 and welcome to Desk of Lady Aida. Hey everybody, and welcome to Desk of Lady Aida. It's me, Lady Aida, at my desk. We got a couple minutes worth of desk check-in. Phil, do you have any updates, like general problem? Yeah, can you point your mic in? Oh, sorry. Now, this Wednesday, how's that? Good, at three p.m. we have a hack chat. Let's go to hackaday.com, hackadayio, and check that out. Now, Pedro will be doing the show and tell, and then we gotta ask an engineer at p.m. GP's product pick of the week. He is on Tuesday, Thursday. GP's workshop, and then on Friday, Scott's deep dive, and Wednesday morning. I broke it. Yeah, cool. Sorry. It's okay now. No, it's even worse than this. There's a microphone issue here. And then what's happening right now, if you all hear water in the background, it's because there's a giant leak above our apartment. And this is like the second time or third time this has happened. But this time, we don't have to get two of every animal and prepare an arc, because we let the building know, because we just happened to be here last time we woke up and there was pieces of apartment falling on LaDiana. So let's kick off the show. I fixed it. Yeah, you did good. Okay, great. All you have to do is watch out for the leaks and more. And, but speaking of leaks, maybe we'll have a product leak. We'll see. Okay, let's go to the overhead. I got some fun products to throw at them. Not boring. I had the Cutie Pie, the backpack type things that I developed a while ago. So I've been testing the LiPo backpacks. I got a LiPo battery. And here I've got the, I've actually changed the design. So you can see this little red wire. I added a resistor divider to pin A2 so you can monitor the output from the battery or the input to the battery. Not the battery itself, but like the voltage after the diode because that means that you can detect when you're on USB power or when you're on LiPo power. It's not perfect, but like, you know, it's better because it's like there's a diode drop and it depends on how much current is being drawn. But you can do some rough estimation of whether the Cutie Pie is running on the LiPo as it is right now or if it's running on the battery as if the voltage is above like 4.2. That means it's not being charged. So that's cute. And then you've got the, you know, the on-off switch so I can turn it off and turn it back on. So that's kind of fun. So it's a little cute little add-on to the Cutie Pie. So I'm ordering those boards. I also got this, which I'm not gonna sell. I don't think it's kind of finicky, but this is a iSpy adapter. So it takes the iSpy FPC connector out. And I actually thought this would be useful for me because like I have like a new display I'm testing and I put an iSpy connector and that, you know, gives you power and ground and all the pins for the display in the SD card. So that when I plug this in hold on, with this cable, I can do like very quick tests of a display. And so, you know, I still test it with, you know, wiring up each pin on a Metro mini, but just for like quick, you know, like did I get the basics going? Or if I want to test code on a display and I don't want to like wire up the display, you know, it's a little bit like STEMI QT but for more complicated devices, like, you know, SPI displays and stuff. So, let's see if I can get to focus in. I think it doesn't like how bright it is. There you go. So this is just, you know, doing a little demo where it displays an image, a bitmap off of the SD onto the TFT and then it inverts the display back and forth so I know the communication is working. So there are two boards that I got. And then I also have the 5x5 NeoPixel, you know, shield thing and I didn't put that together yet. But actually while I was working on this, I ended up doing an, you know, an INA 228 design that I did a long time ago. I finally got to, I was like, I really needed something to monitor the battery going back and forth. It's just like, oh, an INA 219 is perfect. And then I looked all around here. It was like, it was like 11 o'clock at night. I didn't have one. And so I was like, well, you know, good incentive to put together the INA 228 prototype and I got that up and going. It's a very nice chip, unfortunately, you can't get it. So when the INA 228 is around, it's a 20-bit ADC power monitoring and it does coolant counting and it does current and wattage calculation. It's actually pretty, it's pretty sweet. So I did that. I'm also trying to crank through a bunch of designs. Ironically, because it's Chinese New Year, things are a little quieter for me, which means that I can like kind of sit down and just like get through a bunch of designs where I've like made the prototype but I actually have to finish it, right? Like it's not enough to design the PCB and order five prototypes. I have to like finish the design, test it, make sure to make any mistakes, write any code, penalize the PCB, order it, you know, all that stuff. And it doesn't take a long time, but it's like, it's not as shiny and fun. So one thing I did also was a couple of revisions. And one of these revisions is the DRV8. You can sort of see that this is buzzing here. It's a vibrational motor driver that uses I squared C which is quite nice. You know, it's great if you just want to like really quickly add some like effects to a buzzer. The DRV2605 does like double tap and like ramping for you. And it actually makes the buzzing feel kind of like more fun than just like on and off. Like it can do kind of effects. And it has, I think like a hundred different effects built in. So this is going to be STEMI QTFied which is wonderful. Trying to get through all of the designs for the last like 10 plus years and get them into STEMI QT format. And you know, I have to wait till I'm out and then for a couple designs, I'm going to keep the old one because it's the shape is so useful for people. Like they really want to design that break out into a PCB and they don't want it to change. And so, you know, I revised the ADS1015 which is a very, very popular and all digital converter over I squared C and they made it STEMI QT format. But I actually think I'm going to carry both styles because just so many people have designed in the old version. So that's that. And then, yeah, this TFT also, this is a nice like 1.9 TFT, it's very long and it's got this FPC connector but it's quite nice IPS display. So a lot of like new stuff is coming out and then we got a shipment of same D21s which I ordered like almost a year ago. And these are the E18s which I used for the Gemma, the Trinket M0 and all the Trinkies. And since, you know, I can now make Trinkies and get like basically like I was coming up with a bunch of Trinkies and then I had to stop because I couldn't get chips anymore. And instead of designing and not getting chips, I was like, well, I'll just, I'll just do something else and we'll get back to it later. So one of the ones that I started to design but didn't finish was the VFD Trinkie. So this is a IN3A, I think, yeah, so you can see even, sorry, IV3A. You can see the Russian text on the back. If you're made in the 80s, this is kind of cool like Russian retro technology. They're not as beautiful kind of as Nixie tubes. Nixie tubes have this really nice orange glow. VFDs have a blue glow. But here's what I think about VFDs. You can get them, they're less expensive and you don't need like 200 volts. You only need like 20 to 30 volts to drive them. They give you a nice blue glow. And so, you know, I figured out the pinout for these. I don't have my 30 volt power supply here on my desk. So check out the video that Phil posted on the YouTube where I show off the VFD display. I'm posting it tomorrow. Sorry, check it out tomorrow. Yeah, I did a clue of what it is on our social media channels and it's not the thing that they dropped into NEO or at the time, this is for Anderson to bug him. But it looks pretty close though. Video comes out tomorrow. Yeah. So I, so check that out. I'll just Google for VFD tubes. You used to stock a display called the Ice Tube but then I couldn't get the tubes for a reasonable price. Like when I first came out with the design it could get 1,000 tubes for like $2 a piece and it was great for a kit. And then the price went up to 30 bucks a piece. Or you know, they were a little bit expensive. It was like $5 a piece but there just weren't thousands of it anymore. So we ended up stopping making the kit. But this little tube is cute and small. It's only a single digit. So I thought I would design a trinket. So let's... Just on a slide note, there was a mean guy that would send us nasty emails and stuff and say, you're using up all the tubes, you shouldn't use the tubes. My opinion about this is, what are you saving them for? Yeah. What are you waiting for? He was worried that these tubes would be put to a good use. They were being used. Yeah. No, he was worried they would actually be used. And so I didn't really like that but I'm glad that we might have another thing for people to check out. It's cool technology. And this is a nod to the past so we can build cool things in the future. Yes. And we're not gonna make you a thousand of these trinkets. They're not forever trinkets. Yes. They're a limited edition, not forever trinkets. So let's go to the computer and I can show you the design. I don't think we'll say not forever trinkets when it come up with an acronym if that makes sense. Yeah, like something that's kind of catchy that people will like. I don't know. All right. Well, we're gonna talk about that called the Ice Tube Trinkie. Yeah. So this is the standard USB connection. You got the SAMD 21E, I like it because you don't need like one component to get this running like two capacitors and a button. And then here you can see this circular design of the VFD. So they actually use the Eagle CAD Make Circular because I had never used it before and I was like, well, they will actually place pads in a circular pattern. So it's like, this is my chance and yeah, I worked fine. What did you do before? Just like math, a lot of signing because I'm just the math. So the tube kind of comes out here and you saw it from the bottom and then I've got transistor driver. So you see here there's like one, two, three, four dual NPN transistors and then pull up resistors. And the reason you can do this instead of actually driving 20 volts in you use a pull up and then you pull down to disable it is the 20 to 30 volts is a signal. It's a biasing voltage. You don't need, it's not that powering current that's the heater. Like the heater is what's drawing like 20, 30 plus milliamps. The signal to the 20, 30 volts to signal the, each filament, sorry, each segment to be on is like maybe a milliamp or so. It's very, very little. And so you can use a pull up resistor. I'll probably need to use like one K pull ups but it's powered to USB and look, this is, I had to make it fit and this was the only way to make the design a reasonable size. So it's kind of like the, it's kind of like a key shaped, right? Some sides are like a key that's in your key chain. Does have a lot of circuitry cause you need a boost converter and I also have a transistor to turn on and off the filament. But what I did is I connected the enable pin of the boost converter. First off, I pulled it down low by default. I can't get this to my controller pin. So, you know, when it comes up the boost converters off and so those filaments aren't going to be on. So don't have to worry about that. And then that's our segments will be on and then when I'm ready, I'll set all the NPNs to be low or turn them on so that the filament voltages or the segment voltage is off. Sorry, yes, it's low, it's off. And then I'll turn on the boost converter and that way, you know, I don't end up like turning on all the filament segments all at once. And that should be fine except I keep saying filaments when I mean segments. And then this is each, you know, NPN I got eight NPNs, one for each segment. And this is what the, what it looks like. You know, you've got eight segments, A, B, C, D, E, F, G, and then dots, ground, the cathode, sorry, the grid voltage which is again that 20 volts. That's what activates the vacuum fluorescence. And then the cathode, which is the heater. And for that you need about, I think it's like 30 or 40 milliamps at one volt. If you can generate a volt, great. But if you don't want to, you know, you just treat it like, you know, an LED basically and you calculate, you back calculate based on a three volt power supply, what your choke resistor is, and that's fine. And I put it on a PNP to be able to disable it also to, you know, not have it on at first and then I can turn it on when I'm ready to light up. So I think this should work out. I mean, I did work with VFTs on the ice two clock, but it's been, it's been like a decade. So I'm gonna have to remember like all the details of it. But I think it should be okay. I got like 10 of these little tubes on hand and I'll send out this PCB. And, you know, you'll be able to do circuit pipe on VFT, it'll be kind of cute. Very fun. Okay. All right. Do you want to do the grid search? Yes. Is there any questions before we? Ever thought of some input feathers, optical isolating feather, voltage divider feather, maybe a 74 HCT 40 50 feather with up to 15 volt inputs or something for vehicles. Love me some feather. Yeah. I haven't thought of that. I mean, I think that's a good thing that, you know, community member who's experts, I don't have a vehicle. So it's like, if I made it, I wouldn't necessarily know how best to make it work. I did design a Ken feather wing. And then, you know, of course, the chip that I was using, the MCP 265 25, it's completely disappeared off the face of the earth. Like I was like about to buy a thousand and they're gone and they've been gone. And it's one of the ones where, you know, it's just not, maker chip is not making them right now. So it's kind of a bummer because like the code was ready and everything was ready. A few chips were like that. I designed to a pretty much ready to go. And then I had to sort of pivot. So the thing about VFTs is they're not making them anymore, but they've never been making them anymore. And so I don't have to worry about getting them in a year because they exist now or they'll exist never. That's it. All right. What are the odds someone will take advantage of the VFTs running out and figure out producing more? I think Russia is kind of busy right now invading Ukraine. Yeah, they'll be gonna make VFTs. I mean, not these tubes. They do make VFT displays, like the Noritake displays. They're expensive. They're hot. They look great. We used to stock them, but people weren't willing to pay $100 for a VFT and they've been slowly replaced with TFTs. So there are VFT makers, not for these, not for the tubes for plates. You can get them, but they're slowly but surely kind of ending. You can still see them on cash registers. I don't think they're making a ton of them with them anymore because again, they're much more expensive than LEDs or TFTs. They don't think you need something that bright, but that's where they're used. Well, what would be cool is you'll see us on Desk of Lady Eda and on our shows and you'll be able to get one of these while supplies last literally. Not forever. Not forever, Trinkie series. Sometimes people take the first letter of each thing and they do something, but I don't know. It's just a crazy idea. Okay, let's do the great search. Let's do the great search. The great search brought to you by Digikea and Adafruit every single week. Lady Eda uses her power of engineering to show you how to find things on digikea.com. It's a good thing to know how to do because things are harder to find now. In fact, one of the things that I was going to, I was going to show one of my favorite parts and then it's actually not available, so I'm gonna show how to find an alternative to this part. So let's go to the computer and I'll show what I am working on and what part I'm looking for. So I'm going to be driving a VFD display. VFD displays need 20 to 30 volts to bias the grid and each segment. And so I need 20 volts and my thing is running off of five volts. And here's the good news. The 20 to 30 volts, you don't need a lot of current. You only need about 10 milliamps or so, which is not a lot. It's just basically to kind of bias it. The current draw isn't high. It's just the voltage is high. And so if it was like six to 12 volts, six to 10 volts, I might use a switch cap converter because I'm powering this thing off of five and so I have five, I could double that to 10, but like 10 is not high enough and I don't want to get two switch cap converters. Switch cap converters are very inexpensive. They don't have a buzzing. They don't have an inductor and don't have a diode. So they're quite nice in general. And I'll use them when I need like five, six, you know, seven volts from three or five, but in this case, again, I need 20. So what I need is a boost converter. So my favorite is, you know, when I use a lot for OLEDs, also need a biasing voltage. Again, not for, they don't use a lot of current at that biasing voltage, but you need like five to 10 milliamps at, you know, 12 to 18 volts, depending on the style and color. So I kind of come up with a boost converter that I use a lot for all of these devices that need a little bit of a high voltage. And it's based off of the fan 5331. The nice thing about the fan 5331 is it's, it's kind of a nice generic boost converter. You do need a diode. It's not synchronous and you do need an inductor and you need a little resistor divider on the output to set the voltage, but it's a slot 23.5. These are very easy to place. They don't take up a lot of space. They're very easy to use. I've never had an issue. I've never really damaged one. They're not high current boost converters. They're very like dependable, simple ones, and there's an internal MOSFET that's good for, you know, one amp switching, which you don't need to use that. I think the frequency is almost a megahertz. So the high frequency ultra low cost, I think like 20, 30 cents, any easy use. So that's the good news, the bad news is, oh, and this is how I organize my projects. The bad news is the fan 331, at least when I checked earlier today, was not in stock and it's not in stock. It is a great little chip. Again, you know, it's like, you know, 50 cents in quantity, very easy to use, but it's not available. So let's find an alternative. Yeah, that's what we do. I'm gonna be doing this for the next year or so. Lots of alternative findings. Come to my new site, alt.parts. Altparts.com. So the thing that's important to us is we want it to be an active DC DC boost converter with an internal switch and one output. However, the voltage supply can vary, the voltage output, you know, 20 volts or so. The frequency is 1.65, we don't need that. And I really do want it to be a SOP 235. So let's see what comes up. And I actually, this is not the one I wanted. Hold on. Oh, right. So here's the thing about the fan 331. I just forgot to mention. So this actually categorized as an LED driver. So boost converters, you'll find them in both locations on Digi-Key. Some of them show up in LED drivers and some of them show up in DC DC boosts. So just be aware. In this particular case, there are a couple of alternatives, this LM series, which are probably fine and some microchip ones, but I wanted one that was kind of around the same price and also, you know, in stock. And I only think there's like, these are in stock and, you know, they're not too expensive to like $1, $1.50, but I wanted one that was cheaper. So I'm actually gonna go for, I'm gonna search for DC DC boost and that'll take me to a different category, switching regulators, not controllers. I want the regulators cause the regulators will have internal switches and they'll like regulate the voltage for you, whereas the controller is just like the PWM controller. Okay, so I want active and I want one output. I want it to be surface mount. So select that, bigger. And I want it to be that five SOT. So I'm gonna pick five T-SOT and then SOT 23.5. And I think, this is always confusing cause there's like lots of different names, but T-SOT 23.5 and then, yeah, I think that's good. I remember the part I found after to remember what it was and then I want it to be a positive step up with adjustable output because I wanna, you know, set it to 20 volts and that's usually not a default output. And then when I search down here, oh, and then I wanna make sure that the voltage, sorry, I forgot to mention, I want the voltage output to be at least 20 volts because I need to have that 20 volts bias. So I'm going to skip all the ones that are five, six volts output. And then everything else here looks okay. Right, so this actually is what ended up coming up. So I've never used this part before, but it's very promising. So the AP3012KTR, which has 120,000 volts in stock, which is kind of sweet. And the pricing is, you know, 15, 20 cents. So this is a adjustable boost. You can give it 2.6 volts to 16 volts in and you can set the output to be 1.25 to 29 volts. There's an internal 500 milliamp switch. Don't forget the switch volt, the switch current doesn't tell you the output. You can rough it as the output voltage divided by the input voltage divided by the switch tells you the current output. So if my input is three volts and my output is 30 volts, then the switch, that's, you know, that's a 10 times multiply, three to 30. The 500 milliamp switch, I have to divide that by 10 by like whatever the amount I'm boosting because it's like the switch is from the input, not the output side. So this will give me 50 milliamps output, which is still plenty, right? Even in worst case usage, although honestly I'm giving going to be five to 20 volts probably. So I can get like, you know, basically 50 to 100 milliamps out of this. It's a SOP 23. And then this is the pinout for the fan 331. So switch, ground, feedback, shutdown, VIN. And then this is the output for the K package of the AP3012, also switch, ground, feedback, shutdown, VIN. So this will be useful. I think there's another one of these. One second. There is the E and the G. Well, that's probably a temperature thing. Let's use the compare. Can I compare? I've never used the compare. Okay. So this one's a little more expensive. Step up. These look very similar. This is E versus G. It's probably like a percentage rating or something like one or two percent accuracy and maybe like the behavior when it latches up. So I'll look at what the difference between the East type and the G type is, but it's cheaper than the fan 5331. So I'm actually gonna pick up some of these and I might use them in some of my designs because like, if I can save 30 cents in this chip, like there's 120,000 stock, which means it's probably gonna like, sometimes it's like the more there's in stock, the more I trust it. So I think that this is a good pick. So I'm going to pick up some of these. AP3012 from Diodes Inc. I do like the AP2112. It's my favorite regulator. So it's gonna be my new favorite distributor. She do a segment in the future favorite regulator. And no, the AP2112 is like, is like pretty sweet. All right. Is that the great search? That's the great search. And that's a great search. Okay. I'm gonna do a couple of comments that came in and then we're gonna do a couple of questions. Some nice kudos on the great search segment. Really up my game when it comes to finding replacement and original parts for a lot of work projects. I feel that you must be great at the game. Connect four. It's true. Awesome searching. I find I learned a ton from these segments just from watching which perimeters like Diodes decides are important and not important. And it's cool to watch our narrow down to the best choice. Okay. So the question, this one came into discord. Yeah. Question for Lady Eda. Person's on mobile. So it'll be brief. Is there a reason there isn't a way to turn on a pattern of LEDs at full brightness off in the AW9523 library? I'm planning on writing one. And I'm wondering if there is a structural reason to do that or something dangerous to the chip I should be worried about. No, I think the way I wrote the library is just simplicity, which is you turn on each LED in a row. I don't think I set up so you can write all of them at once, but you can adapt the library. If necessary, there might be an output setter where you can set them. I mean, check the header. Like sometimes I have the ability to set like the entire register at once. It's just a little bit more dangerous, right? Because you're writing all of the pins. And most people, I like to make it so it's like you're only doing one thing at a time. Okay. And then next up, this isn't a question. It's kind of fun. This is why we do what we do. One of the reasons is from Jim, fun story today. Went to a friend's house to help her shovel out from the snowstorm yesterday. After her done, she pulled out an old floppy disk that she found in some 12 year old files that she asked, is there anything I could do with it? The answer is, yeah, you'll be able to do a lot of cool stuff with floppies and we'll have some projects more continuous day too. Hold tight, keep that safe. We have a lot of things that'll help everyone rediscover all sorts of things. Don't put it on your files. Don't put it on something magnetic, just hold on to it. All right. And then do you have a matching inductor you prefer? Now the inductor really is, you know, whatever you need. So I have a different inductor. I do have a simple 10 microfarad inductor, macro Henry inductor that I use for a lot of designs. It's like a simple surface mount one. But the inductors really do have to be tuned to whatever it is that you're using. So check the data sheet for the specs. I think one of the first great searches we did was how to spec an inductor. Yeah. Do you simulate your circuits first in like LT spice? No, but I'm also not doing analog stuff. Okay. Do you use PWM for LED lighting? Yes, you will. You have the good way to do it. Or constant current is preferable. Pick whichever one you can. Pick your poison. Okay. That looks like all the questions. Thank you, everybody. Thanks, everybody. So much. We'll keep you entertained throughout the week. Hopefully inspire you to share your projects, your work, your code with one another, help uplift one another and more. We do this every single week. We'll see everybody next week. We're going to hopefully not get too flooded here. I'm now looking at that. In our apartment, yeah. The bucket is, I took my trash can. From the desk of Lady Aida, we'll probably be buckets to collect some of the water. But we'll see everybody during the week and thank you so much for joining us and thank you for all your support. Keeping us going, visit Adafruit.com and pick up something that pays the bills for these skills. All right, everybody. Thanks, everybody. Bye-bye.