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Electronics => Projects, Designs, and Technical Stuff => Topic started by: 5321488 on May 23, 2018, 09:40:38 am

Title: How often does something you put together work first time?
Post by: 5321488 on May 23, 2018, 09:40:38 am
 :palm:
Title: Re: How often does something you put together work first time?
Post by: srce on May 23, 2018, 09:51:16 am
No 0% option?  :palm:



Even your poll is a fail.  :P
Title: Re: How often does something you put together work first time?
Post by: TheAmmoniacal on May 23, 2018, 09:53:44 am
Yeah, needs a 0% option.
Title: Re: How often does something you put together work first time?
Post by: Miyuki on May 23, 2018, 09:54:03 am
How to count if it work like a firework  >:D
Title: Re: How often does something you put together work first time?
Post by: Seekonk on May 23, 2018, 01:27:59 pm
I just built something and forgot to make one connection.  This lead to an interesting result.  It is now a selling feature of the product that can be switched in and out.  Just like code, the faster you can bang something out the better.  The sooner you get something put together and playing with it the better.   
Title: Re: How often does something you put together work first time?
Post by: rmacintosh on May 23, 2018, 01:43:53 pm
Just built and tested an EEPROM I added to my project.
Absolutely did not work first time.

Or the second,  |O

Third time was a charm  :-+
Title: Re: How often does something you put together work first time?
Post by: xani on May 23, 2018, 03:33:59 pm
All the time, it just works. Just it doesn't work in a way I wanted to. Others call it bugs, I call it accidental features ^-^
Title: Re: How often does something you put together work first time?
Post by: Ice-Tea on May 23, 2018, 05:08:05 pm
My company's called FTR&F

First Time Right & First Things First

But yeah, 0% option required  :-DD
Title: Re: How often does something you put together work first time?
Post by: Mr. Scram on May 23, 2018, 05:35:28 pm
Works as in gives signs of life, works as in doing kind of something that resembles the final goal or works as in doing exactly what it should do?
Title: Re: How often does something you put together work first time?
Post by: ajb on May 23, 2018, 06:23:03 pm
Never, if there's software involved.

(These days, there's usually software involved)
Title: Re: How often does something you put together work first time?
Post by: maginnovision on May 23, 2018, 07:43:30 pm
100%. After some testing I find things could be better though and do it again. That's about... 40% of the time. MCU works but oops footprint is wrong and the data line got connected to a ground. Video amp works but the SD lines are backwards. Everything works but had to run wires because the sram footprint was 50% the length it was supposed to be. I get 5 amps but the lack of a tvs diode causes the controller to be fried when connecting to supplies less than a few hundred USD.

💯
Title: Re: How often does something you put together work first time?
Post by: David Hess on May 23, 2018, 09:22:05 pm
Up until a certain point, every project required significant rework.  After that point, every project at least recognizably worked.
Title: Re: How often does something you put together work first time?
Post by: tszaboo on May 23, 2018, 09:25:19 pm
Last time I put something together it was a sandwich and it worked for me. Otherwise, I design stuff, not banging rocks together. The last mistake I made was swapping MOSI and MISO on an SPI bus on a prototype, and it had to be bit banged. Who cares, we correct it for the second prototype.
Title: Re: How often does something you put together work first time?
Post by: Buriedcode on May 23, 2018, 10:26:33 pm
Most of my career would be about 10% but in the past few years its shot up.  This is mostly because I'm doing simpler projects, and I have become better at testing/debugging on the fly (as I'm sure we all work in a modular way).  And of course, using MCU's, if one has built up their own software libraries that have the bugs ironed out over time leads to less traps.

But I agree with some of the comments - depends on what you mean by "work".  If you have a vague goal, such as "light this LED if I get a signal from something" then chances are it's going to be easier to achieve than "get 32 wireless devices on a mesh network in the field".

Aside from quite simple projects, does anyone just knock something up without simulations or tests and power it up without checking anything first?  I would have thought most of us would have done that perhaps when we were starting out, but quickly learned that breaking the problem down into smaller parts, that each can be tested is a more reliable and quicker way to achieve a goal.  This greatly increases the chances of things going well first "power on".

Title: Re: How often does something you put together work first time?
Post by: jpanhalt on May 23, 2018, 10:43:32 pm
I don't give it the option of not working.  Simple.
Title: Re: How often does something you put together work first time?
Post by: Mr. Scram on May 23, 2018, 11:29:46 pm
Last time I put something together it was a sandwich and it worked for me. Otherwise, I design stuff, not banging rocks together. The last mistake I made was swapping MOSI and MISO on an SPI bus on a prototype, and it had to be bit banged. Who cares, we correct it for the second prototype.
You're a braver man than I am, spitting in Murphy's face like that.
Title: Re: How often does something you put together work first time?
Post by: rdl on May 24, 2018, 12:28:49 am
Almost never...
Title: Re: How often does something you put together work first time?
Post by: ucanel on May 24, 2018, 02:15:41 am
%10 generally.
%50 If it is very simple circuit.

%0.1 magic smoke.
Title: Re: How often does something you put together work first time?
Post by: Rerouter on May 24, 2018, 02:19:47 am
Comes down to how long I sat down and went over all the stupid things that could go wrong before ordering the boards,

My last 5 big projects have all worked out of the box (40-280 components), with minor cosmetic issues, e.g. a screw hole not giving enough clearance, or no indicator for what way the programming header connects.

My last 5 hobby projects have had issues, but learnt enough about some weird reactions that now I have a new profitable project coming up.
Title: Re: How often does something you put together work first time?
Post by: Cyberdragon on May 24, 2018, 04:22:10 am
I left a project working for months untill it started acting funny. I noticed it started and died when shaken. There's very few components (lots of wires though) so I though it was either the pot or a bad solder joint.

How about a missing solder joint. :palm: Good thing it was on the low voltage side not the mains side. ::) :-BROKE
Title: Re: How often does something you put together work first time?
Post by: IanB on May 24, 2018, 04:35:34 am
Generally when something doesn't work as designed it is because there is something you didn't properly understand about what you were doing.

As you get older and gain more experience the percentage of things that work first time grows ever closer to 100% as you learn more and more about how things work.

You have to distinguish between designs (that are supposed to work) and experiments (where you don't know what should happen and you are exploring). However, it is often said that failed experiments are just as valuable as successful ones. Every experimental result increases your knowledge.
Title: Re: How often does something you put together work first time?
Post by: cat87 on May 24, 2018, 06:31:57 am
Almost never. Whenever I make a small circuit on perf board,  if I think it's going to take me 1 hour to put together and make it work, that means it usually takes half a day.  Murphy likes to get his nose into my business.
Title: Re: How often does something you put together work first time?
Post by: Mr. Scram on May 24, 2018, 07:18:13 am
Generally when something doesn't work as designed it is because there is something you didn't properly understand about what you were doing.

As you get older and gain more experience the percentage of things that work first time grows ever closer to 100% as you learn more and more about how things work.

You have to distinguish between designs (that are supposed to work) and experiments (where you don't know what should happen and you are exploring). However, it is often said that failed experiments are just as valuable as successful ones. Every experimental result increases your knowledge.
"Things work first time when you have more experience" and other lies we tell ourselves. ;D
Title: Re: How often does something you put together work first time?
Post by: TheUnnamedNewbie on May 24, 2018, 08:40:47 am
It depends on the type of project, and in what setting. At home, sure, I often have stuff that doesn't work first time. But when doing designs at Uni, many of our chips work first time, but that is because we spent months simulating them. The performance might deviate a bit for analog designs and such. Our RF amplifiers are a special case though, since there we often push past what the simulation tools can do and need to start mixing multiple tools (3D EM solvers and SPICE and ...) and can't simulate the entire design because it would be too complex.
Title: Re: How often does something you put together work first time?
Post by: Dubbie on May 24, 2018, 10:20:27 am
My current project was a first for me. The assembled pcb worked first time, and what is more astonishing, the firmware I wrote while I waited for the boards, flashed and worked first time as well.  It was a relatively simple board with about 40 components and an stm32

I think the main thing that made my PCB strike rate go way up was The Fedeval Academy video about making boards that work first time. I have a checklist I run through now which catches most dumb errors.
Title: Re: How often does something you put together work first time?
Post by: mavu on May 24, 2018, 11:12:15 am
Needs a 50/50 option, because it certainly feels like 50/50 :)

But I suspect its less than that, because I'm always excessively happy when something works the first time :P
Title: Re: How often does something you put together work first time?
Post by: BradC on May 24, 2018, 11:56:03 am
As you get older and gain more experience the percentage of things that work first time grows ever closer to 100% as you learn more and more about how things work.

I find this, but it's more than just learning about how things work. I also find the older I get the more theory I sort up-front, and the more considered my approach (read - slow).

I was astonished recently when lashing up an uC centric bit of kit after spending a day or so writing the prototype code to find that both the software and hardware worked first go. I shouldn't have been though. 20 years ago I would have done 40-50 crash and burn cycles putting it all together and getting it working. Now I spend that time drawing, documenting and reading about gotchas in the data sheets. Same time, same result, less solder and less time in front of the compiler.

Title: Re: How often does something you put together work first time?
Post by: m98 on May 24, 2018, 12:13:32 pm
Most of my problems are actually weird manufacturing defects or some crucial hints burried deep down in a datasheet.
Just recently had a prototype where the uC won't respond to the programmer. Turned out that despite the otherwise beautiful solder joints, one pin of the uC wasn't properly soldered, the reset pin. That was literally the last thing I had suspected.
Title: Re: How often does something you put together work first time?
Post by: basinstreetdesign on May 24, 2018, 05:14:58 pm
 ::)  In 30 years it happened to me ONCE.

I was working for a small company when the marketers came to me with an idea for a gizmo they thought would be a good addition to the product line.  How long would it take to make a prototype of it so it could be demo-ed to a customer who also seemed to be interested, I was asked?  I thought for a few minutes and after a couple of doodles on one of the ubiquitous quad-ruled notepads, said I could have one working in about four weeks.  I figured one week to design the circuit, one week to hand wire the proto and two more weeks to debug it.  That sounded reasonable, at the time.  And fairly generous on the debug time.  The plan was, I would have the able assistance of a technician, John, who would make the prototype by hand, then we would both debug it together.

I spent the next week ruminating and drawing out a circuit design on paper (this was before PCs were a common feature of the desk-top landscape).  I tried my best to think of everything.  I gave it to John after I had given up trying to think how it could fail.  He went away and I didn't see him for the next few days.  When he came to me, late into the second week, I expected to hear about a long list of weird behaviours or even that it did nothing, but what he said made me nearly fall off my chair.  He said “It works!”.  “What do mean, 'It works.'?”, says I, flabbergasted.  “It works”, says he.  “Just the way it's supposed to.  In every mode!”.  I didn't believe him, of course, so I went to see it for myself and there it was doing what it was supposed to do and doing it very happily.

I only saw the unit that once.  After that it disappeared into the hands of the marketers.  I don't think it was ever manufactured.  However it did have a profound effect.

They started expecting me to do it again.  ::)  I became known as the guy who could design a machine from scratch, on paper and make it work with no debugging, on the first try.  For months after that I had to work against the tendency of the marketers and some management types to expect me to come up with prototypes in record time.  For me this was worse than being known as someone who's stuff was a little bit late.  (Not a lot late.)

Moral: Always use up your allotted design time even if you don't need it. :palm:
Title: Re: How often does something you put together work first time?
Post by: Pack34 on May 24, 2018, 05:46:36 pm
Define "work". Can function to spec without any modification or could it require a small change, jumper wire, etc?

I would say that >95% of my work will function the first time but whenever you're doing something new there's always that small change that's needed before I would be comfortable with a production release. That's why I always prefer to next-day some bare boards, hand-pop, then I can find those little odds-and-ends that need to be polished before I can put in that order for 250 eaches.
Title: Re: How often does something you put together work first time?
Post by: Cyberdragon on May 24, 2018, 05:56:00 pm
Generally when something doesn't work as designed it is because there is something you didn't properly understand about what you were doing.

As you get older and gain more experience the percentage of things that work first time grows ever closer to 100% as you learn more and more about how things work.

You have to distinguish between designs (that are supposed to work) and experiments (where you don't know what should happen and you are exploring). However, it is often said that failed experiments are just as valuable as successful ones. Every experimental result increases your knowledge.
"Things work first time when you have more experience" and other lies we tell ourselves. ;D

Then there's times when you have some intuition and just fiddle with something and accidentally get it to work yet you still don't fully understand what's going on.

It's like those mechanical puzzles when you accidentally open it and go "what did I do?"
Title: Re: How often does something you put together work first time?
Post by: Leiothrix on May 24, 2018, 11:04:00 pm
Talking about software here as that's what I do more of:

Sometimes I'll write a page or two of code that does something.  Then it compiles and runs perfectly and the program does exactly what it's supposed to.

That always makes me suspicious of what I've missed rather than happy though  :-\
Title: Re: How often does something you put together work first time?
Post by: james_s on May 25, 2018, 04:11:00 pm
It depends on how you define "works". Most of my projects these days do something the first time, but for a new design there's almost always some tweak I need to make. On a bad day I realize I swapped a couple of the pin names when creating the schematic symbol and that issue went all the way into the first run of PCBs. More often I find I need to tweak the value of a couple resistors. Occasionally a project is simple enough that it all just works right way but then if any sort of software is involved my code almost never works on the very first try. Always there's at least one typo or some other bug. I've never met anyone who could hammer out a whole program and have it work right off the bat without any bugs though.