Stephen gets an upgrade in his electronics lab with a new multimeter, A Fluke 87V! We break down Stephen’s old meter vs the new Fluke.
Stephen and Parker continue the discussion of the voltage measurement. Can you come up with a way to measure voltage without precision tools?
A custom, open source, DIY multimeter? Parker and Stephen go down the rabbit hole of putting down design requirements and what open source means.
How do I branch into Electrical Engineering?
Is there a macgyver way to measure voltage without a multimeter?
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 a weekly show about all things engineering, DIY projects, manufacturing industry news and MacGyvering electronics. Were your hosts electrical engineers, Parker, Dolman and Steven Craig. This is episode 325.
Are we allowed to MacGyver someone's last name? Yeah, why not? Oh, not McGyver. Verb verbalize. Yes, yes, we are absolutely love verbalizing. But but only in the intro to this podcast.
verbalized allies were just great. That's the right word. That's a real
I gotta look this up now, but not in the way we just used it.
What is the verb, verbalize express in words? Or speaking out loud? Okay, so it's not the act of convert something into a verb? No.
So we even use that word incorrectly. Oh, nevermind. Number three, make into a verb. Oh, okay. Well, we're using the third definition then. Yeah. There.
We can. So can you verbalize? someone's like, I guess it's not a real it's not a real person, either. It's just a fictional character. Right? Yeah. Yeah. Well, I mean, we just didn't I hope everyone understands what we mean by that.
What MacGyvering electronics? Oh, I think actually. That's, that's sort of now we're getting all kinds of weird. But that's sort of one of the nice things about the English language as you can really mess up stuff. And it's still understandable, right? Like, even though that's technically wrong, like, it's, it's something where we can you can just apply the rules in your head and be like, Okay, well, I get what's going on? Apparently, Oxford languages has MacGyvering. And it's okay, well, then you know, what? You all that's been wrong isn't our language. It's just been you and me this entire time.
Alright, so first topic of today.
I got a email. I think yesterday, maybe it was this morning. From Keystone. They said I sign up for their newsletter. I think it's like, once a month as a newsletter, the newsletter that Keystone comes out with. And
it's a really weird newsletter, because a lot of times I'm like, I've seen that part. I've seen that part. We've seen that part.
But this was a part I've never seen before, at least from Keystone. And it is a SMT 2032 coin cell holder. But like
countersunk, I don't know what the term is for these kind of parts, because like cameras, embedded, embedded. But that means other things in our industry.
I couldn't come up with what a term for this kind of part is. It's a part where, because to me, countersunk is like it's like in the material. And this is in material, but goes all the way through the material. So basically, it's a part that is like halfway in the material counter blared down in counterbore. And maybe, yeah, but basically, this is like a SMT holder for a coin cell that you route out like a big opening. And this sits halfway through like half the part is poking out the backside of the board.
Yeah. So on the this this shape that you read out of your board, you put terminals on sides of the shape, and then it's soldered directly to that. Yeah, so basically the entire coin cells held up by these terminals. Yeah, yeah. Perhaps perhaps not the most robust situation.
But if your board needs to be as thin as possible, and hold at 2030 to sell this is probably your best bet. Yeah, that's definitely your best bet because there's um, USB connectors that are like this, that are like half sunk through the board.
When other parts are, like, have you ever seen used parts like this before, not directly like this, but something that comes to mind is we use a lot of the LTS T style reverse mount LEDs, where the lens itself goes into a hole. So you mount it from the backside of the board and the lens fits inside the hole. It's these LEDs are fantastic because they're inexpensive, they're they're actually really efficient. We've been able to reduce the current draw in a lot of our products. And what's nice about these LEDs is since the reverse mount most of the time with our modules and our assemblies were able to replace LEDs if need to be very easily because you
Just pop it off the back, throw a new one in, and it's good to go. Hmm.
So you have used parts like this for I've used, I don't think I've used any of those parts before.
I took a 16 by two character display though, and then routed outward, the bezel part of the board, like where the actual screen is. And then was able to basically mount the screen backwards into the board to kind of reduce the height and
basically make assembly better. So you didn't have to use like standoffs or whatever. For the
for the bosses screw bosses.
So you remember Octo prover right, Steven? Oh, yeah, that's how I melted the screen on it. So the screen is actually like, directly soldered to the to the board and not with like a header and like standoffs and stuff like that. Reduce makes it thinner but also just reduces the cost
of assembly with a like a 16 by two character display, even though we're like after that I found some character displays data actually are designed for more like that. They like sound like you did with Yeah, yeah, basically.
That company I wanted that company still around is by display still around. Oh, I use them just like two years ago. I think they're still around. Yeah. Yeah. Oh, the website's way different now though. Oh, that's cool.
Their website was not the best in my opinion was a little difficult to navigate. Yeah.
Apparently I saw a lot of bigger like TFT Sol displays now.
One of they still got those really cool like 16 by two character displays that were
FPC style 16 by two characters plays Yes, please.
Those are cool.
Yeah, okay, I like those a lot.
Because you can just attach those to your board with some like double sided sticky foam. Oh, that's cool.
I got to put that in the, in the show notes. So I've got a cool example here of me brute forcing a situation like this coin cell battery thing. So on on a project I'm working on right now I'm actually using 24 millimeter pots like the good old fashioned Alpha big pots, and I ended up making a footprint where the pots is there. They're what is it solder pad type, but I but I made a through hole footprint for them, where the actual body of the pot fits inside of a board. And you can solder to the body of it such that you can ground out the body of the pot and just do 24 millimeter pots on a regular PCB. And mainly the reason I did that is because these are readily available these you can find these pots anywhere. And every value every taper blah, blah, blah. Whereas like, honest to God, PCB mount ones are much harder to get much harder. And they typically like go out of stock like right when you need them. Yep, yep, yep. So instead of instead of like trying to source the right pots, I just made a custom footprint that solves all the problems. So it kind of does that, like the actual the pot is embedded in the board itself, it's like halfway the body's halfway embedded into it. It's also nice to because it adds a ton of rigidity to the to the board and like I said, I am able to connect the body of the pot to my chassis ground. So I can actually ground out things and hopefully that adds to lower noise
so I kind of like this, the the
routing of parts and like sinking them into a board to make lower profile. That's pretty cool that there's like a production part that is intended to be that way.
I've actually never used any parts that are like sides, like making a character display kind of do it. But um, I guess design considerations if you're using parts like that, because like I'm looking at the Keystone one and they've got like a recommended like cut out
for the board. So that's part could sink into it. And when you look at it, it's got a lot of a lot of play in it. Like the tolerance is pretty wide.
So I guess what you'd have to do is basically look at your PCB manufacturer. You got to actually you as a electrical engineer, you're actually going to have to do mechanical engineering for tolerances that make your opening big enough.
Oh, we I've never met electrical engineer that doesn't
Have to do mechanical stuff? Well, that's true, but most, most board designers, they just select like, you know, five mil, five mil, five mil traces, and then that handles the tolerances, you don't actually have to go and calculate tolerances.
Right? For like physical tolerances, right, you might have to do logical tolerances, but physical tolerances, like you don't have to really worry about, but in this case, you are gonna have to worry about because you have to look at the part, like diagram, know what its tolerances are. And then you have to go find your board house, what its tolerances are on Route outs, basically cut outs in your board, and then merge those two together to make sure you don't have any problems. Yeah.
And then I was trying to think of like a possibly assembly issues, I don't think,
I guess maybe if your PCB needed like to be on a carrier,
there could be problems like you need a deeper, like you'd need a cut out on your carrier for it.
This is available on tape and reel, which is nice. Oh, so you can pick places you can pick and place it. But it's pretty big. What is it? It is 33 millimeters from end to end? It's an inch and a quarter or something like that. 1.3 inches? So yeah, it's big. So your your CM would have to have a real big enough or a feeder slot big enough to be able to handle that. Yeah, like a 40 millimeter reel or whatever.
Oh, assembly issue. So you have to put it on like let's just say like, on your in your reflow It can't go on your chain bed. It's got to go on your rails. Oh, right. Yeah, yeah. Yeah. Cuz it extends beneath the board right? Beneath, right. And so
depending on how big and heavy your board is, that might be a problem. Usually, if you have like a really heavy board, that's only one sided. You just run it on the the free float. It's got like a conveyor belt in there. Oh, yeah. Just run it on that. And you don't have to worry about it. But if you have one of these parts and your boards heavy, you're gonna have to get a carrier. For sure. Right? Or, or if you're, you know, your board has rails. It rides on the pin chain. Yeah, yeah. Well, if it's heavy, you can't do that. Because Oh, boy. Oh, right. Right, right. Yeah. Yeah.
I'm lucky because almost all of our PCBs have a fixed y.
dimension. And so like, we
your racks and stuff. Yeah, yeah. Yeah. So we've rarely even have to move the rails on our oven, because it's almost always fixed. Like, we only have to have them when we're dealing with like, customer stuff. Yeah. I mean, I'm Acrab. What we do is I, I basically designed a, a,
a carrier, right, that has a sliding bar. So we never have to adjust our oven. Because this carrier is like, you know, 17 inches wide or whatever. And it fits any panel that you put, right. It has like alignment pins to holes in the rails on. Yeah, handles, right. Yeah. You know, another thing about this part that I'm looking at now.
So the majority, not the majority, virtually 100% of the mechanical rigidity of this is the solder joint to the pads, which looks fairly substantial. I mean, they're, they're, they're kind of chunky pieces. So you know, I think it would be able to withstand a little bit of force on it. But I'm almost wondering if you since you've already routed out a board, wouldn't it be nice if it had like interlocking fingers that would like clip it down in to although come to think about it, it wouldn't be picking place then you wouldn't like cut? Yeah, because the pick and place typically doesn't actually exert a significant significant amount of downforce, he usually just like gracefully places it and puts parts in place. It depends. I mean, you can but I don't think that's very typical. So it would be nice if this part could like almost like not almost but if it had like fingers that would snap into the snap hold it in place that would be better than relying 100% on your pads for rigidity. While I was actually thinking on a different note is it only has two tabs and they're all like far ends I want to know like how much vibration Can that take? Huh? Yeah, I mean, they can add extra pads that are not connected to anything for just like you know on on every cardinal direction that direction yeah
that's what I was thinking I will someone should someone should do a vibration test for that part and see how long it will last for well and something also to consider like at your CM most Ian's don't don't
do this, but I've certainly seen them before, where, you know, you have a bin of assemblies that are coming off of the pick and place or even getting transferred to an operator or something where they've rested the boards up against each other. Now you shouldn't do that they should be supported somehow. Or they should be in anti static bags, or bubble bags or something of that sort. But I've certainly seen it before where it's just components on components. And if this is the, you know, your largest component on the bottom side of your board, and you stack your boards incorrectly, then it could put a significant amount of force on this part. And in turn its pads right.
And this is just a additional thing to think about, because it's a coin cell holder, is, if you have like testing or anything like that, that requires putting the coin cell in,
you shouldn't be putting, let's say, you're part of your assemblies, putting a coin cell in it, it needs to be going into something that's not conductive, afterwards.
What I'm getting at with that is because usually a CM will bag it will put it into an ESD bag. Well, that ESD bag is conductive on the inside, and will draw off your battery.
I've definitely had, you know, batteries failed tests, because they were stored in ESD bags, like on the PCB. And it doesn't take much too, like you're trying to measure if a battery's at like fully charged versus like 90 or 80%.
so that's one thing to think about, basically, like the process of your product, like if your car is doing like the full box build, you don't have to worry about it, right? Because it's never gonna go in ESD bag. But if you're, if your CME is going, Hey, we're gonna install these coin cells to test it, and then we're boxing it up to Sunday, like, somewhere else for assembly or whatever, they're gonna put it in the ESD bags, and that's going to drain those batteries. So
either pump out, pop the battery out or figuring out something in your test fixture to apply that voltage there and not be a battery. Right? Yeah, yeah, it's kind of got you. The the the, the engineers on site, they're, they're starting to sweat because it's like, do I put something non conductive on the board before putting it in the bag? And then it's like, oh, ESD problems, because that's usually like styrofoam or something of that sort? Yes. So you're like completely defeating the purpose? Yeah.
Oh, man, one thing I saw was,
oh, man, it was a board. It had a battery on it. And then it had a header that was connected, one was connected, the ground one was to 3.3 volts, or like three volts, I think it's just three volt rail.
And it was known as a 3.3 volt rail anyways. But there was a,
a chip on there doing the battery monitoring for like the lithium battery, like it had a queen cell. And I think it was an RTC chip. Actually, they had a built in battery backup, slight circuit built in.
it would be leakage. So if there was no power, that chip would have leakage onto the rail, that's kind of normal through like ESD internal diodes and stuff. So it had some leakage there.
Typically not really a big problem, because your boards just sitting there, but
it had pin headers. And usually,
when you ship boards, you have to put a little piece of foam on the headers, or the headers will break through the bags and
basically cause damage, and then you can get ESD through the bag.
Well, that foam is also conductive. But it's usually actually even even more of a problem because it's like directly contacting the terminals at this point. Right. Right. And
I think that drained like almost every single battery in that. No.
Yeah, it's just weird stuff that you start after you've been building stuff for like nine years, like from hundreds, maybe even 1000 Plus at this point customers like and you just start to see weird edge cases like that. Oh, yeah, yeah, yeah. So basically, if it's going if you have to long term store have a a board that has gotten like ESD or get on foam or something. Take those batteries out. Yeah. Or figure out a way that it gets shipped as an assembly. Yeah, shipped as assembly. Yep.
But it's probably easiest to just not do the battery thing. You
Yeah, yeah. So basically, the best thing is during testing, if you need a test if like,
the voltage comes through on like your battery backup, have your fixture apply power there instead of putting the battery and that's usually the fastest option and doesn't have this problem. So you want it you want to make your CRM even happier. Make it such that there's like a test connector that they plug in. That applies to power and things. So you don't have to like clip into battery leads or anything like like, make a dedicated. This is the test. Connection header. Yeah. Oh, just pogo pins that your thing hooked up to? Yeah, yeah. Something like that. Something of that short. Yeah. Yeah. Yeah. If you don't want to populate a header or some kind of connector, then yes. Yeah.
Okay, any other cool parts?
I don't think so. This week's even know. I mean, I've seen I've been looking at parts all week long, but I'm sure I have some. But let's just move on. Okay. So I found I found it an interesting question on the electrical engineering subreddit, that just asked, How do I branch into electrical engineering? And what's what's fun about this or interesting is that the the person asking about this was a computer engineer, but wants to become more of like a traditional double E. So sort of jack of all trades in that sense, in terms of like, the, the electronics side of engineering, but
then they I've, I'd love to kind of talk about what that what that actually looks like. Because one of the things that this person was mentioning was, is, is it worthwhile to get a bunch of certifications in electrical engineering? And that they got me thinking like, what, what kind of certifications are there even for electrical engineering? And I'm sure there's plenty, but I'm not incredibly aware of a lot of them. And certifications in general, sort of, to me scream like big business, like many, many 1000s of people working for a company. And traditionally, I've worked for smaller businesses where certifications are less, I don't know, required, or even known about. So I'm curious if you know of any W E certifications.
Like, most certifications, I think about are not even really things that individuals get companies get certified like, right ISO and that kind of stuff.
And when you say certifications, what my mind jumps to is like it,
IT certifications and that kind of stuff. And so Steven has his link here from
i zippia, or whatever.
Zippy I so I went, I went to Google have just typed in electrical engineering certifications, just to see what Oh, is out there. It's also behind a subscription wall. Yeah, sorry about that. I the first time I clicked on it, and let me go to it. And then the second time, it's like, well, you need to pay or whatever. But But regardless, this this list of certifications, it's like top 12 Best electrical engineering certifications. I started looking through it. And almost all of them are not directly electrical engineering related or even. Yeah, they're not even related to electrical engineering at all. And most of them are.
It's for like tools, like getting certified for AutoCAD. Yeah. And I'm like, sure you can get certified to use your EDA tool, I guess.
Why? Maybe it's a question for that. Yeah.
I guess if you were job hunting,
those look good. For what was it? The HR pit of doom?
Yes, I think it's what we called it. It's very good to get past that. For sure.
That, uh, yeah, guaranteed, that helps. Because you can say I have the certifications, which means I have it's like, it's like when you go to college, and you have that piece of paper that says, I graduated four years with a BS that bla bla bla bla
it's the same thing, right? It's a piece of paper that says, I took this class and they say, I know this stuff now. So it helps definitely for job searching. I would say if you're at your job, it's not really worth too much. Unless like, it's actually you're talking about a really big company that might have
pay increases just written down for like it for the certain sort of like, if someone has this certification, they get this much amount of money. Right. I know those kinds of organizations do exist.
never had to work for one, thankfully. But those do exist. So I'd that's definitely where it'd be from, I would say as
I just can't think of,
because I just IEEE have any certifications for people to take, you know, I know so little about IEEE that I wouldn't be able to answer that. Okay, so IPC is the one I think that is probably the
the most related to electrical engineering, although there's a hardware for sure, in terms of hardware, but I think IPC hits home for you and I the most just because we deal with style stuff, right? Manufacturing of electronic assemblies. IPC, do you think that would be useful? If you're just doing board layout? That's, in my opinion, really important to Yeah, it does allow you to think more about the manufacturing process? Because that's what it is.
DJ in chat mentioned, you have the PE, professional engineering stuff, which is yes, that is a certification by your state, United States state.
I think other countries have similar things.
It's very interesting to think about at P e is is a, professional engineering is like state by state,
which is a very interesting thing. I don't think people really know that.
You know, you know, I've talked about PE just a little bit on the podcast, neither one of us are our P's. And did you even take your Fe exam, I did not yet know myself as well. And I've never even worked at a business that I could even pursue my PE, because you have to train under a PE. So I think,
at least in Texas, you have to train under one, which is like, Hey, how did the first one ever get trained in?
And then number two or two? You have to have?
I want to say it's four years of engineering notebooks, and you had to submit them to a committee.
I thought it was both in Texas. No, uh, you know, you don't have to do both. I was always told that ACM PE stamps off on you if
if you train under one, yeah, it's really wrong, though. I'm pretty sure that it's two separate things. Yeah, I think it'd be fun to look at. But
from what I've always been told that, it's that you have to do both. Basically, you have to keep your journal, effectively. And you have to train under a PE for four years, and then take your PE exam, which
is kind of brutal, but
I'm pretty sure it's an slosh, or
what state has the easiest?
I'm not sure. I've never really looked into it, because I spoke to some people in college. And
I was just basically said, like, it's really not worth it for a doubly, unless you, you know, it's worth it. Like if you know you need it, you need it. If not, like is it really worth the eight hour exam of an FE? And I suppose, you know, I don't want to discourage people from taking your Fe exam, which is the fundamentals of engineering kind of thing. And in fact, at the end of college is probably the absolute best time to take it. Yeah. Or like during college, like maybe your senior year. Right. Go? Actually, I
if I recall, at UT University, Texas, there was a class that you could take that was like, basically studying to take the FE Yeah.
The fundamentals are the fundamentals of engineering. Yeah, at a&m, almost everyone I know took their F e exam, after they had already graduated. But like, it was like finals week. And then it was a week and a half later, or something like that. They went and took the FE. So it was like right after college. Yeah. And I talked to some people about it was like, Is this a good idea for me to go and do and, you know, looking back, it's one of those things where it's like, I could have probably spent the, I don't know 100 or $200. It was to get it and just take the exam, and then you're just done with it. And then you can go and do it if you want. But I've never had a situation where I needed it. And every professional professional engineer, I don't mean an actual PE every engineer that is a professional I've talked to who doesn't have it, they're like it's never hindered me. So I don't know it but it feels like that's another one of those things where it's like, a really big business is the kind of place where they could afford to say like, we must have this Yeah,
This is in line with the,
with the whole idea of finding, like go live in the state where it's like the easiest to get a PE
is I wonder if there are companies out there that are like PE farms?
Oh, like you go work there for four years and you get a PE.
Yeah, big companies, right? Yeah, but no like that's like, there. I'm looking at it as like. So Steven and I were both in the boy scouts.
And I'm an Eagle Scout. But there's deaf. I don't know if Steven is or not.
Yeah, no, I'm an eagle. Are you an eagle too? Okay. Yeah, I think we've had that discussion before, but I just can't remember anyways. But there was definitely
like Scout troops out there that were Eagle farms. Yep. Like every single person that went through it that made it through the, you know, seven, eight years of Boy Scouts. Got an Eagle Scout like or was what became Eagle like they were farms. Right? Whereas, like, in my scout troop, I was like, the only person that got Eagle for like, two three years. Yep. Yep. It was, it was rare in mind to I was actually aware of a Boy Scout troop in my community, where they had a rule that if you were signing up, you actually signed a document saying, I'm going to get Eagle. If they were they were a farm, but like, they could pull that out and be like, this was your intent. Why are you not getting equal kind of thing? Which I think yeah, really crappy?
Boy Scouts, I think it's up to the I think it's up to the kid to go and get it. Yeah, for sure. I think that's the entire point. Yeah, exactly. Exactly. But there's trust me, I saw a bunch of other troops who are like, very much parents getting Eagle for their kid, ya know, for sure. They're Eagle farms. Yeah.
So that's, that's why I brought up because I immediately thought of that. I'm like, Huh, I wonder there's PE farm companies were like, go work.
You go work for a, I bet you it's probably more common in like civil engineering where you like almost everyone, if you're going to be a good civil engineer, you need to get a stamp that that you guys stamped.
I think that's probably more important than industry. So that's, it's probably like, if you're a new civil engineer, you go work for a company and you're like, under a PE, and there's like a program to get you a PE eventually told me that foreign might not be the right term for that. But it reminded me of the Eagle Scout thing. Well, and you know, the thing about that, that's nice. Like, you can probably expect at least four years out of that employee. If they if they do that. Right. Yeah. So it's a good hand. That's good retention. interesting to think about, because then you don't have to worry about like, is this person going to be around? You know, and so can I sync a lot training to them? That kind of stuff? Right, right, exactly. That's interesting. They might hold that for years, they'll get the stamp. But yeah, but that's a very interesting dynamic. I didn't even think about Yeah, yeah, I'm sure that's unintentional. But, but at the same time, like, I wouldn't be surprised if companies rely on that. being like, hey, we'll invest in you. But we're expecting four years. So yeah, at least.
Well, they don't have to say that part. Because they just know that they have to stick around and they're gonna be successful in that industry. Right? Even even if you hate that job, like you might stick it out for four years to get the Yeah, the PE. Yep.
Interesting. So how do you branch into electrical engineering? Yeah, back to back to the reject to the actual original question here. Yeah, what is what is the method of branching into electrical engineering?
Certifications? Is not it? I don't think yeah, certifications is not it.
just started building electronic like if it depending on if it's actually hardware, like, start building electronics, like, especially if this person has a computer engineering background, like Arduino? Yes, our plugins of LEDs are not a huge stretch to jump between those two. There. So like, Jason, Yeah, cuz because you already know how to code at that point, should be able to code and
code on Arduino, the blinking LED, like, do that. Maybe play with some shields, like, get a motor controller shield or whatever stuff like that something inexpensive stuff to do, and then build your own custom shield for it. That would be like the first step. Yeah.
And I think also the person asking this question, was interested in getting their master's in doubly when they have their undergrad. There
Bachelors in C. And so at that point, at that point completely different kind of territory well, sort of yet. So at that point, like there's a lot of overlap between E and C E. In fact, it's it, there's so much overlap that, yeah, at my college, they started calling the whole program.
What electrical and computer engineering, like they just mash them together that you'd see is actually my degrees E, C, E, E, right? So well, and so what I would do is go look at where that overlap is, look at what classes are different and which classes would be necessary to get your Bachelor's in E, and then figure out what like, is that even reasonable, maybe it's only like two classes, and that gets you you're doubly
I'd be willing to pay for a semester. If like, that's all it took to be, then be able to go and get your Masters.
I like and chat here. Mobius says, Pick a project, think about how you do it as a CEE and then do it in discrete logic.
That's the honestly, that's really challenging half the time. Yeah, depends on how, how big of a project it is. Well, if you're used to C, E, and you're used to being able to do virtually anything you want, and then you have to jump over and do it in digital logic or analog. Like your your boundaries of capabilities shrink. Incredibly. So like actually, that's a such a good exercise, because
having unlimited resources of a computer, Ivan saying Unlimited, virtually unlimited, versus like, having to worry about every single part, doing a thing is a really great exercise. And it's even fun to go beyond that. Because the next level is saying like, okay, cool. Can you accomplish that? And then can you accomplish that at a price point? Can you do that? For under $10? Or something? I don't know. Give yourself some time. Yeah. Now you're talking hardware cap one?
Well, you're talking doubly design and manufacturing at that point. There's a lot of other versions of doubly that next Okay, so that brings up another thing, Parker and I usually had to take the perspective of we're making hardware either for you or for ourselves. And so we speak to that a lot. But double E's do a ton more than that, you know, you have power, you have communications, you have semiconductor physics, you have all these other branches of Yeah, actually, one thing is like a C II would probably be really good at doing DSP work. Yeah. Especially the programming side DSP, even though it's like now you're talking about custom hardware in terms of like a,
like, for example, like a C 6000, DSP, microcontroller, right for from TI, just an example. But like,
because that kind of hardware doesn't exist inside of a computer at all, like a normal computer.
So, learning a new piece of hardware that you're going to write firmware for, to do high basic, high speed communication, basic as you would hold doing, like your whole RAM structure and stuff is all weird and fun, right?
That that might be the way to go to is like, Hey,
do get in like radio, and stuff like that, or high speed transmission communication, because then you start dealing with these fees, which are much closer to a C E skill set. Yeah, for example, you know, even programming PLCs, that's, it's different, but still adjacent, you're still telling a box to do certain things when triggers happen. So that's, that's something to consider, at the same time, get like an FPGA development board and start toying around with that a lot. I can tell you from just random job searches around Colorado like 90%. And I don't know that number, but it feels that way. Like there's a lot of high tech like military and medical out here. And there's so many jobs where it's like FPGA designer in the title.
There's just a lot of that. So you know, if that interest you if you want to do the high tech stuff, start looking at high speed FPGAs and all that jazz.
Really depends on what sector of electrical engineering you want to do. Yeah, but I think you're right, like pick some projects. Do those and that will tell you it'll you'll at least teach yourself Do I like what I do kind of stuff? Yeah, yeah. Yeah.
I think that's a when you're in school for electrical engineering. When you get to like your end of sophomore beginning of junior year. That's when you start taking these weird classes that are trying to like, break your brain open in terms of like theory, but it's trying to do
Looking back on it, it's a good thing because you start to find stuff that you're good at and stuff you're not good at. And you start to gravitate towards those things you're good at. And you're like, end of junior year and then your senior year, like, I was really good at embedded, so I went to embedded stuff. And then I was good at DSP. So I did DSP. Whereas like, I was not good at solid state design. So I did not do that I was not very good filters, did not do filters.
But if you figured all that out, kind of like
really halfway through your, your college, right? So hopefully figure out what you're actually at least it's so weird to think because most all other engineering is much more focused and, and scope.
Whereas logical Engineering News like,
hey, I want to say hundreds of different kinds of
logical engineers out there are different.
That's great word for it. Area study. disciplines. Discipline. That's, that's the better word for it disciplines. Yeah.
It's very interesting. Lots of engineers very interesting.
So, yeah, that's midway through is when you try to figure out what, or
you start to figure out what discipline you're going to be good at? Well, you're kind of forced to because the college typically is like, Okay, you have to start picking classes towards the thing. Yeah, yeah. Yeah, cuz because you start out everyone takes like, the fundamental stuff, right? Like the freshman all AV freshman is taking like the same electrical engineering classes. Sophomore, first beginning of sophomore year, it's kind of the same thing. It's like a recap. Make sure you retained everything over your first summer, right?
And then you start jumping into the big meaty, you know, theory topics. And that's when you're like, Okay, I don't get any of this stuff. I get this stuff. And so you start gravitating towards that. Right. So
at least that was just my experience.
And if you're good at all of it, great. That's awesome.
You got anything else to add to? How do I branch into electrical engineering?
I mean, probably, but also No.
Next topic. This is also a Reddit question, but on Ask electronics. And I thought it was it's a perfect topic for this this podcast. Is there a MacGyver way to measure voltage without a multimeter? And I'm like, Ah, I love this question a lot.
this is how I would do it is, the first thing you do is you have to figure out if whatever it is dangerous to you.
That's the always the first thing, right? Well, how do you do that? Just touch it and say out?
No, no, because that's what happens in Jurassic Park. Right? The kids like climbing the electrical fence and it goes off and freaking, like flies off of it.
how much of an air gap will spark across? Oh, now you're talking about serious voltage? No, no, you just take the two wires and then bring them really close together? And because you can do that when then measure the Holden installation, right? Yeah. So you don't actually have to expose yourself to the high voltage. And if it basically the only spark at like, right when they get really close together? Probably not to worry about it. Okay. Yeah. Yeah. Because because the dielectric strength of air is about 3000 volts per millimeter.
So you like to measure the if it's a millimeter and arcs? It's about 3k. Oh, this is not a good plan.
Yeah, well, I mean, that depends on a lot of different things.
Spark is then
what color the spark is. That it vaporize the wire? Yeah, well, okay. So if it's dusty, or if it's humid, that changes things. Does this change it? Yeah. So that's not a real actually a really good metric method then. Well, okay, so the Slack channel is just saying Likud and depending on how bad that's your voltage check
No, no, I like your idea. I like the arcing thing is actually a really a it's good. It technically everything arcs, right like it does. It does. I mean, that's how you're basically that square your high impedance is going to happen is that's where all your voltage potential is going to want to jump across.
That's what I'm saying is how strong
wrong. It is which is subjective, of course,
that arc would be, you can be fairly,
don't do not take my advice, fairly confident, at least I would be
or just knowing where the wires are coming from because like, if you're in a house, you definitely know they're going to be 120 or 240 volt and it's not gonna be any fun for anyone to touch. Yeah
I'm not a big fan of leaking batteries. Like, for some reason, everyone in chat is like, look the battery or look the wires. Like no, that's the worst idea ever, I would say.
Okay, so I've got a thought on this and here's his, so we're gonna we're gonna totally MacGyver this like, assuming MacGyver is like, okay, we're available. So MacGyver actually has to go measure voltage, then. Yeah, yeah. So he's actually find the voltage of something without a multimeter or, or measuring equipment. But let's, let's assume just for this, this question that MacGyver is an electrical engineer and went to electrical engineering school. So that what that will give the MacGyver is the electrostatic force equation, which is K times Q one times q 10 divided by d squared.
So I think the best situation would be to make an electrode scope, which basically, if we can assume that there is a paperclip and like fishing line available, then you can ground out the paperclip to attempt your best like, bury it in the ground for a little bit and make sure it's at zero volt potential as much as possible, and then suspend the paperclip by that fishing line. Oh, measure how far is pipe? Sure. Yeah, yes. MacGyver. Always MacGyver is in like a warehouse. It's always like pipes and stuff. So you use ground to that. Right, right. And then and then measure the deflection of the paperclip and calculate the force based off of that, and you can get basically the charge difference between them, and then you could back calculate voltage.
Oh, I like that. Yeah, I think that's and basically that's a like, maybe you've seen it before. Now. I think the most optimal situation is to have a vacuum bolt in a chamber. And but like the gold leaf thing, where you apply charge to it and to gold leaf plates repel each other. Repel? Yeah, I think that's sort of like an original voltmeter in a way. Yeah.
Going off your your first idea is, you could make an electromagnet.
Right, and then figure out how much weight it can pulled?
I feel like I mean, yes, absolutely. That would be that might be.
That might be easier to do then measuring deflection or something. Depending on what tools you are, what items you have.
Can we measure voltage with bubblegum?
If usually bubblegum to hold the string up, if you had Wait, wait, wait, if you had a known, like length of wire and you knew its resistance, could you not attach it to your random voltage? And somehow calculate the current through it based off of how much temperature rises?
How long it Wait, if you had a known amount of water?
Could you not put that in the water and then calculate or time how long it takes that water to boil? And then back calculate how much energy does that work? Or just temperature rise? Yeah, sure. Yeah, just temperature rise. That'd be a way to do it. That'd be a way to and now we're adding a whole bunch of like extra variables into well, no, that's how we always did things in the show, though. Right? Right. So yeah, if you knew if you knew the mass of water you had and you're the total amount of water, and you didn't know your voltage, but you knew the resistance of your wire, you could calculate how long it took to raise a particular amount of water by however much. So you could find out how much energy you put into the wire, and then you could back calculate the voltage that was applied to it. That's making the assumption that that voltage doesn't change. But But yeah, if you had like a constant voltage source, or your mystery voltage, I think the problem with a lot of these ideas, is we're assuming you don't have a multimeter but you have other ways to precisely
right. Well, but but that is the I guess the the legislation thing is probably the easiest easiest, because you can probably actually get away with, with like a tape measure.
And that will get you kind of close I would I actually, I think you could probably I just guessing here, but you could probably like even just make your own measurement stick and make like three, four or five triangles or using geometry, you could create like your own Protractor effectively that this thing would go through. And then you could measure angles based off of that, using whatever units you want, that you've created, and then you back calculate voltage based off of that.
Hmm, yeah. But yeah, I mean, we're just talking about you know, you're on a desert island and you need to calculate voltage and voltage, but you need a very precise like the radio you need to turn on the talk like Gilligan is there with his coconut radio, but it needs a precisely calibrated coconut. Yeah, but precisely, he's calculated out that he needs 18.93 volts. Yep. So you have to make sure he's at that voltage. Yeah. And MacGyver is like, I can do it. I got this. Got it's.
Yeah. You got a paperclip and a bubble gum wrapper? And yeah, there you go. You just measure the deflection between the two? Yeah. And that might be the easy, especially given with not a lot of precise ways of measuring that might be the best way. I think Electromatic would work to
that could possibly work.
Well, that depends on extreme. I need a lot of back that wire to make that work. But I guess it just depends what you have on hand.
Yeah, if you had
if you had a coil,
say, Okay, so let's think about this. If you had a voltage just
somewhere, I don't know it like it's on a thing. Like a fork, we have something. This voltage doesn't drop at all. Well, what I'm wondering is, okay, so if you have a static voltage, then there's a static E field, right? And if you had a coil in there, you could move the coil and induce a current in the coil. Could you somehow back calculate based off of that? I mean, the answer is probably yes. But now we're starting to get it. Yeah, but how accurately Can you do that? Not really. Yeah. Not very well. I think the trick is, how close what's the best method to get a
close enough or an accurate enough
measurement? Okay, wait, wait, wait, I remember actually in college, there was a way I wasn't part of this team. But there was a team that made a radio based off of a rusty razor blade
a coat hanger and like an ear for crystal radio. Yeah, effectively they use the razor blade as a diode so if you if you were okay with having your
you measuring in quantized diode section so let's say point seven volts I doubt a rusty razor blade is point seven, but let's just pretend like it is. If you could stack those rusty razor blades on them, then you could be accurate to within one. Rusty blade drop, right? Yeah, no, that's, that's good. Yeah, yeah.
I wonder what is the voltage drop across a rusty razor blade? And what what was it rubbed on? Was it graphite? I don't remember trying to remember how I think that's correct.
I do like I'm starting to look at some of the answers on here by like a co workers fingers.
That's pretty similar to the Slack channel. Just saying Likud? Yeah. Yeah.
I would think the problem with the diode thing is, you know, if it's a lot of voltage, you are
gonna immediately blow it. Yeah, I guess that's the whole point. You don't know what the voltage is. So it could be lethal. It could be nothing. Yeah, so I think doing an arc test is your first step. Right? Yeah, that's good. That's good. Yeah, it because if it arcs over anything, like visible distance, you know, it's a ton of voltage. Yeah, yeah. Whereas like, You got to pretty much virtually touch them. And depending on how energetic that is to
might be something you want to mess around with or not.
Yeah, I could totally see a MacGyver thing where there's a
And like an energized coconut that you put your hand on the coconut your hair stands up, you know
I want to try it. I'm kind of want to try this, like, how close using your deflection method? How close can you get?
Like I accuracy wise? So I think some of the I don't even remember what they Well, they were called electro of scopes back in the day, but but some of the first ways that humanity measured voltage was using a deflection mat. Yeah. So if you have very known, you know, plates effectively, that are suspended, and one of the reasons why they didn't vacuum is to remove any kind of extra interference, you could calculate it right?
Well, so so if you have to calibrate the deflector, is that really something you can MacGyver in a warehouse?
Maybe we get a little too much in the weeds on this, I think we are getting into the weeds on it. But will it matter?
Well, one thing I guess we could do is
one thing to research is how do how do we know with really high accuracy? The
the charge of an electron? Because if how, like how do we know today? To whatever decimal place we know that charge of an electron? How can we convert that to something that is easily done on a desert island with paper clips and fishing line?
No, no, that's a good point. That is good way to think about it, too. Yeah. Yeah. Because then that that gives you the fundamental towards whatever you're trying to get to.
There's got to be some really elegant way of doing it and being super accurate, you know? Yeah, I'm thinking like, at best, you have like a tape measure. Right? Or like, maybe not even that maybe using just like, your body parts, like knowing like, the middle part of your knuckle is around an inch and like your forearm from like, your wrist to your elbow is about a foot, stuff like that. That's like really rough.
How close could you get? And I bet you there's like metric equivalents to that too, right? Like a female is like a metric fleurs maybe?
So I'm metric knuckle, sorry.
I like that. That's a cool question to ask. How would you go about that? That, you know, that would actually be a really fun question to ask at a at a college, just go to a find a find a classroom and ask ask a bunch of students that and have them just try to brutalize it. I wouldn't ask that on the next. My next interview, I interviewed an engineer.
I'm not saying that.
I read that he was like, Yeah, well, maybe not now. Yeah.
We'll say we'll say this next topic for next week. Yeah, maybe, you know, I'd love to maybe, maybe it'd be some discussion in the Slack channel. Actually, this would be really fun for the whole Slack channel to come together and say, like, how would we build a voltage detector? Yeah, no measurements? Like how close can you? Well, yeah. How close can you get using? Just what's, you know, the clothes on your back? And maybe a tape measure? Because it has to have chewing gum in it? Somewhere? Yeah. Yeah, because MacGyver always did that. See the problem with the deflection is that I don't think like a tape measure probably isn't sensitive enough. Or it's sensitive enough to you to be able to detect deflection. But I don't know the force is required to move them apart far enough. Like what what kind of resolution would you be looking at? If you have like a tape measure that shows 16th of an inch? Right? Well, it was like, we were talking about my first idea, which was just used an arc. But it's like, you're like 3000 volts is a millimeter. And I'm like, that's your resolution?
Yeah, cuz it's, like, from 50 volts. DC 50 volts down. generally safe is you have dry fingers, generally safe. Yeah. So you have 3002 50 volts of like, unknown region. That's why I love the arc idea. But the problem is like, by the time you can even get to the point where you can visualize it with your eye. You're like, you want to be far away. Like yeah, yeah.
What is it, Ken? Oh, well, so if you could figure out a, you could use the ark, if you could. The problem with the Ark is, I don't think you could accurately measure the ark with simple tools, like you would need, like a micrometer to measure that arc, right? Because what you could do is take the two pieces of wire, slowly bring them together controlled, right? And then the moment you detect current,
so you can have like a light bulb, right? And series, the moment the light bulb starts to do anything. I mean, we're assuming that it will, it will emit photons that you can tacked at any current you can do would probably be make the end and make that measurement of distance. And then you would know your voltage. Yeah, you'd have to define what an arc means. Yeah, actually, that's a good point. I don't know. To me, it's like when it photons off into your eyeballs. Right. Right. Right. When you can see it. See it? But is it like a?
Or is it like leakage current above or certain? Because it's probably not? I'm gonna bet you're in arc is not instantaneous. It probably has a ramp. Yeah. Yeah. Like
when you get really close yet, like electrons are being stripped across, pulled them off. Yeah.
And when that the kind of distances we're talking about, it's probably incredibly minor. What's actually happening right? At that point, you'd have to have precision stuff just to find it. Yeah.
It definitely would tell you how dangerous it would be, depending on how energetic it was. But that's about it. I think.
This race wait to me this question will raise more questions. And we answered.
Well, that's how it goes on the macro fab engineering podcast, where your host, Parker, Dolman and Steven Gregg, later one
I have I have one other way, okay. If you have a bucket of water, right, and, and you pour the water in a laminar flow, assuming you can get laminar flow adjacent to the voltage source, it will curve the water, it will actually attract the water. And then if you do it from a high enough source, you could measure how far the curved water was on just the sand or the ground or whatever. And that would allow you the resolution because if you go higher up, you could see where it falls on the ground and then back calculate that. That might be the best way to do it. Yeah. Because then because then your scale is kind of arbitrary.
If you like let's assume that you could move the voltage source up like 10 feet up how much the water would curve over that could
or you could move down and get closer Yeah, that might be the best way of doing
this will you say take it easy? Oh yeah, take it easy.
Thank you Yes, you are a listener for downloading and listening to our podcasts if you have a cool idea project or topic or a way to MacGyver a multimeter let Steven I know Tweet us at Mac fab at Longhorn engineer or at analog EMG or emails podcast microsoft.com and check out the Slack channel which everyone's gonna be talking about this this topic in the Slack channel. It is macro fed.com/slack Or come hang out with us every Tuesday at six o'clock pm on Twitch as twitch.tv/macro Fab
A custom, open source, DIY multimeter? Parker and Stephen go down the rabbit hole of putting down design requirements and what open source means.
Stephen and Parker continue the discussion of the voltage measurement. Can you come up with a way to measure voltage without precision tools?
Stephen gets an upgrade in his electronics lab with a new multimeter, A Fluke 87V! We break down Stephen’s old meter vs the new Fluke.