 And welcome to Slady Aida. Hey everybody, and welcome to my desk. It's me, Lady Aida. Here where all the engineering gets done. And I've been working on a lot of hardware this week. A lot of prototypes came in. Some worked. Some didn't quite work. So maybe let's get started. Is there any updates or news? No, lots of big things going on all during the week. So stay tuned to our site, our blog, all the socials and more. And a special thanks to everyone who likes humor. We had a fun April Fool's joke. We did not merge with Ticketmaster. It is not Ticketfruit. We're not using that to sell Raspberry Pis. Lots of subtle humor in there. Thanks to the folks who got it and played along. It's only once a year. And then we posted a bunch of fun logos. You can check out our website. We did some fun art stuff. Let's kick it off. Let's go to the overhead. And let's... Sorry, I was just focusing the overhead. So the first board that I got in, the prototype that I tested this week, I got in... Hold on, let me just move this forward so I can get to it a little bit easier. Whoa, boards everywhere. So I'm making lots of Pi Cowbells. And those are boards that work with the Raspberry Pi Pico. So it's kind of a narrow thin board compared to the Feather. It's got two 20 pin connectors. So this is the Canbus Cowbell. And it uses the MCP2515 and the TJA1051 as a Can transceiver. And basically over SPI, you can communicate with any Canbus. So I tested this board with our Feather M4 Can. And this was sending messages. And this was receiving... Everything worked really well. A couple of things just, you know, I thought since I had a problem with my other board I talked about some of the things I found and how do I debug stuff. So obviously I do functionality test. I test every function that I want to. I test every pin that is exposed. So for example, there's an interrupt pin on the MCP, the one it receives a message, instead of polling the chip, it'll toggle interrupt pin. That's the example that tested that. I also tested the reset line. And that's when I realized that I had a mistake here. So this gray wire is because this pad should have been shorted to this pin. But in EagleCAD in particular, you know, this pin was labeled reset. And this was labeled bang reset. Like reset with a bar over it. And so they weren't actually connected as a net. So it was a typo mistake. So like, you know, I tested the reset functionality, realized that they weren't connected. So I jumpered it. And that kind of error is one where if there's like a missing pin connection and I verify by soldering a wire, you know, I don't usually reorder prototypes. I'm usually like ready to go into production. I tested the STEMI QT port, made sure like, you know, I plugged something into the X squared C, made sure it powered it worked. Test the button. There's a terminator jumper here. You do have to have at least one, ideally two terminators on a CAN bus of 120 ohms each. And I verified that when I cut this trace, this stopped working basically because they without the terminator, the can bus uses, I think either pull ups or pull down resistors. And so there's this, you know, the sawtooth wave instead of a square wave. And so data wasn't passing back and forth very nicely. I shorted the terminator, worked again. You know, verified low is low, high is high, you know, ground is ground. And then everything worked really well. And so like, you know, thankfully once in a while boards work on the first run, which is great. And in this case, that happened. And then I went to test the DVI VAL. So this one, this is, pardon me, I'm getting over cold. This is a lot like our DVI feather where there is a connector that can go to an HDMI display. It's only digital video, it's not audio or ethernet. And this is a mini DVI. And we actually talked about this board and this connector I think three weeks ago on the Great Searching Desk of Ladiator where I sourced this nice mini HDMI connector because a full-sized HDMI wouldn't fit. It's just too wide for the board. But the mini DVI works quite nicely and it's the same connector used on the Pi Zero. So like we already stocked the adapters and the cables and everything. And I put this together and I plugged it into an HDMI monitor and it had this really weird like flickering effect. Like you could see that there was video there but it would like immediately shut down and then try another display. It didn't work. And then I actually tried it with the video capture that we're using like right now on like Desk of Ladiator. I was like, oh, let me just plug it in. And that did work. And so I could see the video and I was like, well, something's working but I wasn't sure what. And I was like, well, is there like, you know, is it that Pico, right? Because the first thing you have to figure out is like, where's the error? I think with hardware it could be so many things, especially when there's an add-on board. So, you know, the first version that I put together had been with stacking headers. And I was like, well maybe the stacking headers are adding too much capacitance or something. So I went with you know, the shorter plug-together headers. And then I was like, well maybe there's other IO pins that are interfering or maybe the pins themselves for some reason don't work with DVI. I didn't actually test that pin collection. So what I did is I wired up a Pico to a DVI breakout and this worked great. So I was like, okay, those pins definitely work like my code is generating the signal on the right pins because it's like the same code. I just wired it the way it is on the schematic and this worked fine. So I knew it wasn't the pins and this has a ton of capacitance. Like this red board is in these wires even though they're fairly short. You know, if this is able to generate signal just fine, this PCB definitely should be. And this thing was weird because it kind of worked and that's actually kind of the toughest. Like when things kind of work it's like there's so many things that could be wrong. And then what else did I try? Well then I tried like, okay what other GPIO could be interfering. So I only soldered in the connectors that the ground and data connectors for the DVI. So like none of these other accessories would be interfering. And that still wasn't working. Although one time I plugged it in to my monitor and it worked okay. So I was like, okay, there's something like weird going on. And then you know, the last thing I was like, well, you know, I don't know if it's, you know, going to be very illuminating, but I thought let's probe each trace to make sure that's going from, you know, maybe the connectors loose or maybe this adapter. I tried different HDMI cables. And I probed them and I could tell that the signal was going through and then I plugged in an HDMI cable to the monitor to just make sure like the signal was still going through. Even though it's a very high speed signal, my scope is good enough. It's a one gigahertz scope. So you know, I could see the waveform, although adding the capacitance of the pro probably was kind of, you know, is going to make the signal a little bit more rounded. And I noticed when I plugged it in to the HDMI cable, the signal went short. It shorted down to ground. And I was like, that's really weird. Is the cable bad? I tried different cables. When I plugged in the cable, it was shorted when I disconnected the cable, it worked. And I was like, okay, I kind of checked my pit out. And so you know, I looked at my connectors and I was like, well, these look right. You know, there's like the TX. Oh, sorry, let's go to the computer. I jumped to the yeah. Sorry. I got so excited about the story. So I jumped to my computer and I was like, okay, you know, two positives going to the TX, two positive, the negative. I was like, oh, maybe I swapped the negative with positives. And then I was like, well, let me check the pin out in case like I got the clocks or the data is mixed up and there's like some cross signaling. So I went to the dookie page for the connectors that I purchased and I looked and I realized like, oh, I totally like got this kind of messed up and see if you can spot the error. So here pin one is TX, two positive, but pin one should actually be ground. It should be the shield. These two pins are swapped. So it should be ground, positive, negative, ground, positive, negative. But what I did is positive, ground, negative, positive, ground, negative. So I messed up when I did the pin definition and this happens whenever I use a new connector or a new chip. It's so common. I often make a mistake. I try to check, but it's I'm in a rush. I'm tired. You know, I don't quite read the data sheet, right? So what happened is that the positive and ground were swapped. The negative worked and so it's differential and so like, you know, the video capture card that Phil has is really good quality and it was it's meant to deal with like really terrible signal generators. And so it was like, well, you know, you're missing like your positive differential, but the negative is there and compared to ground like the signals, okay. So it, you know, it was able to extract the HDMI signal from it. But yeah, that's definitely going to cause problems. So what I'm going to do is I'm going to fix the definition. I'm going to do another spin of the board, even though I'm like 99% sure that this was going to solve everything. I'm still going to order only a couple of PCBs and verify. So, you know, I learned stuff and then I thought I would quickly show. So that's my, let me close out the DVI bell. I'm going to revise that and oh yeah, and then this was the I was like trying to compute. Well, I, you know, I compared against this, which interestingly enough, I think, I don't think I messed this up. I think the full size HDMI does have a different pin out and that's why I was confused. Although I pulled this up to make a note of myself to verify that it is in this case, it is positive ground negative positive ground negative. But, you know, now that I'm looking, I should actually verify that that's also the correct pin out. But the DVI feather works great, so I don't know, maybe I'll do that in my own time. Okay, how much let's see, how are you doing on time, Mr. Lady Ada? Okay, I thought I'd share some quick some quick prototypes. Hold on, let me put away my DVI stuff. Let's go back to the overhead. All right, so DVI feather got to redesign it. So I got some cool prototypes that I haven't even like plugged in. Who knows if they work. So these are DWM 100, sorry, DW1000 feather wing and feather. So this is the RP 2040 with the DWM module. And these are ultra wideband modules. I've never used them before, but they're kind of the only thing that does what they do, which is indoor locationing. So from what I can tell if you have three or four of these in a room and you put them like in the corners, like like kitty corners of the room, then you can have a node that's floating around in the room and it can like do really good like within a couple centimeters location indoors, which is a common thing that people want to do, especially for art projects or like like scientific projects, they want to track something within a large container or room building but you can't get GPS indoors and Bluetooth isn't really designed for that. Like you can do rough like are you kind of in the approximate area, but Bluetooth isn't really good for that. So ultra wideband apparently this does the job. These modules are not cheap. They're I think like 15 bucks a piece, but again, they're kind of the only thing that does the job. So the DWM 1000, I think there's a new version of 3000, but I'm going to start with the 1000 because it's like I can get these modules and they're the other available and like the 3000 are pin compatible so we can always update from there. Okay, so I think that's oh and then I got one more prototype. This is the feather can. So this is the RP2040 with canvas built in I couldn't get this working. So I gotta figure what did I get wrong? Maybe I swapped some pins around again. We'll find out. Okay, so with that, I think we're ready to go on to the great search. The Great Search brought to you by Digikey and Adafruit every single week. Lady user powers of engineering WSU find things on digikey.com Lady, what are you looking for this week? Okay, so this week I'm we've already done various great searches on FPC connectors and cables but I need a specialty one this week. So let's go to the overhead and I'll show what I'm looking for and why. Okay, so we've got these boards called QT Pies and these are adorable little mic controller boards and we've had like a wide variety of add-ons that we do so hold on one second. So like, you know, we've got like a little keycap add-on. We've got a little add-on that adds like a button in a neopixel or an LED grid. Okay, so what I wanted to do is create an add-on that would let people connect the QT Pie to our TFT displays. So almost all our TFT displays now come with an iSpy connector which is a cute logo that Mr. Lady had come up with and this is a flip top 18 pin 0.5 millimeter pitch FPC cable looks like this, right? And then when you plug it into here, it brings all the IO connections for the TFT like all of these pins down here the SPI, the backlight SD card, whatever all come out this cable and so you don't have to do like this gross wiring where you solder to all these pads. You just have this like slim, cute cable and it goes to whatever your peripheral is and we've got a breakout that you can connect it to so you can have a cable a couple centimeters long this is elsewhere, this is now easier to mount because you don't have all the wires. So I thought it would be cool if there was like something where like, oh, this cable is kind of the same width as the QT Pie, like maybe you could plug in and then like so and then you would have like ESP32 or SAMD21 or RP2040 just driving your little display. You can make great little display projects. Very common. A lot of people like to use these TFT displays. So I did design a board and I used the same connector here. So this connector, again, 18 pin 0.5 millimeter pitch. So I made like a breakout and I was like, well, maybe I'll have it like come out the middle because the issue I had is we could see that connector is like super, super tight fit. Like if you measure this connector, hold on, if I measure this connector sorry, if I measure between these two contacts, it's like 13.2 millimeters which is just like, you know, a hair on it's basically 0.5 inches, right? It should be 0.5 inches. What happened is that this connector is 0.52 or 0.53 and so the connectors are actually bowed out a little bit and then I just bent the pins back in but really this connector should be narrower than 1.5 inch because this you know, this whole thing is 0.7 you know, the hair over 0.7 and then each one of these is exactly 0.1 inch so it needs to be 0.5 inch or less but the connector we've got right now isn't 0.5 inch or less and I actually realized it's there's a lot of connectors are fairly wide but we want to find one that is bottom contact, I do like the flip top because I feel like it makes it really easy for people, like anything with especially if I do something with this style flip top you actually have a shot of opening and closing if it's a pull out, you know, usually the little ears are much wider and they're going to be hard to get in so I want it flip top, bottom contact 18 pin 0.5 millimeter pitch so let's go to the computer and I will take a look, so we were looking at this HDMI connector which we're done with so let's go back to Digikey and I'm going to look for FPC connector, start with that and I want a connector assembly there's like 18,000 so it's a good shot that I have something here, okay a lot of this might be something, you know, just looking at the photos again I like to look at the photos just to be like am I on the right path this one you can see the width, you know, I can't mouse over, but you can see how the contacts are in the center and then there's just a lot of space on the sides for mechanical strength, this one too like you can see the pins, the connector is significantly wider than the pins I want something more like this not like this let me see, I also like that like this one, you see it's not too much wider so let's get the specifications we need out of the way so number one, I want to be an active product in stock I want it to be 18 contacts and the pitch is 0.5 millimeter so that should really pare down a lot of things, yeah we're down to like 100 out of 18,000 I also want it to be in stock right now okay so about 50 out of all of those the FBC thickness I don't really, you know I find that it doesn't really matter, oh I do need to have it be bottom contact, right I want that and then I think I want flip lock but I'll look at the slide locks in case there's something interesting there, materials I do not care too much about so it's about half of them are bottom contact okay so then, you know, looking again this one significantly wider and I'll show you how to read the data sheets, oh this one, sorry this one is not the useful data sheet but like this one, okay so see how there's the pins and then the body is wider but how wide is that body let's find out you go to the data sheet and hopefully this one will be useful it'll have the yeah so what happens is that for FBC connectors you're not going to get all of the measurements in the diagram, instead what you have to do is you look for like these letters, so in this case I want to know the A width, right so this width here A is the total width B is the width between the two pins and then there's like C which is like the, you know, connector width I want A and it's not always the same letter by the way and then you go down here and then you look up how many positions you have and in this case it's 18 and then they say A is 13.3 and I need hold on I want something that's 0.5 inches which is 12.7 so I want like maybe 13 but really less than 12.7 millimeters this is too wide too wide, this also some of them are like okay this also looks too wide this looks too wide maybe maybe you know and so I started kind of looking through these and I was like a lot of these are really wide and then I was like you know first off let me you can't search my width by the way I was like thinking like ooh is there a size now so I thought like well let's do it by price and I can start with pricing because I do want to have an inexpensive connector and some of these were fairly promising some of them didn't have images this is actually a vertical style this is pointing up which I don't want also fairly wide fairly wide kind of wide and then I came down to this Amphenol one is like super wide also wide, wide wide and then I came to this one and I was like ooh that looks nice because you see how there's the contacts and then the mounting tabs slim looking connector so let's take a look so again what I want to look for is the A width because this is the generic you know this is just like N pins so I want A so let's look down at A so I have dimension A and this is like weird because the contact quantities over here contact quantity 18 with 11.5 which is well less than 12.7 so this is my winner and it's Amphenol so they're like you know known to be good and there's actually quite a few others but the pricing is very good you know it's about 40 cents in quantity and you know it's a nice I like that gold plate over here I like that it's flip lock and Amphenol connectors are like pretty good quality connectors I've never had any issues with them so I'm not going to worry about like the little tab breaking off so this is my great search find that's a great search we're going to bounce this week because we got a bunch of stuff to do get set up for the weekend stay hydrated everybody we're hanging out with this tonight some of the shows during the week alright thanks everybody bye everybody