Searching for Prior Art vs Making it from Scratch

Pre-Internet we still did "prior-art" searches, but it was done with our extensive personal libraries, asking around, and our memory - i.e. "I kind of remember a circuit like that in XYZ publication from 10 years ago, better look it up..." Bag-per-time-buck ratio was rather poor with these methods.

There isn't much that can't be built with basic building block circuit or ideas from other designs, so it would be pretty foolish not to spend a fair bit of time researching first. How much time?, how long is the proverbial piece of string? But Google and Google Group searches take minutes, and have a massively huge bag-per-time-buck ratio, unthinkable pre-internet.

Patent searches really aren't worth the virtual paper they are written on, so I usually don't waste my time there unless there is a specific commercial reason.

The funny thing about these days is that not only can you find the building blocks you need in minutes on the web, but often find you'll be able to do almost the entire job with commercially available gear in some way shape or form. A lot of Engineering is off-the-shelf these days.

Dave :)

BANG for the buck.

Oops What the hell were my typing fingers thinking? I may need some sleep...

Dave :)

On 7 Jan 2007 00:22:49 -0800, "David L. Jones" wrote: [snip]

Often I can't understand the "pantentese" and just resort to looking at the schematic. In general, I've tried to make it a resource for design development but it hasn't been very productive for me. On one odd occasion I did find and used.

My assumption is that the majority of patents should be good ideas and worth a peek. But now... I'm re-evaluating that assumption.

D from BC

I worked for EMI Central Research for a while (1976-79) and got my name on two patents while I was there - the organisation had a large group of tame patent lawyers, and people were encouraged to patent anything they thought might be patentable.

The engineers who were working on practicable projects didn't have much time to waste on generating patent queries, but there were groups of impractical engineers working on daft projects who did very little else. You can imagine how useful the average EMI Central Research patent was.

EMI always did have a reputation for patenting anything and everything in sight.

Strange thing to say, I haven't found that to be the case at all. Certainly useful ideas of how to go about something are often out there, but it's rare that an existing design can just be dropped in. And even if one only has to be changed a little, which I think is rare, but let's address it, then you'd better damn well completely understand it and do all the calculations, at which point, what's the sense in not starting over with new parts and even a new approach?

Bill Sloman said "impractical engineers" - LOL

-Dave Pollum

I often research existing *products*, from a price/performance standpoint, but seldom look for circuits. Architectures can be interesting, things like DDS synthesis or Cordic algorithms and such, but not specific circuits. As Win says, design, don't copy.

Manufacturer's "reference designs" are often crap. The real reason to look at them is because that's where they sometimes hide the part gotchas. Like, what's that big schottky diode connected to that ADC for?

The real thing to watch out for is when some SOB like JT designs an IC that blows away your lovely made-from-parts circuit design, and you're reduced to buying and soldering down chips.

John

Sno-o-o-o-ort! Fortunately the coffee cup is empty ;-)

I haven't done any "jelly-bean" parts in quite a while.

Most of my recent designs are reductions of substantial sections of a PCB into an ASIC.

This type of part rarely, if ever, reaches the general market... the client did it for a product competitive advantage.

I have occasionally had clients sell the ASIC's on the open market when they are about to introduce an even smaller version ;-)

...Jim Thompson

Or an oprnery old teacher with a thick wood ruler to smack your hand for mistakes like that! ;-)

I belief that the more one knows...the more of an effective solution can be created. So I spend an excessive amount of time checking the net for what's been done before.

For example....how about that poster trying to make that chirping circuit.. If all he knows is logic chips then the solutions are in terms of...logic chips... If he knows microcontrollers...then a bunch of logic chips suck.. If he knows what gizmos exist on ebay....then that could be the best idea. "If your only tool is a hammer then all your problems look like nails"..

I'm starting to think I should "build it with what I know". And forget that maybe somewhere in a million magazine articles exists the same design. I could lighten up on the checking and get the joy back and do it my way :)

Besides for understanding some electronic designs, it reminds me of assembly language.....without the source code, it's painful to understand the design. Starting from scratch does sound good.

D from BC

Patents are deliberately written to make it difficult to understand. The info is all there, but it's designed to be undigestable by your average human. Schematics are often redrawn in ridiculously unorthodx ways to make them difficult to follow. That's why I don't bother including them in my general searching, you can almost never find anything useful with a cursury glance.

Dave :)

...

Are you feeling a bit oprnery today, Michael? ;-)

Cheers! Rich

OK, that's a good example of a special case, I'd probably check out existing circuits as well.

Yep!

Yep!

Depends on what part of Engineering you are involved in. In general, in many areas I have found that there is more useful off-the-shelf stuff available today than there was say 15 years ago. Be it modules, or commercial or industrial products that can be hacked for one-off projects or whatever. But then again, it could just be that the information revolution has made this stuff much more readily found now?

True, although I'm not really talking about the product circuit design level, more about application level engineering, which depending on your industry might be all that is required. For instance, if I needed an RF link I wouldn't bother designing my own RF stuff unless the product or application demanded it.

Want to remotely switch a test jig on-off? - no need the design anything, just hack a $5 garage door remote. I can't even buy the switch from Farnell for $5 :->

Time, money, resources, the usual stuff you never get enough of! :->

Dave :)