On this episode, Stephen talks about his new bias test system hardware and software. The bias test system is a purpose built test hardware system!
Parker makes small progress on the SDR Wagon Project and Stephen officially launches his new blog Analogeng.com.
Stephen creates a new blog and starts documenting his projects and Parker pitches a SDR based car radio.
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 and Stephen recording over Skype.
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!
Hello and welcome to the Mac fab engineering podcast where your hosts Parker, Dolman.
And Steven Craig, this is episode is episode 123.
So, Steven, you're in Colorado now.
Yeah, we're gonna have to learn how to not step on each other's toes, even though immediately, just right before we started, we were like, oh, we'll be fine. We're not gonna step on each other. I'm up in Colorado. Now. This is the first separate podcast now.
I cool. So we've been up to seven.
Just trying to get settled in and just finished my third day of work, which is a lot of fun. We're kind of getting me up to speed on a lot of things. I'm spending about half my day out on the manufacturing floor, and half my day designing new sounds and
things. new sounds. All the beeps hopefully.
Oh, yeah. Every I will possess all of them. They will be mine. Yeah, no. So yeah. So it's just, I think I'm going to be trained up as a machine operator, but not to do that full time. Basically, the I think the guy who is running the main machines is he's gonna, he's having a kid soon in September. So they need someone else to run their picking plates and their stencil printer and stuff. So I'm getting trained up on that
makes sense. Yeah. So
we'll certainly talk about it in the future. But I've got some I'm already working on my first product out there. And I don't know exactly. I haven't talked to my boss yet. What I can say on the podcast and whatnot, but certainly once the product is out, we can talk about it. Cool. Cool. Yeah. How about you
been working on my blog a bit. Got that rolling. So I've been updating that, you know, we joked around like, updated like four times and then go dark again for another year. Had that turnout. I've been posting about two to three times a week now. So congratulations. Yeah. So Matt, like eight updates or something like that since I said I was going to post more. I think the main thing is I've been posting more about like the other stuff. I do not just electronics, so like the three wheeler project in the jeep.
Yeah, yeah. I've certainly been seeing getting a lot of text with three wheeler engines running and things. Yeah.
Not to post that video on YouTube. Yeah, it's pretty great. Yeah.
And you you found that there's a gear with a missing.
Yeah, with a missing thing. Still run still runs? It just makes an awful racket.
Yeah, yeah. Well, eventually, I guess the the teeth all just grind themselves to dust. Yeah, unless you replace it. Yeah.
All the replacement gear is like $5. So I bought one. It's so weird on price of parts for that. That machine.
Yeah. What was it an ad for? ATC? 110. Yeah, engine three wheelers? Yeah, it's kind of crazy for something that old. And so it's sort of obscure, the parts are really cheap. Yep.
Yeah. Unless you need like, a cosmetic part. And then it's like 500 bucks.
Yeah, yeah, of course. And those are the things that break and people want to replace
exactly like fenders and stuff. Yeah. Other than that, had an article finished the key parts of Arduino. That was like the talk I gave a couple months ago at our hardware meetup. And it's like how to integrate the Arduino platform and your product if you've been prototyping with the Arduino. So I don't think it's out yet, but it should be soon.
Probably in the next by the end of this week.
Yeah. Should be that.
I bet you that's gonna be a really popular one. Because there's, there's a lot behind that. Even though it's it's fairly simple, like, just having somebody like step you. That's that's really valuable.
Yeah. And I basically go through like, you know, I break the Arduino Uno schematic apart, and we go, okay, this does this, this does this. This is something kind of funky. You know, don't do that.
Do you, actually, so that's a good question. Do you have anything where you like, you don't need this don't include it.
The power MCSE circuit? You don't really need that.
You're talking about the one where it flips it switches in between
USB power. onboard? Yeah. Yeah. There's a much much smarter ways of doing it. How they did it is unique. I wouldn't say it's the best way though.
Didn't they just do it with a P MOSFET. Or something like that P MOSFET.
Driven by a op ed In a comparator setup?
Oh, yeah, yeah, yeah, it's kind of just missed the line and then it switches over if it needs.
Yeah. If the voltage on DC is high enough decent power. Yeah. It's kind of interesting. It's the thing is most products don't need that. Because they usually have one power source. So yeah, just throw it out.
Right, right. Yeah, it is. It is fairly unique to that kind of
platform. Right? Yeah, development boards have a lot of stuff on it that you don't need in your product, always. So that's what it looks like, you know, is your does your product have a need USB? Does it need the bootloader? Stuff like that?
Yeah, if it doesn't, that's that's, that makes it really nice. Yep.
And then I started working more on the Jeep. Jeep Prop was what it was called. I don't know, we've really talked about too much on the podcast, but it's like the Jeep computer to control the relays and stuff. Inside the Jeep, like
the fan, you know, I I think we mentioned that a long time ago on one podcast where we were talking about the old school diagrams. Yeah, automotive diagrams. Yeah, yeah. Yeah. How's that coming along?
Pretty good. Um, I was going to use thermocouple thermocouples, for like, sensing all the temperatures. But I decided to not do that and go with what automotive manufacturers use, which are just an automotive temperature Center, which are thermistors, NTC, thermistors. And I haven't really used these too much since college. So I kind of wanted to talk about like, what's the best way to read a thermistor for the microcontroller. Like to get a temperature reading? Because they're nonlinear responding devices. Right, right. Yeah. And, even worse is the sensors I ordered or like eBay specials. And so they don't come with datasheet. So you don't know what the curve is anyways.
Oh, oh, okay. So they so you're, there's a lot of curveballs that are thrown in it. Oh, yeah. Kind of thing. Okay. So are they positive coefficient?
Negative? Negative? Okay. Yeah, the NTC.
And, oh, yeah. Done. He said. So you said, Well, okay, so so they have some kind of nominal resistance. And you know what that is, right. Yeah. So
what I was gonna do is when I get them, I'm going to basically make my own chart. Yeah. Is dunk the sensor and water dunk my burning thermometer lectric. Brewing thermometer that's down that's like has a precision of point one Celsius. Put that in the water. And just like slowly heat the water up? And just, you know, do from like zero to 100 Celsius over maybe 10 degree increments? I don't actually good enough.
Yeah, yeah. And actually, you know, what would be kind of good. Macro fab has that vacuum oven? You could use that as a process of and characterize the curve?
Yeah, that's actually a really good idea. That's actually way better. I didn't what I just said.
Well, and you know, what I would do in that in the situation of that resistor, what I would make is a constant current device. So you're always driving a known fixed current through it, especially if you could, if you can have the constant current driver inside the cab of your car. So it's at a more reasonable temperature, such that you, you know, exact so such that the current won't vary. You can have you know, the cab of your cars at 175, or whatever temperature.
You just get in it. And Houston, it's like 384 Celsius.
Right. Yeah. I saw a video of a guy who cooked a brisket in his car.
Like foil?
Yeah, yeah. But okay, yeah. So so if you put a constant current through the resistor, what's what's nice about that is you cancel out. Any variability? Well, not any but most variability. And you get a known fixed self heating, such that, whatever. Yeah, yeah. So you cancel all that out. And then what you're left with is in the equation, the only term is what changes with temperature? Yep. It's sort of it's sort of what you're doing with an RTD basically,
yep. Yeah. Yeah. Yeah, cuz the the first method you find that people use are like the voltage divider method, which is you do from like, you take the, you basically put the thermistor as like the bottom leg of your voltage divider and you put a analog ADC in the middle and just read the voltage change, which is you just get a nonlinear result, basically, which is fine. If you have a chart.
Yeah, you just have a lookup table and linearize it in a in a, in your micro.
Yeah, but the thing about those, it's not very sensitive usually. Is it down?
Yeah, it depends on what the the temperature coefficient is.
Yeah. And, and you actually gets worse as you brought up the self heating aspect of of these memristors. And that's actually a big problem with these. That setup is, as the temperature changes, its self heating changes. So right, yeah, right.
You know, have you ever heard of, probably, and I think I'm mispronouncing this I might not be. It's called a wine bridge W stone, ein? Yeah. Like it's the it's the four, you can put four elements in a in a kind of a diamond configuration and somatic.
It's two voltage dividers, and you read from the Centers both?
Yeah, that's right. So sweet stone, if you if you if you did that, where you had both sides, or both dividers with constant current on it, and then you put a differential amp in between there, you can actually cancel out a whole bunch of extra noise. Yeah. And you can, but I mean, let's be honest, you're putting this in your Jeep. You're not caring too much about like, you know, reading super high precision or anything. Yeah. But if you wanted to do something more fancy with it, you could, you could do a Wheatstone bridge or whatever.
Yeah, I think that's what they're called. So there's that. And then I started looking up just like NTC, thermistor, ICS, to see what's out there. And maxium, of course, makes something.
And they probably have really great diagrams, and yes, and they're there,
they cost their weight and gold. But I wonder if any maxium like engineers, listen to us.
If you do, please write in, give us discount, whatever the whatever the address is, what podcast@gmail.com
Yeah, the Mac 6682 M UA, I was looking at that. And basically, it's kind of like the voltage divider method, but it's got a but how it drives the circuit, it only does like 10% power or duty cycle on the thermistor. So it doesn't self heat. It's like point 0015 Celsius, self heating or something like that. So you don't have to worry about it, and 10 bit, and then you just spy the data over. Now, it doesn't fix the nonlinear. So you still need to like have a lookup table. But that's the thing about all these methods, you still kind of have to have a lookup table to characterize your thermistor. It's not like a It's not like a thermocouple. Which this voltage is this temperature.
Yeah, yeah. Yeah, for sure. It so there's actually so that, above and beyond the lookup table, though, the lookup table is is fantastic. And to be honest, for like singles and one offs and things like that, it's probably the best because it's really easy to do, you just take data and and you get really accurate results with it. But in a like production sense, it kind of makes it a little bit more difficult because you just spend so much time calibrating every single unit, one of the one of the nice things to do is spend a little bit more time take, say 10, thermistors, and characterize each one of them into their own lookup table, throw that into Excel and create a polynomial average of all of them, yeah, averages all of them, and you can calculate it on the fly. And then you can get your data on any thermistor that you throw in there. And it just takes a few extra clock cycles for you to run. And to be honest, when I've done that in the past with this kind of situation, you really only need maybe like a third or fourth or order polynomial, which, you know, when we're talking about temperature, most of the time, you don't need a sample update more than say, once every few seconds. Yep. So your processor, even even an Arduino would have plenty of time to hammer out a bunch of power polynomials, you know? Yep. So that's, that's one option. Yeah. So yeah,
I think that's a good, good starting point. I'll probably use this Mac 668 to chip and then see where that goes.
Yeah, yeah, that'd be fun. You know, every time I've ever worked with any kind of temperature circuit, what I've found is the amount of time you spend getting the schematic and the hardware and the layout just pales in comparison to how much time you spend calibrating the damn thing Oh, yeah, like getting data points to design a temperature circuit. But good God, you spent so long getting it right, you know, when you actually have the circuit? Yep,
I think I think you're right is build the circuit, and then pop the the thermistor inside the process oven and then just set the Senate to room tamp and then just increment every couple degrees. And let you know, let warm up sit for an hour. And then look at your reading and be like, okay, and build the chart out that way.
Yeah, that's that's probably the easiest and and that that oven is, it has generally pretty good accuracy. If we originally bought that oven for what was it? Taking care of MSL levels on components drying them out, so you can pull it back on? But you can use it and also for advanced curing of your days and stuff? Yeah, boxy? Yeah, stuff like that. But it actually holds a fairly decent temperature. So I think you'd get good results with it.
Yep. Now, should I pull a vacuum on it or not? I don't think I need no, no,
don't pull a vacuum on it just yet. Do it do it straight. Because I, you know, I don't remember my equations, but I bet you pressure has something to do with it. You know? Yeah, probably. So you probably screw everything up. But you could make, you could make a three dimensional like matrix polynomial that is temperature and pressure dependent on and pressure dependent.
Thing is where this thermistor is gonna be used, it's going to be under pressure not in a vacuum.
You know, it's good to get,
you know, it's hooked into like, let's say it's hooked into the oral oil, oil port on the Jeep. That's, you know, anywhere from 10 psi at idle to 60 psi driving on the freeway.
So that's true. Yeah.
But it's in like a, it's in a thermal Well, right. Yeah, it's in the stainless like, case. So I'm like, it's probably not exposed to that pressure. So
well, yeah, I doubt it would be. Also I don't know. Yeah, I don't think that those components are great with getting liquid on them. So So I think, yeah, just just doing temperature, ignore pressure, or just do you know, whatever. However many pressures are at sea level.
One atmosphere. One. It's like that joke on Futurama, where they have a, you know, an fi drama, they fly around the spaceship. And they're fishing and they get sucked under the water by a giant fish. And they're sitting on the seabed, and they asked the professor who built the ship, you know, because they're, they're under tremendous pressure from from the sea at the bottom of the ocean. And they asked the presser, how many how much pressure can the ship take? And they're like, Well, it's a spaceship. So somewhere between one and zero atmospheres
the tongue in cheek science stuff in that show is just fantastic. Exactly. It lands home with guys like us. Yeah. Very cool.
Yeah. I wonder I wonder if the space shuttle went underwater? How much pressure you could take?
You know, it's it's rated for impact, but probably not for continuous pressure.
Maybe? I don't know. Maybe a NASA engineer can tell us how much how well a space shuttles a submarine.
Well, of what I've what I've read and found out about the the spaceship it or the the original shuttle, it didn't really fly very well. Like it wasn't really meant to fly. It just kind of like felt like a brick and it had some control surfaces. You know, they basically like they got a ton of speed coming into the atmosphere, and they would just pull the nose up real high right before landing just to get a little bit of lift, you know, to basically not slam into the ground. But I guess it's kind of hard to design something that's both a spaceship and airplane.
Well, they call that a SSTO. Which is that I think what's SSTO stands for as I google this, yeah. On stage to orbit. So what would you call something that's a plane? A submarine and a spaceship?
A triple threat
a Triple Threat single page failure anywhere nightmare. That's what nightmare. Viruses is questions on on Reddit. The is it really a space shuttle is a good submarine. Really. So that the post links
but the thing is like it's supposed to keep Things in as opposed to think keeping things from getting in. Yeah, yeah. Exactly. The whole point. Exactly.
Well, the answer might be a very bad, you know. Summary.
Sure, sure. Although the, you know, the astronauts they train underwater in their suits. So they're their suits are rated for some kind of pressure. Yeah. external pressure, I guess. Yeah. Cuz I mean, you've been done the NASA you ever seen the pool down there?
Yeah. It's like the deepest pool in the world.
Yeah, one of them, though, for sure.
Unless you call like the Atlantic Ocean up pool? I don't think anyone does, though. Okay, Steven, what are you been? Yeah, besides work?
Well did honestly just trying to get everything settled in here. But so the thing is, you know, just because I'm in a temporary place right now until I can get, you know, actually purchase a home. I've got a little bit more time to, you know, be on the computer and do some more conceptual design stuff. And I have actually been looking at the SSPs. I have that schematic pulled up. And I haven't made any changes, but I've been looking at it.
Oh, no, no. So I've been working on that compressor IoT project a little bit. And I'm like, this is about looking at schematics and whatever side tangent, and I put I did some code on it last night. I'm like, Huh, why am I not? Why is the microphone not working? And I'm like, wait, we might have talked about this on a previous podcast. So I started looking like podcasts that we were talking about the compressor IoT. And looking at the show notes. Sure enough, I forgot to I, I remember the op amp. I put the positive, negative backwards. Because I didn't I didn't. That was like that was way early on. Yeah. It was like episode 70 or something like that. And the podcast title is reverse biasing op amps. No, I didn't do it. I just didn't remember. And because I didn't make the change on my schematic. I'm like, Why is this not working?
Gotcha. Nice. Yeah, well, with the SSPs schematic, there's, there's a lot of things that I want to keep about it, because I like chunks of them and a lot of things that I want to change about it. So I'm looking at changing the output architecture. Just we're really actually so big, we would discuss this, you know, a few podcasts ago. But if the circuit works, everything does what it needs to do. But now what I'm trying to do is figure out like, how the hell do we get rid of this much heat? And more about it is like, how do I distribute the heat? Because it's very easy to put 700 watts of heat in one component, but it'll never survive. So how do I take 700 watts of heat and divide it between five or six or 10 components? You know, that's kind of what I'm looking at. And in fact, if that's what, if you look at like textbook examples of like a power supply or anything, really, a lot of times what you'll see is something that's really simple, and it gets the job done. And then you go look at a professional version of the exact same thing, like a professional power supply. And it's just completely dotted with tons of other components. And and, you know, if you've never seen that before, at first, it comes off as really confusing, cuz he's like, well, this doesn't look anything like the textbook example. But if you start stripping off all those components, you it is the textbook example. All of that extra crap is there for a reason. And it does something that you know, is above and beyond just like pen and paper make it happen. So that's the point that we're at right now. We've done the textbook thing we know it can deliver a crapload of power and we know that it you know, it can actually do that. But now we got to say like, oh god, how do we actually control it? How do we actually like, keep the heat where we want it? Yeah, so
I actually just thought of the tagline for the SSPs Oh, is that it's super simple power supply the entropy greater.
Yeah, chaos.
Chaos. Chaos is the exact opposite thing.
Well, yeah, okay. Orderly chaos. Yeah. Yeah, so So the essence
will be the sole reason why we have the heat death in the universe.
I apologize for ending the human race by designing this. Everyone. Yeah, this is a pre apology. But as soon as I have the some more information, I'll certainly pass it along to everyone and people can take a look at it and criticize me for my bad design choices and
we should build and build it.
I have it here actually. So it's in my storage facility. At the moment, but I kept it at the front of the storage facility. So I can go over there and grab it.
The best thing is when we put it in your truck, we put it under everything. Yeah, cuz we knew everything could handle that. Yeah, cuz it was in this really, you know, sturdy steel box. And so we put it down and piled all of Stephens belongings on top of it.
can handle it? So another thing actually, I think I've talked about this a little bit in the past, probably not much, but so I have a, I have a project that I actually purchased from a guy, actually, you know, I don't remember where he is. It's somewhere in Europe, but it's called the micro tracer or the new tracer, you tracer three. Yeah, the tracer three new traits, or whatever you want to call it. We
talked about this on the podcast, yeah, long time ago.
So so this is a device that a guy designed to test vacuum tubes. And it's a really nifty kind of device, it's a USB connected device, where you, you have like a GUI on your computer, that you can configure this thing to test. Basically, any kind of tube out there. And and testing to is, when you're designing, it actually helps a lot to know what the characteristic of the tube is, to actually have a transfer curve and see all that stuff. You know, like, you can do the same thing with transistors, but they their design tolerance is tight enough that most of the time, you don't have to worry about it, even if you're making an amplifier. But with vacuum tubes, it's nice to know what the anode resistance is, it's nice to know, you know, what the what the the screen current and all that stuff is. So this, this micro tracer will actually do all of that work for you. And you can it'll plot the curves on your screen. It's a really kind of cool device. So if anyone wants to check it out, the website is dos for ever.com. That's DLs, the number four ever.com/you tracer three. And what's what's cool is the guy who designed this has his lab notebook, he calls it, it's his blog, basically. And he goes through the entire design phase of everything he's ever done on this thing, and he keeps adding to that blog. So there's a lot of really cool information. So if you want to see how he got down to like, the nitty gritty details of how he like, uses, like this really interesting pulse design circuit that will like instantaneously throw the device up to like 400 volts, read a whole bunch of currents and then like go back to safe mode, he has like all this all this really cool stuff that he did, and all of his like charts and everything. Regardless, he has a couple of upgrade circuits that I'm going to be implementing into it soon. Previously, this device was not able to measure grid current, which grid is analogous to a gate on a MOSFET or a base on a BJT. And with you know, with with a MOSFET, you don't ever want really want current flowing into the device into the gate. And on a BJT you want a very known amount of current flowing in. But on a tube, there's virtually zero current flowing in until you get to a certain point and then a ton of current flows in and and to be able to plot those lines is actually very useful for a handful of applications. And until now there really hasn't been a really good way of doing that other than like, you know, throwing a resistor on there, putting on scope and just kind of guessing but but he's got an upgrade to this device now that has a pretty cool little circuit that basically tricks the thing into being able to read grid current so but above and beyond all of that I kind of want to design a news new PCB that that's like a little daughterboard attachment that has all of the different tube sockets on it so like a seven and eight and a nine pin tube socket, but I want to have a whole bunch of rotary switches on this. Well nine rotary switches each pin on the tube socket, you can just turn the rotary switch and you can configure it such that if you say you have this tube where pin one is connected to yeah, this pin is you just turn these rotary switches in it realigns everything. So any tube you buy you just turn the rotary switches to whatever applies to that. Plug it in and it'll test that one. So every really cool. Yeah, and it's it's a pretty I mean, it's just a switch matrix basically with
imagining like this giant panel, you know, machine that's like a frame and you like clock like the beginning of back to modern old knobs and all you see is the knobs and the meters going up and yeah,
and I love how his volume control is a variac Yeah. Actually, I should I should I should pull the knob off of my variac that I have and put that on an amp somewhere and such like a monster knob on there. But ya know Regardless, I think that I think that that'd be a fun little project. And these are things I can do, you know, on my computer when I don't have my soldering iron and all my stuff. And definitely yeah SSPs in the in the micro tracer, go check out that website. There's a lot of it's a lot of really cool like ways to interface like digital, all the way too high voltage analog, and then back to digital. Really interesting blog.
Yeah, and his micro tracer, I guess SEC section of that stuff, like has a schematic and I think my favorite thing is his schematic is just like a big brick of symbols. And then he boxes them out. So everything's connected to everything. So it looks like spaghetti, but he has them all segmented out of like, this does this. This is the microcontroller section. So it actually makes it easier to read.
Yeah, yeah. Yeah, actually, you know, it's funny, it's very similar to the Teensy. If you look at the TNC schematic, they just kind of like, you know, slapped everything right in front of you. And they're like, good luck. The only thing is the Teensy schematic doesn't like block anything out. It's just like, everything is there. And the whole schematic fits very nicely into like a rectangular shape. Yeah, it's all just like, well, good luck, you know, using go and figure out what things are. And there's some notes and things but so yeah, I like I like the way he draws his schematics. That kind of
really nice, I guess. marfo time? Yeah,
let's go on the RFO.
So we only got one arm for this week. And it's a product that just came out. Cool and similar to the SSPs but very low power saili just announced their new programmable 128 watt power supply with one millivolt one milliamp precision. Oh, so yeah, it's pretty low, low TuneIn have the power that you can get with that.
One milliamp is not a don't get me wrong. That's that's not easy to get. But you see that more often than one? millivolt? I'm sorry, did I say Milla? Milla amp is is you see that more often? And then millivolt? One millivolts kind of a little more rare. You see? Yeah, point one or point? Oh, one millivolt more often? Yep.
So yeah, this is I was looking at the six, zero to 16 volts and but the thing is zero to eight amps, which is that's quite a bit of power. That's beefy. Yeah. And it's got really low noise and ripple and stuff like that. And it's got remote voltage sensing capability. So you can do this for wire. And I think the main thing is about this connected to computer to and do logging, which is PA Yeah.
It's a linear supply, or is this a switcher?
I don't know. I want to bet you it's in linear because of how low the noises
You know, I but the thing that the thing that kind of like sparks it as potentially a switcher, in my mind is the high current. Yeah, that too. So I, you know, yeah, I would do the eight amps at 16 volts would have a pretty beefy transformer on it. Yep. But maybe it does, you know, so. But actually, yeah, so higher current is, tends to be easier on a switcher, when lower noise is easier on a linear So yeah, if you get the two of them, then you get something expensive.
And this is only 260 bucks. So it's not either one of those.
Actually, yeah, that's not bad. Yeah, but, but 16 volt maximum is a that's maybe a little bit of a downfall. But
But 40 get how guys? Yeah, for digital guys, it doesn't matter. Right. That's the most you really going to use.
But 12 is probably the most you'll use for like relays and servos and stuff.
Yeah. 16 is 16 is nice, because Automotive is like 14 ish volts. Like 13.8 to 14. That's cool, right? Yeah, I was gonna look at this and see if that would be good. Well, I'm gonna wait till Dave Jones gets one and like, you know, rips it apart.
Just shits all over? Yeah.
Before I buy one.
Or someone doesn't. 60s is not that bad.
No. The specs beat the hell out of my current linear supply. So I like the programmability because I want to be able to program like noise in and stuff. It sounds like I can do that with this device.
That's funny. You buy a really low noise supply so that you can put noise in it.
Yeah, we got to see how good your your actual circuit rejection is and stuff.
And actually, I'm curious. So it says low ripple and noise and the figure is less than 350 micro volt RMS. I wonder if that's across the entire range all the way up to 16 at eight amps. Or I wonder if that's like guaranteed 3.3 at milliamps, maybe if it holds that at eight amps, that's awesome.
I would like to see like, maybe something like this, that also, you know how I was talking about like recording, like your sampling your how much power you're pulling, because I've been doing a lot of low power stuff. And I like to see like, nano amp recording. So like it can read nano amps. You know, maybe a Milla amp precision on the current on the on the current control, sure, whatever, because you're not going to control when you're testing, you know, your new device for or not your new device, but you're testing your device for low power consumption. But you want to read low power and monitor like when your microcontroller comes out of comes out of sleep and starts processing, you know, those, were talking about the four 4/4 order polynomial for your
free temperature connotation. Yeah,
your Thermistor it's like you, you kind of want to know that. I don't know if there's a tool out there because it would be nice if you could set up kind of like a DLA. So you're monitoring digital signals, and then the power consumption at the same time. So you can say, hey, when you come out sleep mode, pull this pin high and you go back into sleep mode, pull it low. So you can say, Oh, this is the how the power consumptions actually, you know, you know, working
yet. I don't know if there's like a specific machine that does that. But you could probably trick a handful of machines into doing that with maybe some you know, with a computer talking to
all of them. Yeah, yeah, I think you can do it with that. And then like, run all the machines at once.
Yeah, yeah, exactly. It's
like I have a multimeter that does logging. And I can measure that low. But it's like, yeah, it can also measure a trigger events that I need.
Yeah, I think you would have to set up something that once the trigger event occurs, it would have to start the logging right then. Yeah. And I wouldn't be surprised I haven't run into it. But I wouldn't be surprised if some high end stuff has that capability where it says, hey, you know, once this happens, then start doing something.
I bet you it runs on LabVIEW.
You can make anything happen.
I'm just remembering like, why? Yeah, I was just thinking myself, like, what software have I used in the past that allows multiple machines to talk to each other? I'm like, oh, yeah, I love you. And I'm like, Oh, love you.
Immediately. I don't want to use it. I think we talked about this before, but I'll bring it up again. Did you have to use the NI ELVIS? Oh, yeah. In school. Yeah. Elvis sports that basically didn't work. Like every lab was basically just a troubleshooting lab for the NIH Office. Yeah,
my x speaking that my first my first real big Analog Lab. Yeah, in school. I spent the first lab just basically troubleshooting jumper wires, the breadboard and the cable like the BNC cables. And then I went to Fry's Electronics right after lab after lab and I bought my own breadboard, my own cables and jumpers. I basically bought everything else besides the components didn't have a single problem ever again, ever again.
And knowing knowing you just because I've known you forever, handful of years now, you must have been livid like absolutely fear. Because I know like, the last thing that Parker ever likes is when equipment fails, just messes with enough fails, but just messes with you. Oh, yeah. Oh, that gets you a theory.
I can't say that. I can't stand it. So yeah, I went to bought my own equipment. And like, I show up the next lab with my own stuff. And I'm like $25, and I'm not going to be frustrated ever again. Yeah, and
get an A and actually, we should probably mentioned of what the NIO service is it's like an educational like board system. It's like a brick with a big steel brick with a breadboard on top of it. And it could it could interface to some, like higher level LabVIEW applications on your computer that were meant purely for like electronics education. So it was things like oh, you could you could do like a voltage divider. And like see it on the screen or you know even further it would like to inject a signal in readout like a filter or something like that. And you could you could plot a Bode plot of an actual RC filter on there. Yeah. Although every time My ever did an IRC filter. I swear to God, my TA was like, Okay, if it's a low pass, he would he would let you pass the class. If you could just prove that the signal was smaller at high frequencies like it didn't have to actually look nice, because then I Elvis would never work. No, you're just like, as long as high field high frequency would just be lower than low frequencies like, Well, yeah, it's good enough.
Well, the problem is just those contacts are only rated for X number of things of insertions. And they just were out.
Yeah, yeah, exactly. They were out and you would work for an hour and nothing would work. And then you find out that like, Oh, if I just moved my pin one contact over. Yeah, it works. And it works. Oh, my God, it was
horrible. Mine was I have to go to a jiggle day. To get the work. We had to jiggle a jumper cable. So as it's running, we someone sitting over there just doing this wiggling the cable.
What did you write that in your in your lab report?
I told that to the TA. Because yeah, it's like, it's like this
wired equipment. It's like vibration.
30 hertz, applied to jumper wire three. Yeah.
In the back of our lab at a&m, they had a plastic bin that had all the resistors that you would need for that lab. But it seemed like these resistors had been used for like 500 labs. So every lead like, you would never find a resistor leg that was even slightly straight. They had like 8 million bends in them. So sometimes, I mean, a lot of times, on a breadboard, you have to have a pretty nice straight leg for it to press in properly. But with these holy crap, they would never go in. Oh, it was horrible.
Yeah, that was same thing. They look like they were from the the 50s resistors. And you would have to have a, like, 45th order polynomial to like, write an equation for that leg.
They were just completely mangled. You know, the end, the thing is, like, I would I would look at the business school. And every day, it was like, they would completely redo everything in their bill.
Like every year, they like remodel the front entrance.
Yeah, exactly. And I'm like, holy crap, I paid this much. And they can't even give me a one cent resistor with straight legs. And on top of that, at a&m, everyone was like, super happy because we got all brand new computers one day. No, we didn't get brand new computers. We literally got the hand me downs from the library, the electronics and electrical computer department got the hammer library. It's like, Oh, my God, how much money can I give to these guys?
One time, we got brand new little scopes, and all the labs and I'm like, Oh, this is I actually got to set them up and stuff. And I'm like, This is really nice. The thing is, that's not what the lab needed. We already had really good. They're a little older. But HP scopes that Yeah, I mean, they were like, you know, 500 megahertz HP scopes that had built in delays and stuff. I'm like, why are we getting rid of these and replacing them with basically the same thing, new version Techtronic 500 megahertz electronics that are brand new, where all we need is brand new breadboards and resistors. And cable, oh my gosh, everything else can be the same. Like old scopes are fine. Like I still use my Tektronix 464. It's a fine 100 megahertz scope.
At the end of the day, they all do the same thing. Especially when you're talking about you know, the stuff you learn in college, which, frankly, is you would never push even an analog scope to its extreme. I shouldn't say never but you know, like, circuits one to one, you're not going to push a scope to it to the extreme limit. You might put like a one kilohertz sine wave into it. Yeah, something like that. Yeah. So if you run a lab out there, please treat your teacher students nice even though you know, even though they probably don't treat you nice. Get them good resistors
or just telling the put together like your I triple E department just put together a kit that can buy for 25 bucks.
Actually, you know, would be a really good thing is the very first lab they teach you how to search on Mouser. And they give you like, even though you would pay for it, they give you like a $25 credit and then you go buy all the stuff. Yeah, that would be really practical. That would be awesome
would be really practical. So
we should run a lab one day. That would probably be really, really crappy
would be My TAS had lost all their soul. Then no twinkle in their eyes
their eyes were just entirely black.
Yeah. glazed over. Excellent.
I had multiple TAs who were like, get your bachelor's degree and get out of here. They're like do not go to higher level just don't go oh
well, cool, Steven, you wanna we have any more war stories or we're gonna wrap this
up? So that was the macro fab engineering podcast. We were your hosts, Stephen Craig
and Parker Dohmen.
Take it easy
later everyone. Thank you. Yes, you our listener for downloading our show. If you have a cool idea, project or topics that you want Stephen and I to discuss, tweet us at Mac fab or email us at podcast at Mac fab.com. If you run a student lab, make sure the cables work. Also, check out our Slack channel. If you're not subscribed to the podcast yet, click that subscribe button. That way you get the latest map episode right when it releases and please review us wherever you listen as it helps the show. stay visible. helps new listeners find us
On this episode, Stephen talks about his new bias test system hardware and software. The bias test system is a purpose built test hardware system!
Parker makes small progress on the SDR Wagon Project and Stephen officially launches his new blog Analogeng.com.
Stephen creates a new blog and starts documenting his projects and Parker pitches a SDR based car radio.