The quest for the right connector for a project! The right of passage for any hardware electrical engineer starts with a connector catalog.
This is the last installment of Stephen's 'Adventures in Injection Molding'. We are going to recap the entire two year sage and close the book on it.
The Jeep Prop Fan project rides again! Well some iteration of it at least. Lets design an open source PCM (Power Control Module) for automotive apps!
Visit our Slack Channel and join the conversation in between episodes and please review us, wherever you listen (PodcastAddict, iTunes). It helps this show stay visible and helps new listeners find us.
Parker is an Electrical Engineer with backgrounds in Embedded System Design and Digital Signal Processing. He got his start in 2005 by hacking Nintendo consoles into portable gaming units. The following year he designed and produced an Atari 2600 video mod to allow the Atari to display a crisp, RF fuzz free picture on newer TVs. Over a thousand Atari video mods where produced by Parker from 2006 to 2011 and the mod is still made by other enthusiasts in the Atari community.
In 2006, Parker enrolled at The University of Texas at Austin as a Petroleum Engineer. After realizing electronics was his passion he switched majors in 2007 to Electrical and Computer Engineering. Following his previous background in making the Atari 2600 video mod, Parker decided to take more board layout classes and circuit design classes. Other areas of study include robotics, microcontroller theory and design, FPGA development with VHDL and Verilog, and image and signal processing with DSPs. In 2010, Parker won a Ti sponsored Launchpad programming and design contest that was held by the IEEE CS chapter at the University. Parker graduated with a BS in Electrical and Computer Engineering in the Spring of 2012.
In the Summer of 2012, Parker was hired on as an Electrical Engineer at Dynamic Perception to design and prototype new electronic products. Here, Parker learned about full product development cycles and honed his board layout skills. Seeing the difficulties in managing operations and FCC/CE compliance testing, Parker thought there had to be a better way for small electronic companies to get their product out in customer's hands.
Parker also runs the blog, longhornengineer.com, where he posts his personal projects, technical guides, and appnotes about board layout design and components.
Stephen Kraig began his electronics career by building musical oriented circuits in 2003. Stephen is an avid guitar player and, in his down time, manufactures audio electronics including guitar amplifiers, pedals, and pro audio gear. Stephen graduated with a BS in Electrical Engineering from Texas A&M University.
Special thanks to whixr over at Tymkrs for the intro and outro!
Welcome to the macro fab engineering podcast where your hosts Parker, Dolman and Steven Craig, this is episode 129. So we're gonna have a shout out to our French listeners since y'all won the Soccer World Cup. I mean football, World Cup.
we have 40 listeners from France. So congratulation. They probably went absolutely insane. And on the flip side, in Croatia, we actually have one listener there. And so if we were, I mean, y'all came in second place, but if y'all want to one, this thank you would be just for one person in the entire world, one out of 7 billion people.
You know, what's funny is like, over here the World Cup is I mean, there's plenty of people who celebrate it, but it's just it's nowhere near the same and and so when it comes down to like, people who are rooting for France or Croatia, it's like, they visited there for one day, one time in their life, and they're like, that's my country, you know, they're going for it.
Four years ago, it was pretty big here in the States. But you know, the United States didn't make the cut this year. So, you know, I didn't watch any of the World Cup because it was just one of those. USA is not in it, so I don't really care. Yeah,
I watched it was fun. I love the World Cup. Yeah, the the Russia Croatia game was awesome.
Oh, yeah. What score? Uh,
what was the score? I mean, it came down to it was it was Tie game and then they went overtime, and then it was still tied. So they had to go to like, the free kick. Oh, it was Piquet's. Yeah, yeah, it was. Yeah. And it was like biting teeth kind of or biting nails kind of stuff. Bite. Gotcha. So that's really weird. Yeah,
it was awesome. Really, really crunchy. Okay, um, so update from last week, I think. Yeah. The connectors for the jeep. PCM arrived. And they fit perfect. Nice. They are identical match. So I'm going to spread those part numbers around on my blog in the jeep forums. And hopefully, that will help people out.
How many beers did it take for you to swap them out?
I haven't swapped them out yet. Oh, I just I just unplugged them and then plug the blank ones in. And they fit
perfect. And it's it's a it's a multi piece connector, right? Like it has to kind of like split apart and then come back together.
Yeah, a little bit, but not too much like the backplate pops off. And then you move a locking mechanism is actually a sliding mech. So you slide that over, and then you put all the pins and slide it back and then you pop the back on. Sounds robust. So are the grommet kind of thing on? Yeah, no. So it's pretty easy. I've taken them apart when I was doing the cruise control stuff, I had to take mine apart without breaking them.
Right. And each one of the wires kind of goes into its own little gland. Right. So it doesn't get grind down in there and stuff.
Correct? Yeah, though. Completely waterproof. Yeah. Cool. I think my my Mac 6682 breakout boards, they'll be here at the end of the week. So that's gonna be cool. I can't wait to actually get those thermistors running. Yeah, start doing some actual testing. Yeah, I have to bust out like my development board, which I don't know where it's at. So I'm probably gonna write the code on my prop, because I'm pretty good at doing I squared C on building a squared C drivers and spin and then porting that it's funny cuz I like prefer writing them in spin and then porting it to see that makes any sense? I don't know. I think it's just the structure of that language is just so much better at like speed. Speed.
coding. Yeah, maybe not. optimizations, feed, but coding. Yeah.
But actually coding and getting it working like hooking it up and actually working on like, okay, that works. Now I'm going to port it to C and make it run on you know, FM eight or ESR, MSP 430 or whatever I'm
using to hell a lot of translation going on there.
I think I'll post the code next week if it's if I had those boards in cool. And then I ordered some of those map shitty add ons. So I ordered one for me
actually well last week we were talking about not having them but now we are going to have them so
well. One yeah one yeah because I ordered it
but we have actually had some other people order them right. Yeah, we had
zap and hire on they ordered I think like three or four of them right? For their badges that the end on XOR the crazy Bender in Westworld badge Bender on a bender. That was last year's Yeah, that was Ben Bender Rodriguez in Fear and Loathing in Las Vegas, but this year's Westworld for them. So they ordered some shitty add ons, map ones for that. and zap and Chiron was on episode 69. Incognito Mode. And they're also on Episode 109, which is Arduino the gateway to hashtag badge life. So go check those out if you want to listen to zap and Chiron. And Steven and I talk a lot more. And then Brandon satrom, who was on episode 122. And we built the particle IoT stuff. And that was the last that was the episode, Steven was moving to Colorado. Right? And so he ordered he ordered one as well. He's big into the hashtag batch life as well.
You know, I need to go back and listen to that episode. I still have yet I poked into just a moment of it. But I actually want to get into the particle a little bit. I'm actually helping a buddy, do some some IoT stuff.
It's a very good article to get started. Not that platform.
Great. Yeah, no, I need to, I need to listen to my own podcast.
Cool. And then the big thing I've been working on is, you know, the wagon, of course, basically been rewiring the engine harness because the previous harness was just kind of sagging on the engine. And it was like getting hot from the exhaust manifold at look like it was on fire at one point of its life. So I wanted to fix that. So I rewired it over the weekend and extended some of the wires out chopped out all the stuff that was bad, put a new wire where it needed it and it looks really good now. And the one thing I wanted to do though, was I was basically like, on bubbling, the wiring harness. Anti Baba, yeah, I was like taking all the hacks out and putting it all back to stock OEM style. But the number one thing was the AC compressor clutch mechanism, which is a magnetic clutch and energize it and engages the clutch. So the air conditioner works. This had been bypassed. And so there was a switch on the dash that you pressed and it turned on the compressor activated the clutch. And so I was like okay, there's a reason why someone went through the trouble of drilling a hole in my nice dash now.
Oh, don't lie, you want to do that? You know, I would have fixed the problem, which is what I did. Yeah, but you you want to drill holes to add your own shitty wagoneer add ons.
Nuts. S who? Yeah,
swells. So I pulled up the factory service manual and started looking at like, why it wasn't working. I think we covered this a couple podcasts ago of like how the AC module worked. So there's like a thermistor. And then there's a potentially ometer adjust how much temperature you want all that good stuff. And so I actually like pulled the module out from underneath the dash unplugged it and then I actually went through the test procedure and made sure, okay, the thermistor is reading like 4.2k ohms. And that's like, around like 7578 degrees somewhere in that range. So I'm like, okay, so that thing's working. And then I'm like, move the potentiometer on the dash for the temperature control, and I'm getting a sweep on my multimeter. So I'm like, okay, that's working. And then I probed the 12 volts and ground housing 12 volts and ground. And then I put the meter on the compressor line and then went out into the hood where the the previous owner disconnected that that that wire and clipped it up. And I had continued it. So I'm like, okay, everything about the wiring was good. There's nothing wrong with the wiring. Just convenient. The all he did was cut at the end, it didn't just like cut the whole thing out. So I did I took the AC control module and opened it up and immediately saw the problem.
Yeah, I'm looking at the picture right now. I see the problem too.
Yeah, it has a one of the transistors had a self destruct sequence. And basically, it looked like it shorted all over the PCB. I've never seen anything remotely like that. Of how energetic it was.
Oh, yeah, no, it barfed all of its guts all over the board. Yeah. And
the thing is, I tried to clean up whatever it is, it will not come off the board. It just stuck on usually that
2020 years old transistor guts,
you know, transistor guts all over that PCB. And so the fortunate thing was when I open up the board, the other half of the transistor Philhealth, which has the part number on it.
He got really lucky on that. I got
I got really lucky. And it was a I had the my notes A to N 4403. I'm like, Ah, I've used those before, and I can buy those locally at ACE electronics, which is our local, like electronics store here in Houston.
Yeah, they're like a few streets over from where macro fab is. Yeah. So
I picked up one of those and I picked Well, I started I started doing more analysis to the board, so I took the transistor off, and then applied power turret and it's still said there was a short and it turned out the there was a diode one and four. Wow, what is it for?
Is it on your little schematic? Yeah,
it was D for my schematic, the one and 4158. So I didn't know that was the exact part number for because it's a glass diode. But I assumed it was that part number because that's like the most popular glass diode there is
minus a 41485858. I would I would think the 4148 is 4158. Okay. Yeah, they're both probably popular. Yeah, very popular. And
it was like it's a diode that's it's being used as a flyback diode on the relay coil.
Oh, it's just protection. Yeah. So you could slept practically any day out there?
Probably. So I've Well, I figure what happened in the circuit was the flyback diode probably failed. And sometime in the last 30 years, right. And then the next time it got actuated, the relay spiked the the to end for 403 and blew it up. Yeah, yeah. Yeah. That's the what makes the most sense, because the that transistor is driving the relay. So it would get the brunt of the transit spike if the relay cut off without that diode?
Yeah, yeah. Yeah, for sure. You know, I think that's actually it's actually worth talking about that for a second for maybe maybe there's somebody out there that doesn't know like, if you're, if you're using a relay, inside the relay is a coil. And the coil is in effect, a giant inductor. So when you, when you turn it on an inductor is going to resist a change in current, it doesn't, it doesn't like to have a lot of current change. So when you when you turn off a relay, the the inductance will actually cause the voltage to spike to, you know, who knows what it just it all depends on a lot of different factors. But it can be a lot of voltage. So we put the we put a diode across the relay coils to provide a safe path for it to discharge and not damage anything else. But if that diode fails, that line could be at, you know, upwards of 1000s of volts.
Yeah. And that's actually a main failure of pinball machines is the diode because they put diodes across the coils in pinball machines that do all the flippers and stuff. Yeah, they put the diodes on the coils because it's the closest path, right? It's like the it's close to the coil as possible.
Oh, you want to get you want to as close as possible to the relay? Yeah.
So what will happen is these these diodes will fail sometimes, and then it will blow up the MOSFET on the control board.
Right, because MOSFET MOSFET. You don't like a couple 1000 volts reversed. Yeah, exactly. They're not fans.
I think this is exact same thing that happened here. I basically I replaced the parts. And then I actually made a little test jig. So I got like a resistor that would be like it was like 4.2k or something like that. I just pulled out the part spin. And then I put up a low potential rheometer on it, the replicate the 10k temperature stuff, temperature setting. And then I powered it up and then my slot slid the potentiometer back and forth. I can make the relay click on and off. I'm like, Okay, it's working now. Yeah, nice. Then I took the design. I'm like, oh, let's make a schematic of it. And so I reverse engineered the schematic, and I mean the layout, and posted it in our Slack channel. And the thing about it is I couldn't really make heads or tails of it. I agree drew it so many times just trying to figure it out. I actually sent it over to Steven and Steven was like, that looks familiar. But I'm missing something. Yeah. And Tom Anderson rewrote the schematic as well. And he basically made it readable, for me, at least, basically the two NPN transistors in the single PNP and a couple of resistors and capacitors in there make up an op amp circuit. And it's been it's basically a comparator for the cut off.
Yep. Yeah. It's, overall it's a comparator that's realized in three discrete transistors. Mm hmm. Basically,
so like the potentiometer that's on the board sets the cut off, and then the, the temperature setting on the potentiometer and then the along with the thermocouple or thermistor, set the other cut off or set the level that varies, right, right. Or just a little interesting, but um, apparently it works.
Which which, you know, it does, it does screen at first, like, why would you do it that way? You know, why would you why would you do a discrete transistor thing when you could just throw an op amp package in there, and you're already doing through holes? So you could just pick any through hole dip, you know, up in package.
And so I asked Tom that I'm like, you know, why? You know, is it just because of cost? Because it's back? This was designed in the 80s. Yeah. And so was it because of cost? Well, op amps, a lot more expensive than because nowadays, an op amp is probably cheaper than three discrete transistors, at least in assembly. But back then, you know, labor was a lot less expensive. And so he said, Yeah, that was probably it was it was the bill of materials were were less expensive, but also, back then in the 80s, your plastics that were encasing your ICS, were not really robust, unless you had ceramic icees. And so you wanted, if you wanted high reliability, you wanted to use discrete transistors instead of ICs. Right, right, which makes a lot of sense.
And it might also be you know, that they're designing this car to be able to go through a huge temperature swings. And so maybe, maybe an op amp circuit, for the cost to get an op amp that would be able to handle the temperature swings might not be, you know, super easy to get or might be expensive.
I would assume this device outlasted its intended lifecycle. I mean, most people do not keep cars 30 years.
That's true. Yeah, for sure.
So it's working. So I basically I fixed the module, and I popped it into on the harness. And then I put my meter back on that cable that's underneath the hood. And I flipped the switch, and it got that cable got 12 volts. And so I removed all the bypass circuitry and hooked that wire back up the compressor. And now the AC module works as came from the factory. So that's pretty cool.
Nice. Yeah. So you're gonna post up the picture of the the deep fried PCB, deep
fried PCB. Yeah, I'll post that in all the the schematics and stuff that we came up with. And I'm actually thinking about routing that board out and making like a replacement board for people. Oh, that's not a bad idea, just so that people can order them. Do it surface mount also. Yeah, I was gonna do all surface mount except for the connector and relay. This This module is in was in a lot of 80s cars, and there's no replacement for them now. So most people were like, Oh, it broke. I'm just gonna go to the junkyard and find one. And I'm like, Well, eventually, that's going to run out.
Yeah, yeah. So there's a little trimmer, trim resistor on the board. I guess that's just for like calibration.
Yeah, that's the you can actually just that so you can set when the compressor kicks on and off. Hmm. Yeah, that's the part of the comparator circuit.
Interesting. Doesn't look like there's any capacitance in the feedback path of the comparator. But I guess I guess with these discrete transistors, it probably doesn't matter too much. Just so that there's no like ringing or anything like that. But also thermistors change so slowly, that I'm not I would doubt that. There would be a huge amount of issue with that. Yeah, long oscillation. Yeah. Cuz that's it. That's another thing that's not really great for a relay is to just hammer its coil with with oscillation. They don't like that very much.
Yeah, I think it's because everything just moves so slowly. Cool.
It's funny. After after Tom kind of wrote that schematic that or redrew your schematic in a way that is a tad bit more readable, or more recognizable, I should say, as soon as I saw that, immediately, a new circuit just popped into my mind, or not a new circuit, one that I've dealt with a handful of times. So there's there's a guitar amplifier that was designed originally in the early to mid 80s. And it's actually different variants of it are still in production today. But it's made by a company Mesa Boogie, and it's their mark series. So they've got mark one all the way through Mark five. And one of the trademarks of this amp is a graphic EQ, where it has sliders to represent the cut and the boost at particular frequencies. It's basically a whole bunch of like peak and knotch filters that you can control. Well, interestingly enough, one of the main driving circuits that is surrounds this EQ is a discrete transistor, op amp. And I've actually put the schematic up here looks super close to Yeah, no, it's it's it's like it's really really, really close. Yeah, it's got a capacitor in the feedback there of the the C 41. Yeah, yeah, yeah. And and that's actually that's for stability. So, so this is being used as like this. This is being used as an actual op amp. So you know, within an op amp, you have a differential pair, which is two transistors on the front that share current in a way. And then you have a gain stage, so that you have the differential pair for the two transistors looking at each other, and then some kind of gain stage right afterwards, which in this case is an NPN. Because this for some reason, I don't know why, but these guitar amps ran on, I'm sorry, I don't know why this circuit ran on negative voltage. And in tube amps, there's a really convenient negative voltage rail. So take every transistor that you have in your circuit and flip it from NPN PNP. And you can still make an op amp out of it. And even to today, they still use this circuit, even though you could very well plop in an op amp and do the exact same thing. Probably do it better.
It wouldn't sound the same. Yeah, yeah. Well,
I mean, but it's funny because this is a this is a an honest to god silicone solution to a problem that is in the signal path of a tube amp. And people don't really seem to care about this. But like, as soon as I saw that, the schematic that that Tom put up, I was like that that's the EQ from Mesa Boogie. So I've actually built this particular EQ a handful of times and some discreet op amps. It's actually a lot of fun to do. Discreet op amps.
You know, what's funny is on that board, there's a lot of no pop areas. And I bet you, the company who designed is implemented a full on op amp with feedback, and then cost reduced
it. Ah, yeah, they got rid of the stability. Cost reduce
that all until Oh, okay. This is the minimal needs to actually run the air conditioner. Well, can we got to save those couple pennies?
Yeah, I probably. Yeah. Wouldn't wouldn't surprise me. So yeah. So if you've ever seen this schematic before? Yeah, actually, I would be interested in seeing if if anyone else has some discrete op amp circuits that are not used for wanqi, ifI audio stuff, like something where it's a discrete up. Yep, that was built for any other purpose. I would love to see that. That would be really cool.
And this is the first time I've ever seen it. Yeah, yeah. Period. So and it's an MVC control module, which is kind of weird.
It is, yeah, it just it this is I think this is a great example of older electronics being built to a price point. And especially because if you look at the board, it's a single sided board. You get no silkscreen, and then like the through hole headers, just pins in holes. No, no, this is clearly built as cheap as possible. So some engineer out there did an analysis and found that three transistors plus a handful of resistors was cheaper than, you know, however, many op amps they would have to buy to fill this crap.
You know, so I don't know, the thing I did on that was I replaced the electrolytic capacitor, but same value.
After this much time, it's not a bad idea.
I'm just like, yeah, it's 30 years old. It's been in like a hot car all of its life. It's just replaced that and I mean, seriously, like it, it works great. I did buy extra diodes, and extra transistors, just in case if I plugged it in and exploded again. Yeah. I think I spent $5 on all the parts. And now I had to deal with a hole in the dash. You know,
actually. interesting topic. Electrolytic, we probably won't go too deep into this. But I was I was actually designing some stuff not that long ago, where I was looking at electronics. And if you kind of look at the lifespan of electronics, like on Mouser, for example, they give you a pulldown list of, you know, here lifespans, and it'll be like, you can pick 1000 hours, 2000 hours, you know, 10,000 hours. And and at first, like, like, oh, yeah, great, this'll last a long time. But when you actually like, you know, calculate that out, say, a 2000 hour things, that's only a little bit more just a tiny bit more than two and a half months of continuous runtime, you know, and know that, that that lifetime thing is based on a whole lot of characteristics. The cap will last longer than than that for sure. But, I mean, if you're, if you're designing a circuit to be in continuous use for a long period of time, then you know, you got to be really careful. You can't just like slap any old Joe Schmo electrolytic in there, because it just won't necessarily last.
Yeah, I think we should cover that in a future podcast. I'm
gonna write that down. Yeah, picking picking the right electrolytic Yeah, for lifespan. Yeah, yeah, that would be fun. Yeah. Also, something really important to pay attention to is where you put the cap on your board. Not necessarily for power supply or anything like that, but you don't want it the next hot stuff or
Yeah, heat you don't want next to your 7805 heatsink regulator
even though electrically you do want it next to it. Yeah, but you don't want it like touching the heatsink? Exactly. So yeah, that's a good topic. We should we should we should get. We should get dirty with that.
Yeah. Cool. You got anything else do
a discreet op amps are cool. They're they're pretty fun. Give it a try. I mean for I mean, Parker you probably won't because it's not your jam but some of our listeners, some of our listeners might give it a try because it's actually first it's easy to get a discreet op amp doing op amp things, but it's really hard to get it doing them. Well. Yeah, it's fun. Makes you makes you appreciate the little black chips
onto the RFO this
right? Yeah, yeah, yeah, let's jump in RFO
CAD five was released this week. I don't really have an opinion on that. I guess. It's just a big news item for this week.
A lot of a lot of our listeners use key CAD. And some some of them are probably yelling at us right now because we're not pronouncing it right.
I actually think it's both. It's gonna be key CAD or chi CAD.
Oh, is it? There needs to be a consensus on that, you know?
Oh, have like a webinar. Yeah.
I don't know. Or just the whoever like is the main contributor to KY CAD or chi CAD just come out and be like, This is it. It's kinda like GIF vs. GIF. I can't even believe that I said GIF. But, you know, it's, it's kind of like that.
Yeah, apparently, it's got new features and blah, blah, blah. It's just like one of those. I don't know. I I like Eagle so it's gonna be I've tried Kiki at one 4.0 came out. I tried it. And I don't know. It just does. Just the interface is so different from anything else. That I'm like, hell no, it just wasn't worth my time to relearn something like I use dip trace I can I can navigate and use dip trace. Well, I keep CAD is just for some reason. Their design decisions on the GUI and everything is just not it's not my style.
Sure, sure. I feel like they have if you take all three of those Eagle dip tracing in KY CAD, I think he had spent a lot more time just trying to make their their buttons look prettier. And like, there's more like just graphics that look nice. Whereas dip trace and Eagle sort of look more. You know, just like to straighten to the point, you know,
yeah. Since like version like Eagle three, they use the same ache icons until like version nine. Yeah.
But but but correct me if I'm wrong, you would know the answer to this. But Eagle guys like the fact that eagle is very Eagle like it looks and responds the same all the time. You know,
they're changing up how the mouse interacts a bit. Autodesk says, I'm not a big fan. Yeah, we'll see what happens because like the right click now cycles, different modes. Didn't it? Always do that? Yeah. But like, differently. It's weird,
huh? Okay. I always liked how when you're routing in Eagle, when you right click, you can choose the different route styles.
Yeah, that's what happens. But like, I don't know, it just feels different. Now. I don't know what it is.
Really? Oh, they started messing with the pride and joy. Yeah,
I think that I think I need to sit down with like version seven, which I still have installed and version i Oh, and look at the differences. And like figure it out. Because like there is something different with the how the mouse interacts with the board. Hmm.
You know, and that's something I'm sure it's really difficult if you are the developer of an EDA tool. You know, this is probably a really universal complaint about people who are not big fans of Eagle, but I just like being able to click on a component and left click on a component and then I select a component like that just that just makes sense to me. And Detroit's runs that way. You can't click anywhere on a component, you have to click on some one of the elements. But it's still like if you click on a pad or if you click on the silkscreen, if you click anywhere you get it. But with Eagle, you have to hunt around with the right click until you find that magic little spot that it selects it. Oh, the origin. Yeah, the origin. And I get that. But one of the hard things I would think of as a developer is making the decision to you know, how do you let the user select a component? Because think of if you had like an eight layer board with a component on top and a component underneath, and you have all the you have a bunch of traces or planes in between there. Like when when a user clicks? What do you give them?
Yeah, so KiCad actually solves that with that context menu that pops up and goes with this left mouse click. You can do these things and it pops up a huge list sometimes and you're like, yeah, and whereas dip tracing Eagle kind of just assume based on what tool you're using what to do.
Yeah, and and dip tray DTrace is not great at that. A lot of times you have to select like way far away from the thing that you want in order to get the thing that you want. Because it dip Trace has like priority levels with selection. And most of the time those priority levels are not what you're exactly wanting. So you either have to like deselect things or turn visibility off for it. So it's not, it's not fantastic. But really key CAD is trying to copy Altium in a lot of ways. There's schematics look like Altium that selection menu thing is very Altium ish. You know, like they they've taken a lot of cues from all because
in Eagle it's you have to use the next function. Yeah, so if you like right if you right click the Select it right click, I can't remember cuz I'm like on autopilot when I'm routing. Sure. Yeah. So I don't know. Like, if someone asked me, How do you run a board and ego and I'm like, watch me do it. Because that's the only way I could show you how to
do it. Yeah, I just put jams on. And then my eyes roll behind my head. And I just go.
Yeah. What I think it's right click when you select stuff. If you if you select if you right click and long things highlighted, you just click next with the left mouse button. Oh, that's cool. And until you get to the right one. I do like KY CAD selection menu, because it's always seems like the last thing you need is like eight clicks through next. Yeah, yeah. It's like, it's always the last thing in the list that you want.
Yeah, actually, you know what? Okay, so recently, I've been using Fusion 360. Because I've been wanting to, we're getting some stuff machined for us. And our machinist has asked for some 3d Step files. So it's like a fusion 360, I can do for free. And so I've been using that. And I'm still kind of new to the game. But one of the things is, you can draw construction lines, which are basically guidelines wherever you wherever you want to draw it. So a lot of times to make things nice, I'll draw construction lines. And then I will dimension everything, such that when I draw my physical lines, everything is all like nice and fusion 360 doesn't cry. But the thing that sucks is if you draw a line directly on top of a construction line, which is most of the time, and then you click, it wants to select the construction line before your actual line. And so it does the same thing where it has like a selection menu. But the way to access it is you have to click and hold it down, hold left click for like a second. And then it allows you to select whichever one, I would think that whatever you're drawing is should take priority over the construction line because the construction lines like a one time deal, but your drawing might be way more than one time.
You know, I wonder if eagle has a keyboard shortcut because it'd be nice if you clicked in it wasn't your right thing. And then you sit like control until you cycle to what you wanted. God, that
would be awesome. Yeah, it'd be really great. Yeah,
that'd be nice. Because then you don't have to move your mouse too much.
Yeah, yeah, that's one thing I really wish DTrace would add. Because a lot of times when you have so many things stacked on top of each other, you have to turn off layers, or turn off, you know, pad selection or turn off. Like you have to go through menus just to be able to select the thing that you want. But then you have to turn them back on to modify the way you want it to be. So it could Yeah, it could be better in that regard. For sure.
And so before we keep going to RFO one project I was talking about I don't know about talking about some podcasts or different podcasts, but the thermal detonator.
Well, that was a tangent.
Well, I know I just I just I meant to add it to the list of stuff I'm working on. But then I forgot and I just looked over my desk and they're like, oh, is this is that from Shapeways? All 3d printed.
Wow. That said, that's nice. Yeah, so
I'll put the I'll start painting it this weekend. I post pictures because y'all everyone that's listening can't see that.
Right, right. Well, and it's the first time I've seen it. Well, professionally printed, I suppose. So thermal detonator is a weapon in Star Wars. For those who don't know, in Return of the Jedi, when Leah visits Java, she threatens him with a thermal detonator. So it is that thing,
that thing. And so I've got a whole box of electronics, I'm going to solder up and put in there like it's like an Arduino, Nano, some LEDs, some switches and a battery. And so that's the first iteration. And I'm actually almost at the point where I'm like, I should just because it's actually really popular print on Thingiverse is design a PCB that just drops in it. And people can just build the PCB instead of having to solder all the stuff together,
right? Because you're wanting it when you flick the little latch on the top. Yeah, it needs
go beep. It needs to Yeah, the LEDs need to light up and stuff and it needs to beep
Yeah, it doesn't have three LEDs that go in a row or something like that.
Yeah, it's got a one LED on top that turns on and then three LEDs in the front. They go beep beep beep
Yeah, I love MC. It's great. Yeah. Yeah. So Parker and I play a Star Wars RPG every Friday night. So yeah, we're dorks
doesn't Dragon, so it's really nerdy. And then at Star Wars Dungeons and Dragons. Oh, yeah,
no, it's like, it's like guaranteed we don't have a life.
I sent you a text earlier where someone modified the new dungeon dragons. Five is the current edition five fee for Star Wars. Oh, and so this is not like because they came up with a new edition of The Star Wars de 20. Well, at Star Wars roleplay is what they call it. Yeah. The version that we play is based on D 20. Back in the 90s. Yeah, yeah. So it's actually a lot of dice rolling and stuff. But they changed it with the recent version. And it's not as good. It's not classic. But this person basically modified the new dungeon dragon rules to be Star Wars and he came out with the new version of that. And the and the Monster Book, which I thought it's actually really well done. I really wish I could give him a shout out by it. I'll do it in podcast notes. Hey, you should check that out GM. Especially the Monster Book.
Is this like for free? Or you can purchase? Yeah,
yeah. Yeah, he has a Google Drive up and you just download the PDF.
I'm gonna Okay, so I saw you sent that and I thought I was gonna look at it after work because I was just like, well, this is probably something that he wants me to buy.
No, no, it's all free.
Oh my gosh. Okay, I'm gonna have to check that out. That's great. Cool.
I want him to come up with weapons books. That's actually the big thing with the version of Star Wars that we're playing is it's really hard to get the weapons book. Stevens got a copy somewhere. I like to get a copy. Yeah, it's hard to get that thing. Yeah. All right back to the art. Earlier this week, a Ben Ben heckendorn was asking me for like, high density connectors. And I'm like, I don't know of any cuz he was like, he was going to repurpose a USB type C connector, because it has 24 pins. And I'm like, gets a really good idea because you can just buy cables and stuff like that. But the bad thing is, sometime down the road, someone's just gonna plug something into that
that's I was I was just about to ESET because like, you could potentially deliver 100 Watts worth of power out that?
Well, that's got to negotiate and stuff. But like, even just like the 15 Watts, it can normally do you sure or like just the five volt line could rock habit. So I started looking at like, high density connectors and stuff. And I found a Molex connector called the molex connector port number is 1719821142 and it's called Nano pitch IO series. That port number is a 42 pin connector. That's like, tiny. Yeah. Oh, yeah, it does half an amp per pin. And the cool thing about this series is you can buy premade connectors from Molex. Like cables. Yeah, yeah. So like you can buy connecting cables already made. So you don't have to go and buy like the, you know, the wire part and then get it made. You just buy a premade connector.
Oh, so yeah, they're trying to support their own board mount connectors by offering cables, cables. Yeah,
that's cool. So I thought it was really cool. The only downside actually, look, when I was looking at the datasheet earlier today for this thing is it only has 50 mating cycles. That's
like, okay, so I could understand if this was, say, on a TV, or something like that. And, you know, it's not intended to be connected and unconnected. But if this was on some other kind of small mobile device or something like that 50 connections in a day. I love this, I'm looking at the datasheet right now. And page four of the datasheet is the the recommended through hole footprint and the next the next one is if they offer both a through hole and a surface mount. And, and these kind of footprints are those ones where like, as soon as you look at it, you're just like,
ah, because you know, it's gonna take you like, you know, hour they take you
to your office. There's just so many, like, it's just starting, it would is like you'd sit sit for a few minutes to be like, where am I gonna origin? Yeah, where am I going to put the 00? And if you have a requirement where you have to put the 00 somewhere out in space, or somewhere like elsewhere. Oh my god, this would take so long.
Well, yeah, it's 42 pins plus all the like mounting connections for
well, it's 42 pins. The Yeah, the mountain connections are non circular. So you have to draw, you know, weird oval shaped things. And then it also looks like it has to like position studs in there too. So yeah, this this would be fun. Hmm. But I mean it looks it looks like it's oh, you know what's actually kind of nice about it? If you see there's a dotted outline around the thing that actually represents where it sits of a connector. Yeah, because a lot of times you won't get this, you'll just get the holes in the pads.
Yeah. And then you have to look at the physical drawing and kind of guests.
Yeah, just like a back and forth thing, which would be horrible for this. In fact, I've actually run into data sheets, where it was physically impossible to tell where the outline was based off of the footprint. They didn't dimension it well enough.
I've run into that with SD card connectors. Yep. All the time until I land on the one that I use all the time. Now. I use it all the time, because I designed it once.
Yeah, and it works. It just works. Yeah. Yeah. Go back and listen to the embedded FM podcast if you want to hear about like, this exact same thing that we're talking about here.
footprint? Hell. Yeah. That's right. Very cool. Yeah, I would say the funny thing is, I would say, electrical engineers are weird in leasing the board layout. Let's go engineers like us that we do a lot of mechanical stuff.
Oh, yeah. A whole bunch.
So yeah, that's a cool connector. If our listeners if anyone knows of any other like, really high density, connectors, like like that, or something that's got kind of like a USB type C, where it kind of like snaps in? Let us know in the comments below or in Slack. And speaking of slack, or loss of RFO is kind of a question from the CMS. So how you pronounce
it, give me a what is it? What can I not see right now? Give me like, oh, a Decimus
Decimus. He's a new person to our Slack channel came into this election earlier this week. He's learning to be a maker. So that's kind of cool. And he asked,
he also he also ripped through our podcast like the backlog.
He listened eight hours a day to Steven and Steven. And I.
Yeah, he. That's impressive. That's crazy. His cheers to you. Decimus. Cheers for all of your perseverance.
I couldn't stand listen to myself for eight hours. So Oh, my
gosh, yeah. But he asked us a question today, we were probing around in Slack been like, Hey, if you want to ask any questions, go ahead and ask a question. So here's what what he came up with. So he asked us kind of gets a little bit of a design question. It goes like this. How would you make a device that could shoot flies out of the air? When I hear a fly buzzing around? I find it highly annoying. And they keep getting stuck in one room at work. Then they spend all day flying up and down the route. So how would you make a device that shoot flies out of the
air? So this thing is you got to shoot the flies out of the air? Right? Yeah, yeah. And they make a buzzing noise. Yeah. So I'm thinking, you build a PCB with three microphones on it? Yep. Okay, yeah. And then, and then a servo gimbal setup. And so he could triangulate where the fly is at. Okay. Use a projectile to shoot at it right. I don't know. I guess making like a mini Railgun or something. I actually don't know what kind of projectile use but that's a different thing. I'm, I'm thinking about like tracking it. Because basically, you would keep tracking it until you heard it. You hear it stop buzzing. Oh, then you knew it stopped moving.
And then you fire and then you shoot a flaming cannon ball at it. Yeah, we're
whatever rail gun or
Actually, it'd be a you know, if you're in an office, it'd be really cool if there was a rail gun that you could load like paper clips into. And it just had like, a vertical magazine of paper clips.
Instead of a Nerf gun.
Yeah, yeah. Yeah. Well, I mean, it just shoots it flies. So okay. You know, a little bit earlier, I did a tad bit of research on this on on flies, actually. So most flies fit within the 200 to 1000 Hertz range. That's their wing flap speed. So you're pretty much guaranteed there. So I had sort of the same idea that you did with having a microphone track. So if you have enough microphones, and a fast enough processor, then you could potentially triangulate where the fly
is. You're not to have a really sensitive microphone set up.
Oh, yeah. Oh, yeah. Especially to like drown out office sounds, or just the air conditioner and stuff. Maybe maybe you could have like, if you could have pre sampled like telephone sounds. So if it ever detected that it would just squelch that sound or what
you're right though, is there's only a certain frequency you would not you would bandpass just that frequency.
Right, right, especially if you knew like there was one species of fly, that's always say 400 hertz or whatnot, then you could really bandpass it and just pick up the fly. Yeah. So I, here's the thought that I had. So you know, when you're at a concert, if you look at either side of the stage, there's those two big, huge stacks of speakers that are curved.
Oh, yeah, the 300 foot tall speaker towers.
Yeah, those are giant arrays. Yeah, what's the line arrays, it's just a stack of tons of different speakers. Now, here's the thing, the guy controlling the soundboard, he has the capability of adjusting the phase of each set of line arrays. And what he can do is he can steer the sound around the crowd. So he can make like cons. You know, he can make like notches, anywhere in the crowd.
I really like where this is going.
So basically, you make a turret that like a rotating turret that has two shaped directional speakers on it flat, directional speakers, and those can line array by adjusting the phase. And you can send out audio pulses that are strong enough at the same frequency that the that the fly is flapping its wings, and you can disrupt its flight. And so it's kind of like a humane way that you can drop it out of the air.
Now, that would be cool. Would that kill it though? No, that's a humane way of doing it. Maybe you could guide it and like force it against oh, what you do is you guide it and force it against the wall, and then you shoot it
or use guy. I like how she the humane way is the guy that to shoot it,
he puts it? Well, the humane way, the humane way at first was actually to tire the fly out so that it just doesn't fly around. And this thing just keeps it if you could steer it, just steer it like out the window. I guess you could do that. But that's but I like that. I like the idea of like this, of having a railgun attachment to the line array speaker device. And then it would you know it would it would push it until the fly was like on a you know a surface and then shoot it
up maybe if you actually had power enough speakers, you could just like base the flight.
Just the fly in there and it just explodes. It's like a puff of blood. That would be great for mosquitoes.
I actually I bet you if you shot a if you took a microwave, yeah. And then directional like and basically made a tube that you could so you can shoot the microwaves in, like a one inch disc. Like a like a waveguide. I guess they actually have laser that that works in the microwave range. I bet you it wouldn't take much to kill a fly,
huh? Yeah, but I mean, well, here's the thing with it with the with the speaker arrangement. If a human walked by, all they would hear is they'd hear the fly buzzing, but they'd also hear the speaker buzzing at the same things. It would just sound like another fly on the desk with a microwave thing if someone walked by, they'd get a little get a little cooked on. Line they wouldn't mind.
Not morons, do you have a there's a new device out there that does infrared charging. Okay, on your cell phone. So you know, like wireless charging is like the big thing where you set your phone down on the pad and the pad charges it up? Yeah. So this is like a device that goes on your ceiling. And it detects I don't know how it texts like where your cell phones that and it beams infrared into a little sensor, unlike your case that you install on your your phone, and it hits the sensor. So you can like laser beam basically infrared spectrum power into your phone. And actually I think Dave Jones did a did a video on it. I don't know, I just saw James Jones talking about it on Twitter. And that's us reminded me of that I'll post the link to that and I maybe he's done a video on it or not.
Well, not really well, if it's dangerous than it could work if it's not dangerous, and it's not powerful enough to charge your phone.
Nothing's good enough. Unless it's danger.
Just so low energy, then like it can't do anything.
But that's like that's like the that's like the Nikola Tesla like car that he could like power over the air. You know that? I don't know the exact story but it's like, Oh, his wireless power thing, his wireless power thing but it was you know, it's enough to cook a human body if
you're close, you know, so it's like, okay, that's not going to work. You like look at your skin just rippling with bubbles underneath it,
but my car is wireless. Oh,
is that is that? Is that in the movie The Mummy.
It's been a very long time since I've seen what's with the scarabs and they Yeah, they go up to your brain and Then they eat your brain. Yeah, yeah, I
think there's I think it's the mummy. Yeah, yeah. With the.
But what is it, Brian that? I don't remember the actor.
I can remember seeing some movies like that I cannot remember actors. So yeah. Okay, yeah, one of my one of my responses is like, well, if you threw a room sized object at the room, you can't miss the fly.
That is true. Yeah. Well, and one of the things about his question is he doesn't actually stipulate no harm to anything other than the fly. He just says, How do you get rid of the fly? So I mean, there's all kinds of destructive methods that you could, you know, have the room implode or something? No, you have
to shoot something at it. Okay. So yeah, so I project to hit the fly. So in your case, it's sound waves hitting the fly. Right? I like that. Yeah,
we did. One of the suggestions was a catapult with paper balls. I think. It just seems really difficult to actually hit it.
I think. I think I think the proper internet turn though is tribute. Shay's. Or do you not know that meme
yet? Yeah, I think I do. Have you ever built a drip machine? Yes, actually. You know,
built to that Scout camp. We built a trophy Shea.
Yeah, yes. So So did I. Yeah. You know, it was funny because we built we had all of our troop or patrols in the troop bill. Each one built a tribute Shay. And we launched water balloons at each other. And it just so happened that the next campsite over was a bunch of professors from Texas a&m, that were engineering professors. And they like they just watched us the whole time. They're like, what? Like, they didn't know Boy Scouts did stuff like this. It's fun. Yeah, we had to make Trevi shades out of sticks. And we got sticks, rope and one bucket. And you had to make a trebuchet.
Yeah, we had a, we had a bucket sticks. We actually didn't build it for anything besides just building it, though. We were we just launched rocks out into the lake. Nice. And you realize like, the big thing with treble Shay's is the sling mechanism. Oh, gosh, yeah, that's 100%. All the engineering goes into the sling mechanism. Because like, yeah, it's a lever with a big weight. And so the last thing is the sling mech that is super complicated to get right. Like, when does it release? How long should it be? You know, how much what's
the angle, the angle that the little finger sticks off? It's all of that matters. Yeah. And you can't defeat it by just like adding more weight. No, that doesn't do make it any better. Like that might work for a catapult or something. But I dragged you Shay's. Well, wait,
it's tension. You're right. You're right. Yeah, yeah.
But like a catapult. You can just add more tension, I guess. And you get different results. But adding more rocks on a trebuchet might just make the whole thing just blow up. Blow up.
So that was the macro engineering podcast.
We're your hosts Parker Dolman and Steven Craig. Later, take it easy
Thank you, yes, you our listener for downloading our show. If you have a cool idea, project or topic or your attribute Shea expert, and you want Steven and I to talk more about that. Tweet us at macro fab or email us at podcast at Mac fab.com. Also check out our Slack channel. I'm sure we're gonna be talking about tribute shows all weekend long. If you're not subscribed to that podcast yet, click that subscribe button. That way you get the latest episode right when it releases and please review us wherever you listen, as it helps the show stay visible and helps new listeners find us
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