- Dustin Holliday is our guest this week. He was on EP#13 of MEP. Dustin has been working on MacroFab’s KiCad parser and is currently researching the KiCad Python API Documentation.
- Stephen and Dustin have also been working on a customer test fixture. The fixture can program an entire panel of boards with an ST Link. A brushless motor is attached to the fixture with an encoder to automatically test the boards. See Figure 1.
- Parker has been working on the Jig Of Destiny REV 3. Parts where ordered on Monday.
- The SSPS front test panel is complete with minimal hardware mods needed. Parker didn’t get to writing test code for it before the podcast but should have something to show on his twitter by Friday. See Figure 2.
- Parker got a I2C LCD display working. Ran into an issue but it turned out his SDA and SCL lines for the I2C protocol where backwards. He is using a Saleae DLA to debug the information. See his twitter post about it.
- Stephen has the analog test board for the SSPS ordered. Has a Pos/Neg rails of 35V, two OPA541 output opamps in parallel, and 0.08 Farads of capacitance. Beefy! See Figure 3.
- The MacroAmp’s PCB has been completed. Stephen ordered the PCB earlier this week. It is a 2 X 10W tube Hi-Fi stereo using Korg Nutubes as the preamp.
- The FCC is going to investigate why the RF noise floor in the US has risen in the past years. Parker thinks its the “cost reduction” of devices after being certified. Will this be good or bad for makers? Does import customers have to test devices now? On the plus side, energy harvesting the RF band is more viable!
- Parker, Stephen, and Dustin get in a rant about Vss/Vdd/Vcc notation for schematics and circuits and Parker offers a solution.
- The AeroScope is a wireless, ultra-portable oscilloscope that uses Bluetooth 4.1 LE to communicate to a phone or tablet for the screen. Would be useful for Maker style field work. 100Mhz, 500M/samples, +-40V input. Fairly typical specifications. Runs $260 on the crowd funding website.
Special thanks to whixr over at Tymkrs for the intro and outro theme!
About The Hosts
Parker Dillmann is MacroFab's Co-Founder, and Lead ECE with backgrounds in Embedded System Design, and Digital Signal Processing. He got his start in 2005 by hacking Nintendo consoles into portable gaming units. He also runs the blog, longhornengineer.com, where he posts his personal projects, technical guides, and appnotes about board layout design and components. Parker graduated with a BS in Electrical and Computer Engineering from the University of Texas.
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.
Host 1 00:10
Hello and welcome to the macro fab engineering podcast. I am your guest Dustin Holliday.
Host 3 00:15
And we're your host, Stephen
Host 1 00:16
Craig and Parker Dolman. So Dustin has been doing more engineering work here at Makram. But yeah, I think the big thing is he brings a lot of programming experience to to the team. And so you've been working on cute cat right?
Host 1 00:34
Yes, I'm I'm a big fuzziness.
Host 1 00:39
Yeah, that's not us.
Host 3 00:41
We got the maker Trifecta here. Yeah, it'll dip tracing key kid.
Host 1 00:44
Yeah. All the all the free ones. Yeah.
Host 1 00:48
The ones that have free versions that don't expire. Yeah. Altium has a free version that expires in a month. And their free version
Host 3 00:57
Is you get everything for 30 days.
Host 1 01:00
No, not limited to 10 by 10 centimeter,
Host 3 01:04
Or like 30 parts on your board?
Host 1 01:07
Well, keekaboo is 100%. Free. Yeah, open source. So yeah, what what have you been doing with KiCad? So I've
Host 1 01:14
Been working on a parser where you can just upload your your keycap PCB file, and we'll parse it and generate all the files for you. Automatically. Nifty. That's something that we've been liking.
Host 1 01:25
Yeah. Because we do that for I say, We macro fab. We do that for eagle and dip trace right now. And we almost do it for KY CAD, we parse the XY RS file, but not the Gerber's. Yeah.
Host 1 01:39
And we and we do it the old way before they had the Python API. Yeah. So we're manually going through and calculating centroids. And all that. Yeah. Hardware.
Host 1 01:49
Well, hopefully, you get some results out of that. How about Oh, yeah. How is that API? Because the last time I looked at it, it was before they released? Key cat 4.0. Yeah. And there was zero documentation on the Python API stuff.
Host 1 02:05
Yeah, I think I think I found the old, the old API documentation, there's pretty much nothing on it. It's just got like one little example. That's not even useful at all. And that's that's it. But but they have it well documented. Now they have all the classes and all all the all the methods laid out and everything. So it's pretty nice. One thing, one complaint I have is that you can't actually, it's not like a regular Python package. It's all bundled into KY CAD. So you can't it's difficult to install it into a standalone version of Python. So we're going to figure that out
Host 1 02:38
Yet. Why have to just have a version? That cat on the server? Yeah, but we could do that. Because that's, that's what we do for Eagle. Yeah. Because we have an eagle install that runs the script and runs the conf file generation.
Host 1 02:52
Yeah. So yeah, the key comes with a Python exe. And in the kikar. folder. Oh, interesting.
Host 1 02:57
Yeah. So they probably, yeah, they probably compiled their own version of Python. I
Host 1 03:02
Think so because it doesn't work with with Python versions I downloaded from the Python website.
Host 1 03:08
Ah, that's kind of weird. Yeah. I wonder if it's hooked in or something?
Host 1 03:12
Yeah. So, um, but otherwise, otherwise, it works great. And it's an awesome API. It's really powerful.
Host 1 03:18
And then speaking of Python, you and Dustin, Dustin and Steven have been working on or finished up that customer jig? Yeah.
Host 3 03:29
Yeah, so we have a customer that has a motor controller PCB. Basically, it's a brushless DC motor controller, that, you know, I think you can control up to about two, maybe two and a half 1000 watts. And he wanted us to have a jig that that automatically programs and tests every board. So Dustin, nice set forth and making this, this jig that can actually accept a panel of 10 different boards. And it goes through and actually programs each board and test them serially, all in about four to four and a half minutes. So each board, we talked to each board, we program it using an st link. And then we set each board into a test mode, and it'll actually spin up a motor that's on the jig. And on this motor, we have an encoder wheel that goes, spins through an optical sensor. And we actually read feedback on that. So we can we can program each board test them read back information that the motor is actually spinning and report that to Dustin's Python script that he wrote and get a log of pass and fails on that.
Host 1 04:39
So on that motor coder. Yeah. On that motor coder, could you can you actually read the speed of the motor too?
Host 3 04:48
You can. Right now, we're just doing global did the motor spin. So I'm just counting pulses and seeing that go over a certain number of pulses and that's a pass but when Can we can go and actually get RPM from that?
Host 1 05:02
Yeah, it's pretty much pass or fail though it either it either spins or it doesn't.
Host 3 05:06
Yeah. And the the jig was mainly designed for speed, not speed of the motor speed of testing and product testing.
Host 1 05:13
Yeah. Because there's what 12 boards or 10 boards, 10 boards on a panel. It's two rows of five. So you're down about 30 to 35 seconds per board. Yep. That's not bad. Clean programming. Yeah,
Host 3 05:25
Yeah. No, it's it's really quick. And this was actually the first time I got to do a project with Dustin, which was a ton of fun. Especially because I don't really know a whole lot about Python. So it was fun to get in on that.
Host 1 05:38
So we really interesting as for the next project, y'all do y'all should change places. Oh, that would
Host 3 05:43
Be a train wreck. From my side from my side.
Host 1 05:48
Me too. That'd be fun, though. Yeah.
Host 3 05:52
So yeah, Dustin's pretty good at and hammering out the Python. He did it fairly quickly. A lot faster than I designed my board, that's for sure. Yeah.
Host 1 06:06
I'm the Jigga. Destiny. Rev three, got an ordered on Monday. Should be here sometime like next week. Hopefully we can actually it'll fit into the reflow oven. In the sun.
Host 3 06:19
By the way, I told everyone the other day that you didn't design the jig rev to wrong. It's just the oven was designed wrong. Yeah, that's
Host 1 06:27
Correct. Yeah. Yeah. The oven the oven respect to open up 18 inches. It does not
Host 3 06:33
Your jig wasn't too big. The ovens too small.
Host 1 06:35
The jams at like, a little over seven and a half.
Host 3 06:40
Also, it jams going small, too. They it has a minimum that it certainly does not reach. Yeah.
Host 1 06:47
I wonder if it's just something.
Host 1 06:50
I mean, maybe just need to lubricate the thread. Yeah, maybe? No, let's
Host 3 06:55
Just completely redesign.
Host 1 06:59
Host 1 07:00
We're gonna do it anyway.
Host 1 07:02
Yeah, I think that's the next machine we're getting. Yeah. Yeah, getting at zone. Four zone. I can't wait. To see SpaceX go. The parts were supposed to be here this week. They're not there somewhere.
Host 3 07:18
Well, they were scheduled to arrive at the earliest today or yesterday.
Host 1 07:23
So have you checked the tracking? Are they still somewhere halfway over the Atlantic?
Host 3 07:27
Well, okay, so it was shipped from Australia. And Australia Post has weird tracking numbers, which I can't find. So I'm not sure where it is at the moment.
Host 1 07:36
Oh, so it would be over the Pacific somewhere. Or in California.
Host 3 07:40
I the way that shipping goes it could be anywhere on Earth right now.
Host 1 07:44
Actually, speaking shipping. You know, those? Uh, was it the chip? That was like the $9 $90 computer that you can buy? Yeah, Kickstarter. Mine got shipped. My gets shipped from China to New York. Yeah. I don't know why I went to New York, maybe New York's international hub for
Host 1 08:06
How did it even get there? Like go all the way around Africa to get well? Nevermind sorry.
Host 3 08:16
Hey, Dustin, you know, we fly now.
Host 1 08:18
Oh, man. That's cool. I didn't even know that.
Host 1 08:21
I flew over the Arctic. No, like dogsleds boxes of these chips. And their
Host 3 08:27
Parker needs his computer. It's only $9. Much.
Host 1 08:35
It's like the dinner on race. The way I did wrong, was that
Host 1 08:41
That's that's the big dog sled race.
Host 1 08:43
But in Alaska,
Host 3 08:44
I live in Houston, Texas. I don't even know what snow is.
Host 1 08:49
Like dogs. That's how I know.
Host 1 08:53
I'm SSPs front panel. I did not get the finished coding it this week. I was coding something else. I was coding in a a little i square C display today instead of actually working on the SSPs Oh,
Host 3 09:08
How'd that go? It went pretty well.
Host 1 09:10
The only problem I had is I'm Miss marked the the data and clock lines for the I squared C on more my boards sta sto Yeah, I hadn't reversed. Oh, and so I was just getting a bunch of knacks back actually use our our DLA our saili dla Yeah. And I hooked it all up and then it just goes knack knack knack knack.
Host 3 09:35
Something's wrong. Yeah,
Host 1 09:36
I was like, Okay, actually tried, you know, different things and I was getting, you know, the clocks out and read new thing and I also had it backwards and the sales because Sealy was decoding correctly, but it wasn't getting acknowledged back because the screens, lines were backwards to two levels of flipping at two levels of flipping there. So I was able to just easily just flip the jumper wires. And it worked.
Host 1 10:02
So your clock was going crazy. And then the output was like 1010.
Host 1 10:09
Yeah, it didn't really work too well, but it works now. Dead because you were actually refreshing the screen. Yeah, I was refreshing screen writing data to it. Now I gotta write the entire library to support it. It's been. So you also all you have to do is like LCD dot, you know, decimal number this, and they'll actually write it out. I'm gonna make it like a character display.
Host 3 10:32
Okay, yeah. Cuz I was about to say you wouldn't you have to have the location of where you want it.
Host 1 10:37
You can, you'll be able to move the location around. Yeah, so it's going to have a virtual, because the, the screen doesn't have a counter so to speak, you tell it what address you're going to write to. So it handles all the moving it so the library is going to handle have a virtual pointer, or virtual counter that that will automatically move everything around.
Host 3 11:00
Gotcha. Yeah. Soft cursor. Yeah. Soft
Host 1 11:02
Cursors. See anything else? I think that's it for me that done this week.
Host 3 11:09
Well, I got on the SSPs analog board. Got that up in ordered last week. So we've, we've been talking about the SSPs for a good long while now. And it's it's taken me a bit of time to get the analog board up and running. But I finally hammered it all out. It took a lot of simulation just because I was kind of anal about making sure it was right, just because my board is handling like close to 400 Watts, I want to make sure it's absolutely right. But we have on this board we're doing a single channel and we're going to test and modify this board as much as necessary and then just copy and paste effectively to make the to the to channel. So fingers crossed. This is the one that that should do everything that is needed. It has to 35 volt 10 amp regulators on it. All discreet, it has to Opa 541 op amps in parallel as the outputs and then a whole bunch of digital jazz for Parker to talk to and have fun with.
Host 1 12:15
Yeah, the it's got like what point oh, eight fair adds a capacitance. Yeah. I'll tell you. You told me the spec was in ferrets not in like microfarads. Oh, yeah.
Host 3 12:29
And the reason why I did that is because when you buy these specific caps from Mouser, they are point oh, one ferret. That's the way they call.
Host 1 12:38
So these are actually Milla ferrets, this would be eight Nilufer adds
Host 3 12:41
Eight mil of ferrets. That's right, we have 4.01 caps in parallel per 35 volt regulator. So a total of point O eight fer adds.
Host 1 12:55
Yeah. And then there are two micro amp right. Macro amp I'm sorry. Oh, yeah, yeah,
Host 3 13:01
Yeah, yeah, the So earlier this week, I finally got around to laying out the macro campaign, it's been kind of fun, my customer requirements have dropped a little bit. So I snuck in to PC board layouts. And I'm actually working on a third right now, while the customer stuff is down, but on the new tube amp, I finally got that all ironed out how I want to and got that on order earlier this week. So that's a two channel 10 Watt tube amp using the cord new tubes that we've been talking about for a while. And my goal was to put it on a small PCB, only two layers and have everything 100% of the entire amp on one board. And I got away with
Host 1 13:41
It. It's also pretty much all the signals are on one side and then ground on the other side.
Host 3 13:46
Yeah, yeah. So I I've actually never done this before. And so I'm giving it a try. I did a solid ground plane as my ground. Typically in audio circuits. I run every single ground by itself, but I wanted to try a full ground plane and I had a whole bunch of extra area on the top layer. So I duplicated a ground plane and I vias stitched the snot out of the board. i The my EDA tool head that there was 820 holes in the board. And this is a four and three quarter by four and three quarter board. So it's got holes everywhere. 565 of those vias don't have signals going through them. They're just via stitching. So hopefully it acts as a giant shield. That's should well and one of the reasons why I did it is because it's going in a wooden case. So the entire enclosure for this box is not shielded itself. So I want the PCB to be just a giant, you know, ground sink
Host 1 14:45
Basically, it's speaking around like I just I ran a new version of the dirty pee stompbox. Yep. So hopefully we'll have that done about two weeks and we'll have a I probably have a seat even hear play played on on the podcast?
Host 3 15:02
Oh yeah. Yeah, get nasty.
Host 1 15:04
That's pretty grungy
Host 1 15:06
Guy. I got to play around with an early version. It was a pretty nice pedal.
Host 3 15:10
It's just the the nastiest,
Host 1 15:13
All the thing about it. It's all s&t. Yeah. Yeah. Which is unheard of for stompboxes. But it runs a solid state basically to two and three, nine fours. Three of them in series. Yeah. The cascaded? Yeah, just gain, gain, gain,
Host 3 15:32
Net. Gain with with no attenuation, no. Not really much control, just enough to make sure that it doesn't just like explode. Yeah. The thing about
Host 1 15:44
It's based off the old schematic for a super fuzz. Yeah, Marshall. Super cool. Yeah. And they use germanium cap transistors, transistors, which had their their bases were kind of leaky. Yeah, compared to these new silicon ones. Yep. And so we actually had to bias the first first transistor, just to get the transistor transistor turned on?
Host 3 16:12
Well, because the old way that transistors, there was a a form. And this was a handover from tube technology. If you put a really large value resistor on the base, just the leakage current enough would raise the voltage on the base to turn it on to turn it on. But new transistors don't really. You're not lucky enough. Yeah.
Host 1 16:33
So I actually tried that. Because I basically looked at the schematic and I'm like, okay, that makes sense. You know, it should work. And it didn't turn on at all. We actually debugged it with a, you know, an old 100 megahertz analog scope, just poking on it and figuring out where the signal was stopping. Yeah. And it was the first transistor. And all we did was do like a 10k. Pull up on it or something.
Host 3 16:56
I think we did a voltage divider, just to make sure that we had somewhere in the center.
Host 1 17:01
Yeah, I think we basically we soldered a we did bugged potentially ometer on it, and tweaked it to it sounded where we wanted it. Yeah. And then we just measured it and put two caps. There are two resistors there.
Host 3 17:13
How many? How many times have you have you done stuff like that? For me? It's countless Oh, yeah, do stuff like that? Yeah, that bug a pot. Turn it till you like it, measure the value put those resistors in? I've done
Host 1 17:27
Well, stuff like that. We couldn't really figure out where there's no math formula to figure that out for this transistor. Yeah.
Host 3 17:34
Yeah, yeah, they just relied on it. And which and which is a terrible way because you put in another transistor, it might work. And as if you have an old germanium transistor like that, as it grows older, it may get more leaky or less leaky and just not work. It's a terrible design habit. But it requires one less resistor so it's cheaper so it's
Host 1 17:55
Cheaper. Ah, speaking of cheaper this goes into our first section. The FCC is to investigate why in America, the RF noise floor is been going higher and higher. These past couple of years mysteriously mysteriously, ooh, it's probably because of cheap products from China come in over this is my theory.
Host 3 18:22
Blame it on China. Well,
Host 1 18:24
Have you ever taken apart a power supply and found like parts missing? Yes. They a lot of these devices they'll say like the FCC stamps. They probably were in the original specification. Yeah. And then they don't manufacture to that and then they start removing parts until it stops working and then put that part they took out that made it stop working back in right and so like not ESD TBS diodes we don't need those to make this power supply work.
Host 3 18:55
Yeah. Bypass cats to make sure that things don't radiate. We don't need no don't need those. Here's our processor can handle a full volt worth of ripple.
Host 1 19:05
Well, the USB spec is plus minus point five volt with no ripple spec as a full full volt ripple. Dirty terrible I know for a fact my 3d printer that bought from China, it's a maker bought rip off. Is not FCC or CE compliant. How do you know that? You turn it on and the speakers go hey you're the steppers over the speakers are like halfway across the room. Yeah.
Host 3 19:34
Oh my gosh.
Host 1 19:36
It also makes my Wi Fi go crazy.
Host 1 19:40
You like lose internet or something?
Host 3 19:41
Yeah, well, it's dumping all over the band.
Host 1 19:43
You can watch your your Wi Fi bars dropped by half. How much noise it's pumping out.
Host 3 19:51
That's terrible. I bet you my CNC dumps tonic or that big
Host 1 19:55
Motor? Yeah, yeah. But I guess that motors Probably designed to do that. It's probably a certain frequency band for it. Maybe.
Host 3 20:06
But yeah, so So the noise floor, they've they've identified that it's it's creeping up.
Host 1 20:11
Yeah. So then yeah, in major C cities, it's certainly go up. Yeah. Which it shouldn't. If all devices are come FCC compliant.
Host 3 20:19
It should be they there should be some nominal. Correct. Yeah. So do they have any kind of actions they're gonna take?
Host 1 20:25
Um, the Hackaday article didn't really say what they're going to do yet. That's actually one of my questions is, is what are they going to be able to do about this? I guess they can start. Like, how do you it's most likely cheap products that are not fully compliant.
Host 3 20:45
What if it was iPhones just dumping crap out and
Host 1 20:50
Recall all the iPhones though, I think I think Apple stock or just immediately plummet.
Host 3 20:56
Oh, yeah, they would tank. No, like I would actually know they could make it public just by the FCC. I just raised the limit.
Host 1 21:04
I i FFC Well, I FCC I
Host 3 21:08
FCC? Yeah, there we go. Ah.
Host 1 21:11
But you know, it's another thing is most makers don't even do FCC or CEE testing either. Right?
Host 3 21:21
Probably a lot of them know what
Host 1 21:22
To do. Yeah, yeah. No, no, I don't. So at the FCC starts cracking down on this stuff is really going to hurt like websites like tindy and the Hackaday store. And, you know, these guys that are selling their products that are not actually tested? Hmm. Or they will actually start cracking down on, you know, actually testing devices. Basically, like, you know, random sampling, testing,
Host 1 21:52
That kind of stuff. Seems like that'd be very difficult to do.
Host 1 21:56
There's a lot of electronic devices test. It's like in how do you even stop a product that's coming from overseas here? Does customs have to now power stuff up and test know if they're passing a bill even if because this goes back to you know, even if it has an FCC or CEE stamp on it? It might have been caught, quote, cost reduced. In China, and now it doesn't pass. So how
Host 3 22:23
Does customs know? It seems almost impossible? Yeah, yeah. It's a really do.
Host 1 22:27
It's almost like maybe everyone needs her own. Like, maybe if the FCC came out with like, a little like radio tag that can carry with you. And it would ping if it goes over a certain amount. And then you can like, oh, yeah, that device is bad. And then like market?
Host 3 22:45
Yeah. But I mean, most people would ping and they just be like, Okay, well, yeah, yeah.
Host 1 22:53
That's true. Oh, there's one more supply is $5. Cheaper? I don't really care. But if
Host 3 22:57
It but if it was, like your problem, where it cuts off their Wi Fi signal that that device would be in the trash really fast. Yeah.
Host 1 23:05
That just raising the noise floor slightly?
Host 3 23:07
Yeah. Yeah. It almost seems like I wonder if they can build some kind of like, car that they can drive around and with an antenna and since?
Host 1 23:16
Well, that's what they do for people broadcasting pirate radio. Oh, yeah. Yeah.
Host 3 23:20
Well, they triangulate it. Yeah. Yeah.
Host 1 23:23
So they already do that for for that. And that's also how they get people who do ham with the high powered radios and stuff that they shouldn't have. It's that's how they catch them too. Yeah, they basically just drive around and pick up the signal.
Host 1 23:41
Here were back in the day, when they when people used to do that with Wi Fi. They wouldn't go around searching for Wi Fi with their little devices.
Host 1 23:48
Oh, was that? Was that called?
Host 1 23:51
Or driving? Oh, yeah. So wore something. Yeah, I can't remember what was called it used to be a thing.
Host 1 23:59
Like, was it? Yeah, it was called wardriving. Yeah, well, you drive around searching for open open Wi Fi spots.
Host 3 24:06
Maybe. Did you guys do you remember? I guess I think it was like 2012 or something like that. That's so
Host 1 24:10
Long ago. Yeah, exactly. Oh, dude shows my
Host 3 24:13
Memory. But Austin City Limits they there was something about them giving Wi Fi hotspots to homeless people. So that they could cover the area with Wi Fi hotspots.
Host 1 24:28
Just like tag them with a
Host 3 24:30
Pond. You know, and the thing is like, I don't remember if that was like an Onion article. Very very well could have been but I thought about that. I was like wow, that sounds like a terrible idea. The trend gun that has those tags. Oh gosh, that's terrible said oh, there's there. Okay, next topic. What is the next?
Host 1 25:02
It's? So earlier this week, I was talking IRC about Oh, someone asked, What's the difference between VSS? Vdd and VCC?
Host 3 25:11
The the notation on schematics, yeah,
Host 1 25:13
The notations schematics. And I thought it went back to basic, just old connotation, and then just everything got kind of, you know, like, they tried to make a standard, and then it just got all blended together. Yeah. But Stephen, actually went in his old art of electronics book, art of
Host 3 25:35
Electronics, Second Edition rate book, amazing book, I have it in my hands right now. Or what's Oh, it's in Hill, this book. If you don't have it, by the way, it's always well, I mean, you could probably get the second edition for maybe 3040 bucks now.
Host 1 25:47
Yeah. So please read passage. From Page 76. I
Host 3 25:52
Think it is, I believe it's not give me a second guys I'm flipping here is page 62, which is in the transistors section of the book. Let me let me read an excerpt here. Voltage between two terminals is indicated by a double subscript, v, v is the base to emitter voltage drop for that instance. So we've dealt with VBE a whole lot. But here's where it gets into the VCC stuff. It says if the same letter is repeated, that means a power supply voltage VCC is the positive power supply voltage associated with the collector. VE is the negative supply associated with the emitter. So VSS and Vdd, would be most fans.
Host 1 26:39
Yeah. I also thought it might have been back from when would analog radios would have different voltage levels? Yep. This from batteries? Yes. And this was back when a D or C cell. Were not like a D and C cells that we have now. Right? They were completely different voltages.
Host 3 26:58
Yeah. Well, in most tube stuff, you normally have four or five different voltage taps, and they're normally letter later letter ABCD. But when tubes are run on batteries, they were labeled by the battery name, C, or D, or whatever that was. And in fact, they used to, even before that, they called everything ht, which stood for high tension, because the line was at tension instead of voltage. Terrible. So yeah, if you ever see a schematic with HT written on it, that's the power supply.
Host 1 27:33
I came up with my own. Okay. volt in whole volt out a hole. So VI, H and VOH, which will even further confuse people because on digital data sheets, that's voltage in high and voltage out hi.
Host 3 27:49
Oh, yeah, extra work for digital levels. Oh, fantastic.
Host 1 27:53
Yeah, acronym overloading.
Host 1 27:54
Yeah, let's go ahead and do that. What happens
Host 3 27:57
When you have different voltage levels? Like three three and five and one eight and two, five? Ah, vi h three, three, no. VIHHV
Host 1 28:06
Host 1 28:11
Just keep adding letters.
Host 1 28:14
For you say like the highlight your five volt and three volt one is just out voltage out the other ones voltage, higher outs.
Host 3 28:25
I'm surrounded by digital guys. What do I do?
Host 1 28:29
Oh, no, no, if you ever want to go in more down like digital notation, yeah, one's a one. One's a super one. Super one in one, two.
Host 3 28:41
We should just get rid of positive voltage and ground and just everything is ones and zeros. That makes
Host 1 28:46
Sense to me. Or twos or twos.
Host 3 28:49
Okay. What am I gonna do?
Host 1 28:54
Or you can just call it multiples of what your normal rail is.
Host 3 29:00
So Vive is not a multi,
Host 1 29:02
DCC is 3.3 volts 3.3 times your multiple is five volts. O Hara. So it'd be VCC. So five volt would be labeled Vcc times was 1.5, something like that? No. These are terrible idea. This, this winds we have the difference between imperial and metric tire sizes. It's kind of random. But whereas, like when you look at an imperial tire size, it's like 30. It's a 30 which is like the radius or the diameter. And then our for I guess it's just the like goes right in the middle. But I think it means rim size 15. So do you have a 30 inch tire on a 15 and then a dash and then the width of the tire right? Was which as a metric sizes is like some number It's like 200 something. And it's that and then a ratio number that you have to calculate. That's the difference between the diameter and the width. Minus like the wheel size.
Host 3 30:10
Host 1 30:11
Yeah. What's wrong with them? I'm like, Sure, cool metric is great when you have to, like measure stuff, except tire sizes.
Host 3 30:19
That's interesting, because they usually beat everyone else in or not everyone else, they usually beat us. In terms of simplicity.
Host 1 30:26
Yeah, Imperial sizes for tires are way easier to look at.
Host 3 30:29
Here's the thing that actually, I think when it comes to the Imperial metric, conversation, Imperial, you don't ever actually use the fractions, you just memorize them. Whereas with, with metric, you actually like, you know, five millimeter, the next one up is six millimeter as opposed to five eighths. The next one is 11 sixteenths, like you just memorize that the next one is 16. You don't actually divide 1116. Now in your in your mind. Yeah. So like for mechanics and things like that, it just it comes second nature, because they just memorize the next one is there so
Host 1 31:02
I can just reach my hand in my tool bag and pull out a nine sixteenths
Host 3 31:07
BS? We're getting a bad and I'm gonna fill it with a whole bunch of tools. You got to pick up.
Host 1 31:15
You would just put a nine sixteenths in the bag. That bag forever. Oh, that's great. I'm actually forgot to mention on the FCC stuff. Yeah. Since we're having this increase in background radiation. We could harvest it probably easier to. I've seen that done. Yeah. Around well, actually. RF energy harvesting. Yeah.
Host 3 31:41
You have to have like a wicked broadband. Antenna. Yeah.
Host 1 31:45
How much power can you get from that? Not a
Host 1 31:47
Lot. Not a lot. But it's there. It's free energy.
Host 1 31:53
You to like turn on a light bulb or something.
Host 3 31:55
No one had to turn on a light bulb. Now you could
Host 1 31:58
Maybe light a little tiny LED? Yeah, something like
Host 1 32:01
That. Maybe not light bulb and led, maybe
Host 3 32:04
Harvest enough of it for a really long time, then you can turn on a light for like,
Host 1 32:09
For like five seconds. Yeah, that's actually
Host 1 32:11
More stuff I'm kind of wanting to try to do is do energy harvesting that way? Well, you store energy. It's been done a lot in salt. And solar is stored energy for a long time and then transmit for a short period of time and then go sleep again. Yeah, it's basically what the rovers on Mars do. What satellites do but it's not really a thing a lot of makers explore is basically power. Power Management, low power management. And actually, Dustin did that for his CubeSat CubeSat.
Host 1 32:47
What power management Yeah,
Host 1 32:49
Whoa, whoa. Forgot about college? Oh, yes. That was a while ago, it's like eight months ago,
Host 1 32:55
I've been trying to forget about about that. That was like only six months ago. Yeah, it was about six months ago,
Host 3 33:01
I actually played around with with the concept similar to that in a previous life, I was designing vibration sensors. And vibration itself is energy. And so I was designing a little circuit, that it clipped onto the machine that it was monitoring, it would steal energy from the vibration, it would fire up an MCU it would read the vibration, and then Wi Fi, kick it out, and then shut down and steal more energy from the device. It was monitoring. And you never had to run conduit and power to it. It just bam. Didn't work. It didn't get super far down the design line. The managers didn't want to go that route. But I started napkin mapping it and it would have worked. There's enough energy and vibration to steal it. And there's some there's some other companies have done similar things.
Host 1 33:51
This reminds me of all the people that think putting like energy harvesting in roads. Yeah, we've seen that. Basically like the floor, the road flexes, we've talked
Host 3 34:01
About these kinds of things.
Host 1 34:04
But this is like, I think they want to put them in like parking lots and stuff. But it's like you're not Yeah, get the energy from somewhere. So you're stealing it from people's gas tanks.
Host 3 34:18
Host 1 34:19
Flexible roads that like their kinetic roadways, I think it's what's called. And basically you drive over them or walk on them, and they flex and they push a little spring down and moves a little thing and you get energy.
Host 1 34:30
Again, similarly to the solar roadways. It sounds way too expensive to be even useful. And it's and
Host 3 34:35
It's a ridiculously inefficient way to get power from fossil fuels. Yes. I
Host 1 34:40
Love the way you use fossil fuels.
Host 3 34:43
I think it's worth mentioning because we seem to be fairly cynical about renewable energies. We are absolutely not. Well, we're not at all. I think we just want them to be done in a practical, practical manner. Yeah, like the whole idea that a Prius is super energy efficient. You You still have to charge it from something that burns fossil fuel. It you
Host 1 35:04
Still have to build the batteries, which requires a lot. Yeah, I mean,
Host 3 35:07
Host 1 35:10
Yeah. Well, the good thing about electric cars, though, is just because you have to power them from fossil fuels, doesn't mean that's a bad way to go about that, right? Because a, let's say an oil power plant or a coal power plant will get like 60% efficient at extracting energy from fossil fuels. Whereas your car is only 30%. Right? Right. So yeah, so first of all, your power is more efficient that your conversion. Yeah. And then your electricity to back to rotational energy is like 99% efficient. Maybe not that high. But it's Yeah, electric motors are very high. Yeah. So let's say 90%. Yeah, that's probably a fair estimate. And so yet, so instead of 30%, you got 60%. And then 90%. Of that you can recapture it's better, way better. It's,
Host 3 36:02
It's better. But it's not. It's not 100% renewable energy was the point I was making.
Host 1 36:08
Yes, yes. Yes. Jack kinetic roadways, officers stupid idea.
Host 3 36:15
A whole bunch of plungers with solenoids, and magnets in it?
Host 1 36:19
Yeah, terrible idea. Can you imagine maintenance on that?
Host 3 36:24
I would bet it would be maintenance on a roadway. The
Host 1 36:27
Only the only maintenance on a solar roadway. Besides fixing the glass when it breaks, is you have to clean it. Yeah, keep it clean. So you're
Host 3 36:35
Still in and when you're when your power electronics go out. And when things break. Like the actual copper connections and things like that,
Host 1 36:44
Along with I'm talking about like general like not failure maintenance.
Host 3 36:48
What if someone gets in a wreck and just destroys an entire section of
Host 1 36:53
Driveshaft drops? takes out a mile and stuff? No, no, just the whole the the just the like the making? No, no, there's still no moving parts in a solid roadway, though. Correct. I kinetic roadway that's got a lot of things that move. I can't imagine like doing well. Just like sand. Just gets in all that stuff.
Host 3 37:22
I'm thinking about sand.
Host 1 37:23
I hate sand.
Host 3 37:27
Yes, it just, it's an idea. And hey, thumbs up to somebody who's coming up with ideas but it's just doesn't seem very practical man.
Host 1 37:36
Honestly driving around in Houston, like how bad our roads are, and then trying to complicate that even further just just puts a sour feeling. And
Host 3 37:45
If we put Wait, if we put these these like little plunger things that generate energy and all the potholes in Houston, Houston would generate so much energy.
Host 1 37:55
Like a million of these things. Yeah. Ah, okay. So on Tuesday, I saw this really cool Crowd Supply called the arrow scope.
Host 3 38:06
Host 1 38:09
It will at first glance, it looks like one of those like cheapy little like, little scopes that you like USB soul scopes that are completely worthless. So this thing is a wireless version of that. Oh. But what's cool is, it has Bluetooth, and so you can connect to your tablets. Okay, and so when this thing's about the size of a large pin, okay, and then plus your phone, you have a scope, and it's got some decent specs, 100 megahertz. bandwidth. 500 million samples seconds, okay. Plus minus 40 volt blah, blah, blah, blah. 10,000 samples sampling depth, which is not that great, but it probably has it has stored locally and then push it up over Bluetooth. How long
Host 3 39:01
Does the battery last than this thing? It must just chew through batteries.
Host 1 39:04
I don't know. It's 10 meg impedance bubble. But the cool thing this would be useful for like trying to fix a deer feeder out in the middle of like West. You know, West, Texas you're working on on like an oil rig where you can't bring your fancy HP scope.
Host 3 39:26
Yeah, or your car broke down and there's something you need to look at in there.
Host 1 39:31
If your car broke down, no, nowhere you probably not going to get it working with this.
Host 3 39:37
If you're in the middle of nowhere and you want to figure out how your car works, yeah. Then you can do
Host 1 39:42
It. Because I'm the one thing I think you can use your scope for when your car cars broken would be for retiming unless it's like Canvas but then now you're not going to fix that. No. That thing yeah without replacing parts. is to figure out timing. And then it'd be cheaper and easier just to have a timing light. And even modern
Host 3 40:05
Cars are in the middle of nowhere and you want to see how much noise is on your your line? You can your power line, you can do that.
Host 1 40:12
But I think it'd be good for, like ham radio, that kind of stuff. Yeah. The I think also it's it kind of limits stuff with only 100 megahertz bandwidth. Because you got things a lot,
Host 3 40:26
You can do a lot with 100. You can do a lot
Host 1 40:28
But if it could do like, let's say five gigahertz, which is that's that's pretty high. But then you can do telecommunication.
Host 3 40:40
You know what? I bet you they have their own custom
Host 1 40:42
They do they have these like handheld like, ginormous ones. Like, like Fluke made?
Host 3 40:47
Yeah. Huge ones that cost an enormous amount. Now, I guarantee they have those.
Host 1 40:52
Yeah, but that's just an example. Yes. Well, I thought of.
Host 3 40:56
Yeah, no, it's I think it's super cool. And do you know, in general, what
Host 1 41:00
The price point or one of these would be? I completely forgot. We might have to
Host 3 41:05
Look that up. Because if this was 150 bucks, yeah, it was about, say, if it was around 200 bucks. That's totally worth it. And especially like, if you're on your desk, and you don't feel like busting out your scope and getting probes and doing all that jazz. And you could just have this sitting right there. That's kind of convenient.
Host 1 41:21
I actually felt the same way. When I had to bust up the saili. DLA today. Yeah, I'm like, oh, man, I have to go with the bench and pull that up and set it up on my bench. And then I put it all together. I'm like, Okay, that wasn't that bad. There's just one of those like, yeah, just like, I don't like spaghetti wire. Yeah, all over my, my desk. So
Host 3 41:43
There's been multiple times when I'm repairing customer gear, where I keep thinking in the back of my head, I was like, Man, I need to throw this on my scope. Because I know I'm gonna find some with the scope. And I'll just like, No, no, I'm just gonna keep going and try solder and things and try, and I'll get like an hour down the road. And I'd be like, I gotta get this scope out, you know, eventually, just like, you have to break down and actually do it.
Host 1 42:05
My favorite is because you're in between me in our electronics bench, Steven. And now like, if I need to use like, the big power supply on the bench. Yeah, I'll like daisy chain stuff over so I can actually have it on my desk.
Host 3 42:20
And a lot of times, I'll just be staring at my computer screen and there's a cable that starts draping over my lab. Like I got, I got to access stuff. I'm like,
Host 1 42:29
I'm hoping that the new shop, I want to set up a bench computer that we can that you can remote into your desktop computer. So you can have all your programs there ready to go. And that way you don't have to do you don't have to copy stuff over. Yeah, that's all that's the biggest pain of having a bench computer is having to make sure that your environments the same for compiling making sure all your codes over there correctly, making sure it's codes up to date. Right, like an old version. Yeah, that's pain. But no,
Host 3 43:03
We'll just push our screens over.
Host 1 43:04
Yeah, push the screen over. Yeah. Cool. Yeah. You have anything Dustin? Nope. I think is it all right. No, sign us out. Sure. Stephen, you have anything you did? Come on. No, I don't got any
Host 1 43:23
I'm your guest, Justin holiday.
Host 1 43:26
What was that was the macro fam engineering podcast.
Host 1 43:30
Oh, okay. Do that last time? Yes, you did. And that was the Packer fan engineering Podcast. I'm Dustin holiday,
Host 3 43:39
And we were your host even Craig and Parker Dolman. Take it easy, guys.
Transcribed by https://otter.ai