want it cheaper or they don't. That said, I kind of like the version with the BME 280 sensor, because it's kind of an all-in-one environmental Wi-Fi sensing thing. And I think even though this wasn't designed for ESP home or remote node stuff, I think there's enough people that do those kinds of projects that it would be neat to have a version that had a sensor built in. And then I could also make a version with the BME 680, which also has a gas sensor. And they have an AQI air quality algorithm that's available for the express if it's a closed source binary blob, but it's available for the express if 10 silica chip set. So if people remember from like a year ago, I designed three versions of this feather, actually. So this one, a version with a TFT, and then a version with a TFT on the back. And ironically, I never actually put together the version of the one with the TFT on the front till now. So let's go to the overhead. And I can show the different versions. So this is the version without the BME 260. This is the normal feather. And it's got the BME 280 spot here, but it's not placed. And then here's the version that does have it placed. It's basically, we just program the pick and place whether or not to have that sensor pick and placed on. And then this is the other product that we put in the store. So you can see it's displaying temperature, pressure, and humidity. So handy. It's got basically the top three environmental sensors people want. So then the other version is this version, which has the very cute TFTs, which it's funny for like a decade. I was like, oh, man, I can't wait to have little TFTs basically just like those little OLEDs. And they finally became available. I don't know. I think these are used primarily for smartwatch bracelet workout things, like the heart rate monitor slash step counter thing. So this is the color TFT version. But I love this TFT. Because first off, it fits right in between the feathers. So you can see, it fits very beautifully. It's 240 by 135. So it's a good number of pixels. It's basically equivalent to the 1.8 inch TFT that was one of the first TFTs we've ever stopped. It's product number 300. But it's tiny, and it's IPS. So it looks good. And so this is a simple demo. So we did Arduino testing last week. And then this week we're doing, we did some circuit Python testing. So this is a, you can kind of barely see it, but it's the Blinka with a star. And then it goes and gets our GitHub number of stars on the circuit Python repo. Why this demo? Because it's not the Bitcoin demo that people apparently think we're destroying the planet by doing. So we don't do the Bitcoin demo anymore. So here's the thing, everybody. We've been looking for a really easy thing that everyone would recognize and say, oh, that's live data. And sometimes new technologies come along and all these crypto things came along. And it was really easy to just be like, oh, what's the price? And it has a date. And there's like, you could look back at time. And it changes rapidly, which was another really good thing about it. But here's what we've learned is there is no nuances anymore. Either you're, oh, we'll have fun being poor, you're not into crypto, or you're burning down the planet. And what's happened is people on Twitter has targeted and harassed our team. And so basically, we're just like, well, let's just not have this on social media. But let's find something. Well, let's find something pretty good. And what's cool is since we stopped doing that demo, people don't use Bitcoin anymore. So it's actually worked out. But the thing is, I just want everyone to know, we'll always do the right thing. And we'll always try to make sure we don't polarize things. So we're not going to have that type of thing on any of the social media things. But this, in particular, is fine anyways. So GitHub Star is a community thing. And it's a nice thing. I wish there was no API needed weather thing, but it doesn't exist. Yeah, that would be, of course, ideal, but there isn't any. OK, so this is a number of stars for CircuitPython repo, and it updates every minute. One thing that I noticed when I first put together this board definition, I actually copied the TFT definition from the TTGo, which is a other ESP32S2 board that has the same TFT. And I was like, OK, great. I'm just going to take that initialization and change the pinouts to match. And one thing I noticed is, you see how the TFT is really slow to update? Like it has this really weird slow wipe refresh. So that's from when you draw bitmaps in CircuitPython, especially on this board where the flash memory is shared with the program memory, which is like all the memory is basically shared on one chip. Fetching the data from the bitmap on the QSPY, if the TFT is rotated, it doesn't redraw linearly. It has to access the BMP out of order, because it rotates it. And so it scans the BMP out of order, just jumps around to get the scan line of that BMP for that location. Whereas if you, and it's not linear, it's 90 degrees. So it's accessing each pixel of the file separately. Whereas if the TFT is unrotated, it does the right math so that it can read the BMP linearly. Like BMP files, if you've ever opened them, they have the data like linearly inside it. And so you can seek to get the pixel data you need. But it's ideal if you don't have to seek if you can just start from the beginning and read the data out. So I was kind of like, oh, how to fix this? And I thought it would be worth showing how to do that. So if we go to Circuit. Yeah, I can show the poor quest. So under, let's see, it's under ports. Suppressive boards. OK, so here, I think it's under board.c. So there's this kind of thing with Circuit Python. What we do is when the TFT is built in, we have to initialize it before anything else. And so we actually have to have all the initialization data needed for setting up the TFT and drawing to it like in the C code. We can't load a separate driver. So you can always, if you want to have a driver that initializes the display using display, but it's kind of cute when it comes up automatically. So here we have the display in its sequence. And the thing that you kind of end up having to mess with the most is the mad control register, which is memory address. I think MAD is memory address, memory addressing of display control register. And that's 36. So 36 is, and this is true across almost every TFT display. So almost every TFT display uses the MIPI standard commands, which is why sometimes if you're initializing a display, people are like, oh, I initialized this ST7789 with I-Line 9341 code, and it came up. And sometimes it actually comes up, and it's rotated or it's weird colors, but you actually get something on there is because the commands are almost all the same for getting out of sleep, for setting the gamma, for changing the orientation and stuff. So the MAD control registers what you do to twist around the display and determine what is orientation, the native orientation. And what's really nice is that they'll let you, almost every TFT lets you set this register to say not only which corner is it, but which way it's flipped. MAD control also sometimes changes the RGB ordering. So sometimes you'll get a display. You'll see I actually kind of messed it up when I made the PR. I ended up swapping the red and green or something. And so that register kind of has a lot going on in it, where it's for 36. But the hint that it was not oriented correctly is, oh, here, this is actually the correct version. If I go to history, OK, so this is the diff. But if you go down here, the rotation was set at 90 before. And by having the native rotation be 90, that's why the TFT, when it displays bitmaps, it gets very confused. Because it rotates the display, then it has to un-rotate the BNP. And basically, all the math gets a little messy. So when I did the PR, I changed the init code, basically from, I think it was 0, 0. And I set it to 0, 8, or 6, or whatever. And you can look in the datasheet for which way it is. Although I'll say, because every time I bring up a TFT, I'm always ending up messing with the math control register. And the only hint I have is just sit there or just try. Like just flip the bits until it comes into orientation you want. So the good news is that I did fix that. And then I guess I went to go to the red. Yeah. Oh, another nice thing is the Tina UF2 bootloader that we have. It's not easy to see, of course, but it tells you like. This is nice. It has a little bootloader symbol. So you know it's like in the bootloader. So one of the things I really like is low cost electronics, running, scripting languages like Python, USB-C, Stemmic Connector, shows up as a USB drive, has a UI for the user, has a screen, has battery stuff. Like, this is like, this is what we've been working for. Yeah, it even says, like, download a UF2 and drag it on. So I feel like if you have a device with a TFT, I like it when, if in bootloader mode, it would come up. So this is the new rotated mad control. So the good news is that, like, I did fix one thing. Let me hit the reset button to get it to reset. So the good news is I fixed the speed. So you see it, like, draw the image immediately. It is fast. Wow. But I flipped the color so yellow is blue. So I inverted the color or something. So I have to go in and, like, again, I just have to mess with the MAD Control Register until I get it right. And that's, you know, every bit is, like, flip, rotate, RGB, GBR, whatever color. So it's very, very common. When you do a TFT, that's the kind of the register you end up sort of, like, poking at as much as possible. But if you're adding a TFT or circuit Python board, try to get the rotation to be, like, whatever you want the native rotation to be, have that, which is like, you know, I want it to be, I kind of like this, I sort of feel like feathers should have, you know, the USB on the left and the battery up. And then this is the legibility, you know, and the text shows up quite nicely. These are design choices. Design choices. And engineer makes. But this is, but just to be super clear, like, this is not the native, like this top corner is not the hardware native 0, 0. It's actually this way. 0, 0 is supposed to be here. So, you know, you're rotating it. Question, what size is the TFT? This is like 1.1 inches diagonal. But it's a nice display. IPS display. All right. What's next? OK, so speaking of, you know, one thing I wanted to talk about is these mini modules, because I wanted to, you know, people who are watching the show, a lot of them make hardware, so I wanted to give you guys a hint. So this ESP32 S2 module, again, I'd like it. I don't have a, I don't have a, and we're over. Super handy, hold on the ground. So there's like, you know, three sizes to ESP modules. So this is the war over. And this is the, you know, the largest version of the expressive modules. And these are kind of common because they have the chip, PSRAM and Flash. And sometimes there's no PSRAM, but there's, you know, spots for the PSRAM and the Flash. And so you can, you can get these customized with like any setup of PSRAM and Flash you want. If you order enough, Espressif will send them to you. And then there's the room modules, which look like this, which have the chip. And then they have either Flash or PSRAM. And you're like, well, you need to have Flash, right? But sometimes the Flash is built in. And then the mini, you see the mini modules actually like basically the same size, the mini module, if you line it up, it's pretty much the same size as if you just cut off this extra Flash chip. And this actually only has basically this circuitry on the right-hand side here, the chip and the passives and the crystal because it has the PSRAM and the Flash built in. Okay, why not rotate the BMP so the hardware can render it natively? Because when you open the BMP on your desktop, you want it to be like the image, you know, the stars are on the logos on the left. Someone's gonna have to rotate it. Someone has to rotate it. If you just do it natively, you only have to do it once and it's always like, it's elegant. It's like, it's exactly what you expect it to be. Because I think that people want to have a, you know, I feel like having a landscape view is better than a portrait view. But yeah, if you wanted to do portrait, portrait. I knew that too. All right, what's next? So this mini module is nice because it has the Flash and PSRAM built in. That's why I like it. That's why I'm using it because I really like the two megabytes of PSRAM. It makes IoT and memory not a problem because you can read message, JSON files, bitmap files, whatever, you know, and store them in RAM and you have two megabytes of RAM. It's so much that you barely even have to think about it. So if you're interested, this actually over here is not an S3. This is an S3. So the S3 is the next chip coming from Espressif. And this S3 is somewhat like the S2. It's again, the next generation of ESP32. But the S3 is a dual core and brings back the Bluetooth low energy support that was taken out in the S2. So it's like, you know, they had the ESP32, like super famous, dual core, Bluetooth, Wi-Fi can do everything, but no native USB. S2 took away the dual core, took away the Bluetooth. S3 bring that back. So the S3 is the closest thing to like, it's an ESP32, but with native USB, which is like, I think great because it supports teeny USB and it's wonderful. And I just noticed that on Digi-Key, if you search... You want me to go to that? Yeah, if you go to the, because I was actually like, what is the status of the ESP32? So the 32 S2 mini, you can actually get the version that doesn't have PSRAM here. Although I'll say this version, which is the four megabyte, the N4R2 means PSRAM to flash four megabytes. You know, they say they're gonna have some in stock soon. It says like, looks like, you know, they have a real coming soon and they have more coming in February. So luckily they're starting to make it into circulation. But the ESP32 S3, and you know, I can kind of tell that they're gonna be doing a lot of promotion with this chip. So I'm always talking about the NPI here. So there are some ESP32 were over, sorry, were room and mini modules. Is this time for great search? It's not, this is a secret. Oh, we're not gonna do great search right now? Well, no, we'll get in a second, but I wanted to give people like a hint because I can't just on the great search because this is gonna be gone by the time I refresh. Okay, so I get it. So right now, if people want this, you should go get it now. And then we're gonna do the great search because then we save that as another segment later. This is secret. Yeah, I don't want to talk about this. Oh yeah. All right, so, hey y'all, for the community, by the way, the community that watches this lately is awesome. These are some of the treats you get. Go get some right now. Go, go, go, go, go, go. Because there's gonna be none. Yeah, for sure. If you want a prototype, if you want to develop with the S3. What should they search for on the site to get to this? ESP32 S3. Yeah, I didn't want to put this on the great search because I felt like maybe I'll do it later when there's more in stock, but these are really engineering samples only. They're not, these are not for large scale use yet. And there's also- Go, go, go, go, go, go. Dev boards. Although I don't think, oh yeah. So they have the dev kit. Yeah, someone said the great shh. This is the dev kit I've got. So I recommend this one, it's got the dual USB. 351 is up. And they don't have any other dev kits. We don't know how people will be buying these and popping the chips off. You can't, I mean, you can use this and remove the room if you want, but they do have some more rooms in. Okay, anyway, so that's- So I'm gonna pretend that didn't happen in one of your search? It was not a secret secret, it just didn't happen. We were here. Yeah, so let's go to the great search. I'm gonna do that, ready? Yes. Let's go to this intro. Where? The great search brought to you by Digikey. You know what I'm saying? There you go, Digikey. Every single League of Lady Aida looks online at digikey.com and finds- Parts. The parts. That you can buy. And we call that the great search. What is this week's great search? Lady Aida. Okay, so this week's great search is kind of, you know, it's a two in one. So one, Pelolu, which is a friend company, they're in Nevada. They also do open source hardware and electronics. And they did a massive post about silicon shortages and lead times. And it's a great article, so go check it out on the Pelolu.com. And one of the things that they showed is like their stock levels for some chips, including MOSFETs. Yeah, so I just want to, I want to promote them. Also, please support Pelolu. Their stuff is awesome. Yeah, so every holiday season, every time they have a sale- And they sell it on Digikey too. We promote them. And I'll say this to our live viewers and everything. I really hope the maker companies and the electronic companies this holiday season maybe get together and cross promote each other because like AidaFruit doesn't have every single thing. And every year we post all the sales to other sites and everything. Pelolu and AidaFruit always do that together. And we try to get the spotlight on Pelolu. But you know, there's this thing that happened. Like we all used to be a community and was smaller when we first started doing open source hardware together like 15 years ago. And now everyone's a competitor and like knives are out and like there's people who don't even talk to each other anymore. I think given that we've survived the pandemic and not everyone did, but given that like we're here now, some of us did, maybe it's a good reset. So anyways, this is part of the great search is finding the goodness in each other. In addition to this part back to you Aida. You're searching for another good come soon. Their stuff is available on digikey.com as well. So you can purchase through them. But please support Pelolu. They do awesome robotics stuff. But I really liked they posted some really good information about their part shortages and how they're struggling. And they mentioned that even MOSFETs are hard to get. Yeah, it's like the Silicon shortage. Like I know that there was a blog post by Playdate by Panic and they were talking about how their STM32 F7 chip or H7 chip, whichever it is. It's like they got a lead time of two years. And I saw another company say, you know, we have an FPGA and it's some crowdfunding project and they're like, our FPGA is delayed also for like a year or two. But you know, those, and those are like the things you're popular because you're like, you hear about these chips and sensors being used in automotive. But we're seeing this too, even MOSFETs, like even the most like jelly bean of parts are getting hard to get or you order them and you're not getting them. And I always found that a little bit weird because I'm like, you know, if you make a, you know, if you make a Silicon wafer with MOSFETs on it, I mean, you're gonna get like hundreds of thousands of them per wafer. I mean, they're very simple. They're easy to fab, but it could be that that process is booked up. So one of the things that we actually were, this week I had to go and find an alternative for is for our prop maker featherwing it's a stock because we actually couldn't get, there's not a lot on here, but we couldn't get the MOSFET that's used with turning on the RGB LEDs. So this prop maker wing part of it. And you know, of course, wouldn't I design this? I was like, what's three and channel MOSFETs? What's the big deal? How could they ever not be available? But we have a little RGB LED driver and you can see this ultra high power LED. A lot of people who make, you know, sabers or props, they have a very bright LED. We just did a prop with it for Halloween. Then a pager did it and they used an LED and they said it compared to a new pixel actually kind of the point source created a nice effect. But to drive these LEDs, you actually have to use a very powerful and channel MOSFET with a good power supply because these LEDs can be three watts. They can be an amp per channel or even more, maybe an amp and a half for the red LED. So it's a sizable amount of current. So you want to drive it well. So here is the circuit design we had for the prop maker prop feather wing. So you see there's a n-channel FET and there's a light pull down, red, green, blue, very small little chokers just to keep it from, you know, running away thermally. And we spec the DMG3406. So let's go to the Digi-Key and this is the part I can't get. But let's look at this specs. GMG3406. So there's two versions available here but I think it's just the real size. It's how many is per reel. And yeah, one of the tricks I've done is, you know, I like to type in, you know, just a number here. If you're not getting a thing that pops up that tells you like the dates, it doesn't mean they're not gonna get them but it's kind of like, it fills me with an ease, you know what I mean? It's like what do you mean you don't even know when you're gonna get the next reel in? So that's when I think we even booked some and we haven't gotten them yet, but we went out and so we have to find an alternative. So, you know, when you're doing this, use the product attributes to select an alternative. So we're gonna guess it's gonna be a single MOSFET. It's gonna be an end channel. Now, I'm not gonna click active. This is a secret because I did it first and I didn't find a good alt. And then I was like, well, what if I click non-active and you'll see something came up? I want a MOSFET. Now for the drain to source voltage and the current and the drive voltage and the RDS on and the VGS. Again, I don't need it to be that precise number. I just need it to be around that number. So I'm not gonna check those off. Instead I'm going to then filter by groups because it's like, I just need 50 milli ohm about or less, right? And less is better. So I can always select anything under that amount. However, I do want it to be a SOP233 and I want it to be, of course, pick-and-place compatible. I want to use the same package and PCB because I've already got that designed. Okay, great. So I'll use so much. So 345 available. Now, even though I don't care about active, I do want it to be in stock. And that basically brings it down to 50. So there's not as many of these in stock month surprising. Okay, so next up. So the most important is that continuous current drain. Now again, I mentioned the LEDs, people can connect three to nine watt LEDs. So I want to be able to draw, it was like 3.6 amps. I want to have something at least as good. So I'm going to select 3.4 amps, which a little bit less, but still well within reason or above. And that gets me to 16 options. And then the next thing is the RDS on. So I do want to have the resistance be low. I mean, I really need to make sure the thing that's going to be challenging is if I have to dissipate a lot of heat through this transistor. So I want to reduce the RDS on because it's not really heat sunk and it's driving a lot of current. So I had 50 milli ohms before and I'll basically select 58 or under. So I'll give myself a little bit more option, but still. For the VGS on, I think, oh, let me see what it was. Gee, I think it was 1.7. Sorry, the VGS is two. I will say that I'm driving it from 3.3 volt logic. So I'm actually not concerned. Nothing, you know, that's the one thing I'm really not too worried about. The VGS, everything here is under 3.3. So that's good. So let's see what we've got for options. So there are actually a couple options available, which is always a really good feeling. Let's see if there's any other, the VGS max I don't care about and the gate charge I don't care about. So these are all pretty good. And then when I sorted down from stock, I actually got a lot of good options here. So looks like, you know, one thing that I thought was interesting is that there is a DMG3402. So this is a, you know, like a sister product to the 3406. And this one actually just has a slightly higher current. So it's actually a slight improvement and it has a lower VGS. So this would be a really good option. And there's also the AO3406. And again, I always kind of like it when there's like a competing company that makes a chip with the same subpart number. Cause it's like, they're going to match the specs pretty well. Like I'm not, I'm like, okay, clearly this was meant to be a drop in replacement. Even though it's not guaranteed, even though you should check the data sheet, it's kind of nice, right? So it's kind of like, when you go to the grocery store and they're like, oh, they don't have Dr. Pepper, but they have like Mr. Pib. And you're like, well, it's like a Mr. Doctor, PhD, whatever, it's close. So both, all of these are quite fine, but you know, these three, I would are going to say the top picks because they have, you know, I need a lot. They have over 40,000 in stock. The DMG3402, I would probably actually want to test it just to make sure it worked. But for drop in replacementness, the AO3406 is another really good option. And what's interesting is that this was a NRND, but they have 40,000 stock. And again, I don't really care. I just want to, I just have to get through the next couple months until that order that I placed for the DMG3406 comes in. So there's definitely going to be a lot of like, you know, pick, pick around, find the right component to match. But for, you know, MOSFETs, when you spec them, I'll say it's tricky because there's so many specifications. And some of them matter and some of them don't. Like because this isn't driving, you know, anything high speed, I don't worry about the gate capacitance so much. But that might matter to you. And again, like the voltage, the gate threshold doesn't matter. And I know the DMG3406 has worked really well. So even though there's a chip that has slightly better specs, I'm actually probably going to be safe and stick with these specs, just so I don't get surprised by something. Even if on paper something looks better, I've learned like, do try to stick to the thing that's closest to what you've got. And then change your specifications if you need to. And that's a great search. Where in the world is that part I need to check? Okay, I'm going to wrap it up. Question came in. Unrelated question, if you're taking them today. Yes, we are. Bought the SGP30 board recently and the LED on it is different than every other STEMAQT board. It's not red, not green. Is the on LED color difference intentional or relevant or perhaps simply the wrong slot for the SMD LED wheels chosen for the pick and place that day? It's some purpose because I believe that's a 1.8 volt power supply. And so it would not light up a green LED. So we picked it in color, which would read. And check at Khan's video to find out why you have to use a red LED if you have a lower voltage. All right, that's the show for tonight. Thank you everyone so much. Again, want to say a special thanks to everyone who's always in the desk of Lady Aida chats and more, you know, you're the reasons we do this because sometimes it's rough out there, but y'all are good. So we're going to see everyone next week. It might be Saturday, it might be Sunday, unknown because there's a lot going on. But that's a deal with desk of Lady Aida. It's hacker time. It's hacker time. It's hacker time. I don't know. And we very much appreciate it. And thank you everyone who, you know, wants to all pick up some in the store because we want to keep doing this. And, you know, we got some skills. Got to pay some bills. So we'll see everybody next week. Bye bye. Bye bye everybody.