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.
This week, Riley Hall of Fictiv joins the podcast to discuss how Fictiv connects engineers and designers to job and machining shops.
The US Mint Denver produces 30 million coins a day. Denes, the tooling department manager, discusses with us how production at this scale functions.
Previous Podcast where we discussed Engineering Resumes
Interviewer Questions and Techniques?
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, dry projects, manufacturing, engineering news, Engineering News, industry news, and engineering interviews. We're your hosts, electrical engineers, Parker, Dolman.
And Steven Craig.
This is episode 322. And you would think we can get that right sometimes. So we got two topics this week, we have kind of like interviewer questions and techniques that Stephen and I use while interviewing people, for our companies that we work for. And then the other one is a little more interesting, maybe, who knows, depends on what side of the fence you are on. Or if you're looking for a job or not, I guess it's PCB rulers. And so we're gonna start with PCB rulers first, because the other topic is probably going to take like 58 minutes, and we'll forget that this other topic exists during that. So a long, long time ago, Mac fab used to make PCB keychains that were like, little basically mini rulers that we would send out to people. And our marketing team wants to do PCB rulers again, because I think it's great swag to give away as well. But I just don't want to do another PCB ruler, because I have a stack over here of like, 12 of them. And they all have like the same thing on it. Sure. Like there's a ruler, that's like the first thing you have to have a ruler on it, either metric or imperial or whatever. But they all have varying different degrees of just information on it. Like like the Digi key one is probably the most dice.
Yeah, it's dense. There's a lot of stuff on it
while stuff on it. So one thing I want to talk about is like what wouldn't make one unique enough to where people would actually want it. Besides just saying macro fab on it, it could have like a picture of you and I on it in any blocks you want that.
That would be weird, actually. So I haven't thought about a project I was going to do a long time ago when I was in the I was in an art collective in. In Houston, we made a bunch of sculptures all around Houston. I was there was four of us in there and I was going to do all of our faces in copper, just basically copper clad fr four but leaving it leave it as raw copper such that will perhaps like I was actually going to leave like I was going to draw all of our faces but leave the facial hair of all of us in Rockhopper. So it would like slowly like oxidize and change, fuzzy. So what Okay, so what would people want to see on these kinds of things? Or what would people actually utilize if they had, you know, so I had a thought earlier. And I would totally use one of these. But this is perhaps a little bit more towards the hobbyist side of things. But if I had a ruler that had holes for headers on it, that were point one pitch, like they just accepted a normal point one inch pitch header on it. And it was just a line of holes. What you could do is you could take a header, you can count how many you want. Like if you had a 40 pin header, you count how many one, put it in the hole, and then you could break it off at that point. And then you would know you have five or seven or 12 Oh, yeah, so just on the ruler have a string of holes. And you could just break it at whatever point you wanted.
Yeah, that's a good idea. Yeah.
Because normally what I do is I just get out some snips and I count them and then snip it at that point. But if it's on your keychain, you can break it right there.
Yeah. I thought about putting like a beveled edge on it. And then you can open up packages and stuff like packaging tape and stuff with it.
Yeah, like a blade.
No, just a beveled edge because like, I mean, everyone in here is like user keys like open up a box and stuff. Like you don't need a particularly sharp object. You just need a hard mostly kind of sharp objects like blunt
like a chamfer the edge of a PCB and it's sharp enough to go through some tape, I suppose. Yeah,
as I was saying just like beveled the edge of it and then it will go right through a probably a sandbox state.
Yeah, yeah, I like it. I mean, you can always go cliche with it and put The proper cutout in it. And then you have a bottle opener in the ruler as well. Oh, yeah,
there's ball openers too, huh?
Yeah, like I said, it's kind of cliche though. What what are the things good a PCB solve for you if you just carried it around and we're talking mechanically, I suppose like this. Yeah, it's not going to be something that's assembled. It's just a board by itself.
Yeah, I'm not going to put like a circuit on this because some like, people have done business cards and stuff. I've done a business card. Yeah, circuit board before. That's what I'm seeing is like, yeah, what mechanically, I thought about actually, instead of making it like a ruler, that or like a keychain, like maybe like a credit card shaped so you put it in your wallet. So you can have dimensions and then like, drill hits for like, I think the drill hits are really important because that sometimes helps out when you're trying to figure out like, basically the size of like, leads and stuff that diameter holes and stuff. But I always felt like the footprints are not super useful.
No, I first of all, yeah, sure. Like, okay, you see a SOT 23 on there, it's like, okay, great. Yeah, what am I going to do? Take us off? 23 put it on there and be like, yeah, it's a sock. 23 Right.
I think that's kind of the idea. Yeah.
So Parker and I, we've been over this a handful of times, like, I'm not gonna just look at someone else's footprint and be like, oh, yeah, that's exactly I'm gonna make my own right. So yeah.
So Fabio firmware in Twitch chat says, I have one of the small macro fab ones that keep in their wallet. I use it for holes and silkscreen text size. Awesome. See, the text size too, I think is very
useful. That's super useful. Yeah.
So silkscreen hold drills. has to have the ruler stuff on it. I'm thinking about actually making it credit card size instead. So you can put it in your wallet.
Are you are you thinking of going like, point eight millimeters?
I think you can do point eight. You can't really put a bevel on it. Yeah, probably not. Because I do want to be able to use it as like an opener.
True. Yeah. Oh, I
wonder if you could. I wonder if you can bevel inside cut. I mean, letter opener.
Yeah, you go to use you're saying like, do like a like a shape? That's like a fish hook. And the inside of the fish hook is beveled. Yeah. Yeah, I see. I see what you're going out there. Work. The CNC machines they have at PCB manufacturers could do it now. Are they willing to do that?
Yeah, they're willing to do that. If the quantities so it's like, who opens letters nowadays anyways? Yeah.
Well, okay, so actually, so the thought, okay, so beveling the side of it could work as like an edge and blade edge, right? Yeah. A very, not blade edge. But, but if you made like a hook cut out in it, and you grab inside of like, like, you put that in a cardboard edge and grab the tape and cut with that, like pull it towards you. There's something that could work. Right.
Yeah. I think that would break. I guess you could try it out, though.
Well, it would probably break out on a 0.8.
No. 1.6. So yeah.
The thing about 1.6 is that that's in your wallet. That makes your wallet really stiff.
Oh, yeah, I guess so.
Yeah, there's a lot of constraints with something simple like this, right? Yes.
Well, I'm wondering if I should do a wallet design and a actual ruler keychain design. Like and have like the have the bevel on like the keychain, but didn't do a thin one for your wallet. That's got a ruler and that kind of stuff, but just doesn't have the beveled edge and has some different information on it.
Sure. Do both. Yeah. Do both? I don't know. Yeah. There's, it's like there's not a whole lot that can be done with it. Right?
Yeah. Cuz we'll have an inch ruler and then you have metric on the other side. Of course, is there any, like weird measuring systems that we can add to it because we have technically four edges that you can put stuff on?
Yeah, but I mean, this is not going to be very long. If it's only like credit card size. So, what is the dimensions of a standard credit card?
Like three inches by inch and a half?
Yeah. Well, um, and do you want to do the the tick marks for measurements? Is that done in copper? Or is that done in silkscreen?
I would say copper we do copper this time. Yeah,
I think copper is better. Yeah.
I just don't think there's any like measuring systems that would would infuriate people if it was like included
a Smith chart on the on the backside because
some people get some people get unusually irrational when you like, say stuff in like SAE or or imperial.
Yeah, too bad. You can't, you couldn't do like a compound bevel on it and then make it a sparkplug gauge, you know, gap set gauge,
oh, gap setter? Yeah, that'd be cool. PCB feeler gauges.
Yeah. PCB feeler gauges, you get point eight millimeters one millimeter 1.6. Just all the standard sizes.
I've always wanted to do like a, a color chip to like a set of like, one inch by one inch squares that are all the different color combos. Oh, yeah, all the solder masks and all the silk screens. Like matrix together. So like, you know. So you can have like red silkscreen with yellow, green, black, blue, because it just watches. Yes, watches. I should do I should do that. Let me get that done.
It would be really cool. If you could convince a place to do all of that on a credit card size, like squared out on one. Yeah, if they would be willing, I mean, that would be a ton of work for them. But if you had, like, maybe not even all the combos, because most of the time I think white or black silkscreen would be acceptable. If you had all the mask colors, and then white and black on both. That would be really fantastic for for just pulling it out and being like, this is what PCBs can look like.
Yeah. Hmm. There are some places that do like full color PCB printing. But they kind of like it's like a post process. It's not something that's through the normal PCB process. So interesting. Well, if anyone out there has ideas for this piece to be ruler, let us know in the Slack channel or on Twitter. Because that's something I need to be working on soon ish for the marketing team. Because they're like, We need to give stuff away. And I'm like, Fine, go design this thing. So
I almost wonder, this, this is just my brain working in this is probably stupid. But if you had a thin PCB backer board, and then you got little squares of PCBs made in every solder mask color, and then use a pick and place to put those on the backer board, and send it to the oven, and actually reflow PCBs to a PCB. Woohoo, yeah. And since you have a pace jetter you can shoot paste in like a grid around all the squares, and then actually solder them to a backer board.
That's good idea.
And then, that doesn't require a ton of extra work from the PCB manufacturer.
Yeah, you just get like, half inch by half inch. Like PCBs made with capsulated edges.
Right, exactly. And then and then you you use your pick and place to put those all next to each other in a grid.
That's a good idea.
But that's a lot of work. I mean, it would be really awesome if you could get every color of a of a square of PCB on tape, and then you just load it in the I
don't think it's gonna be someone hand place. Who knows? Yeah, I'm just saying like, that would
be really cool. Yeah.
No, okay. Now on to interview questions and techniques.
So yeah, both the both Parker and I have been interviewing candidates recently, both for engineering positions. And I think Parker, you've been doing some engineering adjacent positions, right or correct. Yeah. Some positions that are heavily involved with the engineering team. So I just finished up last week around of interviewing, so I put together some some stuff for those in views and where we finished up and we made an offer to one of the candidates. So I'm happy to share some of the stuff that I've been doing here. So I kind of structured my interviews in, in kind of two sections, I start by walking through maybe three guests. So I start by having the candidate give me like a rundown of what, you know, their background, what they're currently doing, what they're into those kinds of things. And that's just like to hear them talk and to hear what they're currently doing kind of stuff. So that first section is maybe 1015 minutes, depending on what there is. I tried to pull things out of their resume, like if they say, highly skilled at soldering through hole and SMD. In their skill section of their resume. I'll be like, hey, talk to me about that. What do you mean by highly skilled? And then ask questions like, what's the smallest thing you've soldered? You know, like, and sometimes it'll be like, Oh, I've done some Oh, eight, oh, fives. And some people will be like, you know, I'm a psycho. And I do Oh, two Oh, ones, you
know? Actually, I do that, too. I'll go through the resume the resume, and I will pick out stuff that that will be like in the far flung corner that most people don't look at. And I do, because if you put it on your resume, yeah, I'm gonna ask about it. Right? Sure.
I think that's.
And even if it's a long time ago, or whatever, if it's on your resume, you should be able to back up what is on it, no matter how long ago, whatever. It's not applicable anymore, you need to remove it is my opinion on that. But like, I had someone who said that they were they had Python programming down, that they were lying. It was a they have they had changed one line of code in a Python script before. That was Python programming to them. So yeah, I guess lying is not the right term. That's harsh. But it was a misinformed, I guess,
of a maybe maybe bloated, a little bit. bloated. Yeah, that's probably more fair. Well, and you see, in that first section, what I like to do is instead of like, Oh, I see you've done this, I start and asking questions about that. What I do is I say, Hey, I see that you've done this, just talk about it. And and then I see like, you can tell really fast. If you say like, Oh, you've done Python programming. Tell me about that. As opposed to like, Oh, here's some questions about Python.
No, no, I mentioned it that way. No, you're correct. The Montt usually my first section is I kind of like want to know, like how the positions I usually interview for, which is like data support technicians and test engineers and stuff, like you don't like suddenly with your people that you're hiring, like, there's not a school to go do that stuff, right? You don't. When you're like, nine years old, you don't go I want to grow up and be a data support technician. No, that's not a thing. Okay. I think there might be one person out there that's like that. Yeah. But possibly, you can't have grand statements like that. You can't have never right, because it's always a chance. There's always a chance.
There's that one like nine year old listener who's like typing in right now.
Yeah. And I feel that person's parents should not let them listen to this podcast.
I guess we're PG 13, right.
You said nine year old though.
So anyways, I asked them, How do they get into this industry? And like, I want to know their origin story, because everyone's got a story of how they ended up like us. for better for worse. Yeah, sure. So I like knowing that about the person
Yeah, yeah. The, I think the first section is more about them just talking about themselves and like, you get a lot from from talking to people or when people you learn a lot when you get to just see how they handle talking about themselves. Some people hate talking about themselves. And, and you have to pull it out of them. Some people love talking about themselves, and it's like okay, well Need to move forward kind of stuff?
I do like, awesome blossom in chat is saying, asking what their version of highly skilled is. If they have that on their resume, that's actually good idea that fits perfect in this section, right.
You know, I in an interview I had years ago, I actually had somebody talk asked me some questions about something that I did on my skill section. And I feel like I answered it really, really well. And the guy was like, Oh, that's fantastic. Do you consider yourself an expert? In that? I was like, nope, nope. No, I do not. And he actually was like, yeah, good answer. Like, and
good. Just wasn't like to be an expert. You got to do 10,000 hours is like the minimal.
Oh, yeah. Yeah, it's something like 2000 hours just to get proficient. And 10,000 to master something like that. Yeah.
I think that's good, too. Like it did to ask like, are you an expert in something? If you're, if you're asking somebody who's fresh out of college, or 2122 years old? And they say yes to being an expert in something? Like, maybe yeah.
This really this whole first section is kind of like, personality tests? Almost. Because because that's how I view it is, you're going to be working with this person for every single day, for years, right? A decade, you know, if it works out the best, right? So like, for me, being able to get along with this person is more important than whether or not they're actually the best person for the job.
100%. And we use the word VOD at work. But no, seriously, even though I think that's a nebulous term, and it doesn't, it means something different for everyone. I think, if everyone comes out of an interview talking with someone and be like, how was that person's five? How do they vibe with us? How do they vibe with our culture? And with with our people, if every one is like, yeah, I really liked it, then. That's that's a good that word
is? Yeah, I have a question. That's usually my last question. I know we're talking about like the beginnings of in a few. But this fits in this is I always ask why did you apply to macro fab? Why macro fat. And I've gotten questions of I need more money to like they believe in the vision to they want to do more US manufacturing, like this huge array of stuff. Yeah. And I don't if someone says I need money, I don't hold that against them. I'm asked hold it. That's why we have a job. Right? If we didn't need money, like Steve and I were probably just talking to microphones for 24 hours a day.
We just do this all the time.
Just do this all the time if we didn't have to get paid.
Yeah. I mean, if anyone would like to pay us full time to do this,
that'd be awesome. That would be fun. Yeah, awesome. blossom in chat, Twitch chat money yet. I've had I've had two people say that. And it's totally fine.
You know, you know what I like about that is? That's just honest, that's just like that raw honesty.
Yep. And I really appreciate that. That's what you get out when you're trying to get through these, like, kinda obscure personality questions that Steve and I are talking about? Like, we're trying to get your vibe, right. And one of those things is, you know, honesty is a big, honestly, and is a big part of engineering. We've talked about ethics and engineering, honesty is part of that. And so trying to call that out of people is a is part of the process. I guess, the
god the last thing ever, in an engineering interview, I can't speak to other interviews. Just don't be us. Do not be us at all. If you know something, be confident and say you know it, if you don't know something, be confident and say, I don't know that. Like, I'm not gonna hold that against you. I'm really not it might not get you the position, but like, it would be far worse if you lied about it.
Yeah. You could. The people who say I don't know, and just leave it at that I kind of marked down I guess. But the people who say I don't know, but then they follow up on like, maybe how they were trying to figure it out. Without Oh, yeah, yeah, that's get those are actually I would put higher marks and if they actually knew the question it sir.
Yeah, maybe I should amend that, like just looking someone straight in the face and being like, No, I don't know that and then silence that's, that's not positive. That's not good. No, it's
not positive. It's because we're not infallible creatures either. Like we mess up all the time and how much of your day is spent looking stuff up? Yeah 80% Maybe? Oh yeah, your day. Yeah. Looking stuff up.
I was I was looking up rj 45 pin outs today because I was running Ethernet cable. And I was I spent a solid chunk of the day looking at do I need to make crossover cables? Or do I need to make regular patch cables? And is this gigabit switch I have that will automatically like, yes. In other words, a lot of it is just like looking stuff up? Because I don't know it. Yeah. Actually, you know, my boss and I were mentioned that the other day school teach you how teaches you how to be resourceful. It doesn't necessarily teach you like raw facts, and all the rubbish, it can't it teaches you how to teach you. Or it tries to
how to teach yourself. Yeah, right. What you didn't learn the pin out of USB Type B, in college.
Dude, though, we don't get anywhere in college. So, after, after I kind of do the whole personality thing. I tend to, depending on depending on the position. We'll we'll go into more like difficult, like specific on the job questions. So if this is like for a tester, or an assembler, or somebody that will probably talk about soldering, or using an oscilloscope or something like that, before an engineer, I have actually started giving a bit more of an exam. And it's not necessarily an exam where there is like, hard and fast, true answers or correct answers. It's, it's designed to be I want to see how you get a question, digest it, and then find some form of a solution. So some of these questions that I give for this exam do have like there is a right answer. Most of them have no right answer, they just have like, Let find things out. So I actually have a schematic that I drew up the other day, and I pass it on to Parker and Parker is going to put it up on the live stream here, I'll actually throw this schematic up in our Slack channel, which is Mac fab.com/slack. So if you want to kind of follow along with a little bit of these questions and take a look at this schematic, feel free to it'll be up in the Slack channel. So for all of the candidates that I've done with this mini exam here, I provide the schematic ahead of time, at least a day at a time. I think for some of the candidates it was it was probably two or three days ahead of time. And I've asked each each one to take a look at the schematic before the exam. So they're aware that there's going to be something involved in this. So first of all, just as sort of like a spoiler alert here, what I really am looking for, whenever I provide a little schematic like this, or something of this is I want, I want you to go and get an idea of what this the circuit is doing or trying to do. And I specifically put regular jelly bean parts and one or two unique parts on it a unique part being one that you haven't seen in school, one that you haven't seen before, it might be industry specific, but it's it's datasheet is very, very readily available, like you just go to Google type it in and you will find it kind of thing. So that was one of the one of the kind of goals there with with this with providing it ahead of time is are you going to go and really look the schematic over? And are you going to look at data sheets ahead of time? And for some people? Absolutely that's like a no brainer they go and they look at it for other people, they just kind of like glance at it and sure, okay, you know, that's fine. Perhaps that's enough for them. Or perhaps they already know some of the things on this. And so the very first thing I do in the in the exam is give a preface by saying this schematic is fictional it this isn't a real thing that exists. And you probably don't have all the information in fact, like I don't have any connectors like power supply connectors on this schematic or anything like that. And sometimes I even leave that information out because Sometimes the candidates are like, Hey, where's the power supply connector? Good question. It's not on there. And in reality, you may not even like when you're on the job, you may not have the schematic page that has the things like a power supply connector and things like that. So I just want to see how your mind interprets this kind of schematic. So really, the beginning of my exam is I ask the candidate to look at the schematic and tell me, what does this thing even do? Like what do you think it does? Like? You can go into whatever level of detail you feel like doing or not, but just like, overall, what is its function? And Parker's got it up here this bright? You've probably seen it now for a minute or two. I'm curious if you have any, just initial thoughts on what it does. You're talking about? Me, right? Yeah. And I'm being unfair to you, because you've
got an STM 32 microcontroller. Yeah. From that's over spy. Yep. Got programming port that talks to the C 32. Programming. We have a something called CV offset, which I don't know what that is, but it goes CV stands for actual voltage. Okay, so it goes into an op amp that's got a reference voltage, it's going to offset potentially ometer and looks like a trim pot probably for calibration.
That's actually that would be a manual control on a front panel. Okay, that would be a pot control.
And it goes into a voltage follower for apart from being buffering. Let's see output VCA voltage control amplifier. Yep. So it's a signal in goes through a couple of op amps, and then goes to output. So what is this control signal off of you two? 40.3? That's doing something.
So yeah, that's that's a, that's the special chip. That's a Yeah, that's
the thing. That's what because they look at everything else, like the input goes through a believer. Yep. Just linear buffer. Yep. And then it goes through this thing.
That's a, it's called an SSI. 2164. Yeah, I don't know what that is. Right. That's, that's the one part where if you go to Google and type in that bar, you'll get the exact thing and with a whole description of it. And so effectively,
steal this from chat, it does nothing because you can't buy STM 30 twos right now,
I was gonna mention that, too. That was great. Fabio from Yeah, Greg can't do anything because you can't buy the chip. So effectively, what this is, is it's literally a pot and a jack input that that go into an ADC on a processor, that goes to a DA C on the output of a processor and controls an amplifier. So the the the jack in the in the pot at the on the front, just control the volume. That's it. So it's just a voltage controlled amplifier that is done digitally. So nothing. So it's a decent mix of digital and an analog here. So So yeah, and so a lot of my questions that come that surround that. Some of them involve design stuff, like there's some capacitors in feedback paths of op amps, I asked, Hey, what are the function of these capacitors? What do they do? And then, you know, if somebody is like, you know, nails that question, figures it out, I'm like, Okay, can you tell me what the cutoff frequency would be? Or can you tell me what the equation of a cutoff frequency would be for a capacitor and a feedback in an op amp kind of stuff like that? And that would be more of a design style question. Now, I also have manufacturing questions where, you know, I tell them certain aspects about the circuit. And if you look at the schematic view, and you know, the schematic, and you're able to analyze it, you'd be like, well, it shouldn't be working that way. And then we'll have a discussion about like, Okay, you're right, it shouldn't, it should be working that way. Or, and what could make it not do that. So, you know, PCB issues, like broken traces, or lifted components or missing components, like things of that sort. And then there's a favorite that I like to ask where, say, say you have a device, you know, it should be pulling about 100 milliamps, you plug it into your power supply, whose current is set at 250 milliamps, and it immediately trips that constant current mode. So, there's a short what do you do? Like? How do you handle that situation? And it's really interesting to see people kind of like, range short circuits when they're trying to figure out a short circuit.
Yeah. I'm Bill, who's one of the engineers that macro fab asks is very similar question to that. Okay. And now She that was what spurred this whole. You told me about that test, basically. And that actually what spurred this whole conversation that we're talking about? Because, like, I asked a bunch of questions. My biggest problem I have is I have so many resumes go through. Yeah. And it just takes a lot of time. And I'm like, I started looking at, like, what our developers do at macro fab. And they actually have developer tests that they send out to candidates, and yada, yada. And a similar thing for hardware engineers. So I was actually going to do that same thing now is I'm going to build a couple tests for the kinds of positions that I interview for. Like for tests engineers, that's totally awesome question for test engineers. Oh, yeah. Yeah. But I was going to do I was actually going to build basically an RMA packet. For them. Yeah. And basically, like, here's the Gerber's. Here's what the customer is saying is wrong, you know, figure out what's wrong with this nice. Kind of mullum, maybe a little more open ended, because I'm gonna look at this as being a filter. Yeah, and one of those, like, you have to do this, you have to at least answer this before. Like, maybe I've been looking at stuff, right. Big One is data support technicians. And I'm actually going to make a data packet that people will have to like upload to the platform, and use like our knowledge base to figure out how the platform works.
Now, are you talking about giving this exam during the interview? Or like, is this a separate kind of thing?
So because we use like this HR platform thingy for people that can apply, we can put in a test there too. So when they apply, they have to answer the test basically. So like, for software developers, they Oh, they apply, and they get like a code challenge, basically. And they have to submit the code challenge for their resume to get through. Nice. So kind of like, it's a filter. So my goal is to, like, squish down how many resumes I have to look at to people who are, you know, because these are questions I asked on the interview anyways. Whereas, you know, like, at the percentage of people I'm interviewing, don't know how to answer the question that you just asked, which is, you know, how to solve for short, and they're like, applying for a test engineer position. Yeah, it's like, well, if you can't do that, that's like the simplest, you know, fault finding. Right? So
it can be right. Yeah, it will also can be, like I said, with, so I have about eight to 12 questions that I asked. And I most of them, I don't necessarily care that you get the exact right answer. I just want to see how you approach it. Yeah, yeah, exactly. Especially like with the short thing. There's so many ways to approach it. There's
a lot of different ways to solve that problem. Right. There's also a lot of ways
to get it wrong, like, in to just say things that are just not valid, you know, and answer it seeing how they answer it is like, Okay, well, you know, you don't know what to do clearly.
Yeah. Sometimes you just gotta crank up that that current limit. Yeah.
Feel around? Whoa, that's hot.
Depends on depends on if the board is is something that you need to salvage or not, right, right, yeah. Like, is it one of a kind? Or is it like, oh, it's one out of like, 10,000. So you can just do some no RMA debugging.
Or somebody threw this in a pile of of like, fix it later things and it's four years down the road. And and your engineering manager is like, Hey, can you just look through this bucket and see what salvageable Yeah, so that's one of those situations where it's like, yeah, maybe you do just crank up the current limit.
Yeah. Try to get through as fast as you can.
Exactly. But I wasn't being able to discuss it like we are right now. That would be fair. I would love to have that kind of a conversation.
Yeah, that kind of conversation with the person you're interviewing. Totally. Yeah. Yeah. That was the that was one of the first things I did back at dynamic person. option is chew through
was true through the the basically the bad boards that we would get from the CME because we had, there was like years of inventory. And most of it was, yeah, the bone pile was pretty big. And most of it came down to actually component failures. Oh, wow. Yeah, that we were using these tax witches that really long actuators like a six millimeter tax which with like a 20 millimeter actuator on it. So big ol stick and the stick would the tax which would just be failed, just be bad. Yeah, just wouldn't work. I never figured out if it was like a manufacturing defect or is just bad parts. Given that I've never saw any flux or anything, I was just assumed as a bad part, they were pretty cheap parts.
I've got I've got a quick tangent that is like about tax, which is that I've never experienced this until working where I'm at. And it's a really odd one. We have a device that we build that has some light pipes on it. And these light pipes need a small amount of superglue to just hold them right in place. It's not it's not the worst, it's not the greatest. What we found is, you know, our operators would use a toothpick and they just put a small amount on the on the little doubt in place and then finish the build. Well, okay, so these light pipes are physically located close to a tax switch. And we found that if they put superglue on the on the the light pipes, built up the module, put it in its bag, and then put it you know, in like a on the shelf, we would see a large amount of failures in the tack switches when they get the testing. But if they would build it all up and just let them sit on the table and out gas, then the tax. So the the the gas from superglue was corroding the terminals on tax which is inside of the tax inside. But but only when we put them in a little like bubble bag, you know? Yeah. So that's been I've never run into that like, oh my gosh, yeah, it's annoying. avoid, avoid adhesives at all, at all cost
as much as you can. Because you do have to wait for full cure. Yep. Yeah. I bet you if you looked at your that datasheet for that glue, there was a full cure rating. And you were just before the full cure.
Oh, 100%. And I mean, it's just, it's just Joe Schmo super glue, it's nothing special. It's like five minutes. But the bill of the build was was put the light pipes in, put it in a bag and go so like they would get super glue applied. And then 20 seconds later be in a semi sealed bag. Keep that in mind that like this. There's a there's 1000 ways your product can fail.
Yeah, there's one way your product works. Yeah. Yep. And the other way is a fail.
Is it? Right? Yeah. I you know, I mentioned that to do a lot of people at work is like, electrical engineers, we have a situation where we have to make a bazillion things perfect. And that that's considered acceptable. Everything else. Yeah, like, no, think about it. Think about how many placements are on your board. And all of them basically have to be right for it to be what you envisioned. The design?
That's true. Yeah. All those components have to be perfect. Well, they won't be perfectly put on they have to get the right spots.
But but all the traces on the board, all the inner traces, connect to the barrels of vias all have to be correct. All of it has to be correct.
That's why you haven't manufacturing tolerances, man. That's where your DRC is for. Yeah. Man, when you get cheap boards in and you look under the microscope, or like the drill hit registration.
Yeah. Yeah. Then there for sure.
Okay, back to the interview questions. So yeah, so I need to put together some tests for our applicants. Like I was gonna, like, basically automate it to like for data support. They'll just give me the link of like, what they uploaded. And I'm just gonna run a script to compare what they did to like, this master sample thingy that I've done. I think give him like, it'll do like a score rating like what's different or something like that? Who knows? Nice I'm automates stuff, right? Spend 10 hours designing that. So I don't have to like review test results.
Nice. Yeah, I think I'm gonna do I'm gonna post my schematic and my questions up on our Slack channel. this coming week, sometime this week, and and we'll see if, if anyone wants to take a stab at answering some of these questions.
Yeah, and we did do a previous podcast about resumes like just the resumes Yep. I don't remember what episode that was, but we'll totally link it in the show notes. So that people who are listening to this can go listen to that one. If you're applying to engineering, I would say this applies to pretty much most engineering places you're applying to.
You know, out of all the interviews I've I've had, I would say probably 50% of them have some form of a exam style thing. Some of them are just you sit in a chair and you talk and the answer questions I've had. I've had some that, that they ask questions, they show pictures, ask questions. And I've had one where they gave me a marker and made me go up to a whiteboard and draw schematics and write equations.
I had to draw the what the depletion zone of a MOSFET look like. Wow, that's cool. Yeah. That was for Intel. Oh, nice. That was a so that was a weird interview. It was six hours long. For a technician position at like, the r&d Intel facility up in up in Austin, Texas. Yeah. And I was a year and a half in on my E degree. So I've been I've been at school for three years at that point, I think something like that. Yeah, that sounds like three years at that point. And this is like for a summer internship position. So internship position six hours, and I'm like, on the whiteboard, John depletion sounds like trying to remember what that looked like. Like the whole like, cross section, cross section and like, yeah, where like, the holes would be and stuff like, yeah. And the guy was asking me like, What material would you dope it with? And I'm like, Oh, shit, arsenic. Right.
That's fun. I
rarely racking my brain. Um, anyways. Yeah, I actually got the internship. But, but only if I would work there for a whole year. I would have to quit college to work at Intel.
Oh, okay. Yeah. Give them a solid chunk. Yeah.
Yeah. Because they wanted me work full time. I'm like, I can't work full time in, like in the summer, I can work full time. Yeah. I can't do that for a whole year, because then I'd have to quit school for a year. So I ended up turning that position down. But yeah, that was that was the most intense interview I've ever done. Everything after, that's like a cakewalk.
I had I had an interview once. Well, I had been interviewing with this company for about a month. And then they flew me out. I stayed at a hotel, see, yeah, I stayed in a hotel, and then got to their location at nine o'clock in the morning. And then I got back to my hotel at nine that night. And I had to I had to catch a flight early the next day. They gave me a full day. But I interviewed with virtually every engineer. I interviewed with the marketing guy. I interviewed with a test guy I interviewed with the CEO. I did lunch and dinner and beers with the engineering team. It was like it was a job, huh?
Did you get the job?
I got I actually got Yes, I did get the job. I did. But I shouldn't laugh about it. But I turned it down. It was this was one of those ones where like, it would have been a really fantastic job to take. But it had it had a lot of things that were just not right for me. Actually, you know, it's funny, one of the
same says that Intel job. It's like Sal, it's amazing opportunity. But it's like I had to spend a year not studying and that's actually what you don't realize is like if you believe like it's hard to get back Get into that mindset,
huh? Yeah, yeah. For sure. All right, well, I hope we gave some good information for those who are either currently interviewing or about to interview.
I have a huge list of interview questions. Yeah. It's like a page and a half long.
Do you just ask a few? No, I
think I'm gonna publish them on my I think I'm gonna publish them and the tests that I'm thinking about coming up with on my website. Oh, there you go. Because, because no one's gonna look that shit up.
And guess what? They did? Like they did that's
exactly. They studied.
Yeah. If they listen to this podcast, they listen to this podcast
Okay, so that was the Mac fab engineering podcast. We're your host, Parker Dolman
and Steven Gregg. Later everyone take it easy
Thank you, yes, you our listener for downloading our podcast. If you have a cool idea project or resume to send. Let Steven and I know Tweet us at Mac fab at Longhorn engineer or at analog PNG or emails that email@example.com Also check out our Slack channel. You can find it macro lab.com/slack and also the live stream is twitch.tv/macro Fab six o'clock central time. Usually on Tuesdays. This one was on Monday. What are you gonna do