EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: rocketfire on December 24, 2014, 09:52:53 am
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Do all you professionals, semi-professional and hobbyists just keep making your own footprints?
One day into kicad I got so frustrated with a lack of components in the library. No ltc44*, how about a tsot; nope, how about 0805 phototransistor; nope. Only the most basic parts in the library.
Ok, I'll swap to eagle, they're linked in with Element14 so it must be better, nope.
I'm only two days into learning PCB design software so it could be me, please tell me something obvious that I'm missing.
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You found the weak spot of all cad tools.
They give you a base library and that's it. There simply are so many packages out there it is impossible to keep up.
And even of you think you got the right So8 footpri t.. They can differ from manufacturer to manufacturer... Ran i to trouble the other day with a ti part. Labeled so20 (so wide ), no , it's inbetween the width of an so14 and so20... Dammit.
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everytime i design something, 20% of the time spent in eagle is googling keywords "part-xyz eagle" and downloading libraries ;) so it's not just you, it's normal :D
you only have to make your own footprint for some "exotic" parts, because many guys are making libraries and sharing them with the rest of the world (and therefore once you make your own library for an exotic part, please share it as others do).
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Just make your own symbols and footprints. It takes about as much time to make them yourself than trying to find them from somewhere.
After I started making my own I've had like zero problems with footprints or symbols. Libraries made by others are often just plain incorrect or mislabeled.
A tool like http://www.pcblibraries.com/LibraryExpert/ (http://www.pcblibraries.com/LibraryExpert/) is extremely handy, just insert package dimensions and plop out comes IPC7351 compliant footprint you can import to your EDA-tool. Literally takes like thirty seconds per footprint.
One thing I've also noticed is that NEVER trust the "recommended footprint" from datasheets. You'd think the manufacturer know what kind of footprint is good but very often... nope.
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Sometimes some parts are well hidden in the Eagle libs or you find only the matching package, but it's easy to create your own parts. I've made a few personal libs with my favourite stuff. Or, as already mentioned, you can find tons of eagle libs in the web.
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Thanks guys for the feedback and the tips, at least it wasn't me missing something obvious. It does seem a huge duplication of effort. So many people would have their own libraries for something that could be done just once by the manufacturer. Maybe I'm just too green and my glasses too rose coloured.
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I use diptrace and have had to create footprints of slightly odd parts. so called SO or SOIC parts scare the crap out of me because it's such a generic terms and it can mean any number of things so I have been known to take the mechanical drawing of the datasheet and create a footprint to match exactly and give it the parts part number.
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There are better Eagle libraries available.
Sparkfun
https://github.com/sparkfun/SparkFun-Eagle-Libraries (https://github.com/sparkfun/SparkFun-Eagle-Libraries)
Adafruit
https://github.com/adafruit/Adafruit-Eagle-Library (https://github.com/adafruit/Adafruit-Eagle-Library)
Seeedstudio
http://www.seeedstudio.com/wiki/Open_parts_library (http://www.seeedstudio.com/wiki/Open_parts_library)
The biggest problem I have is that the search feature doesn't work or else I don't know how to work it. I end up downloading a search tool for my PC and search the library by brute-force full text file search.
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There are better Eagle libraries available.
Sparkfun
https://github.com/sparkfun/SparkFun-Eagle-Libraries (https://github.com/sparkfun/SparkFun-Eagle-Libraries)
Adafruit
https://github.com/adafruit/Adafruit-Eagle-Library (https://github.com/adafruit/Adafruit-Eagle-Library)
Seeedstudio
http://www.seeedstudio.com/wiki/Open_parts_library (http://www.seeedstudio.com/wiki/Open_parts_library)
The biggest problem I have is that the search feature doesn't work or else I don't know how to work it. I end up downloading a search tool for my PC and search the library by brute-force full text file search.
first of all tick the "description" check-box in the add dialog, and enclose your search term in asterisks ;) e.g. add *3904* will yield all parts with 3904 in them.
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I have been considering deleting all the libraries in Kicad and making my own as I go just so I know I have the right footprints.
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Don't delete them, just create your on in a different location so a uninstall/reinstall wont delete them.
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After it happened to me a few times that the footprint I got from an eagle library wasn't exactly what I thought it would be, I know make all components myself, which has removed that source of error. As an added bonus, you can more easily make small modifications to the foot print, to make them work better with the solder method you're going to use (e.g. make pads a bit longer if you hand solder, so you have room to place the iron tip.)
I learned not to implicitly trust 3rd party libraries (actually, not even the ones supplied with eagle, although they are better.) I found wrong descriptions, imprecisions or plain mistakes in the footprint layout every so often. Hence, double checking everything myself is required, and at that point, I might as well just do the whole thing myself.
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That's what I did in Diptrace. There were too many I knew I'd never use and the ones I did try often had errors or quirks I didn't like. When I realized how trivial it was just to just create your own, that's what decided to do.
I have been considering deleting all the libraries in Kicad and making my own as I go just so I know I have the right footprints.
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It does seem like duplication of effort, but creating your own is a good learning experience.
Possibly more importantly is that your personal library is limited to what components you use and is arranged to your way of thinking. This is nearly always more efficient than trying to wade through someone else's ideas of organisation.
Connectors et al, though are a different matter - I'll copy those when I can find them.
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DipTrace actually has a really strong set of footprints built in. The trick is to always use the measure tool to compare pin spacing with the mechanical data at the end of your datasheet. This way you don't get burnt.
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they are also unusually organized and hard to search. Library management is the single largest failure of diptrace and they claim to be changing it.
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Thanx for your fine Artwork!
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I meant to say dip trace in my post above that has now been corrected
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they are also unusually organized and hard to search. Library management is the single largest failure of diptrace and they claim to be changing it.
Search works fine as of the latest major version. As for the way footprints are organized I don't see any huge problems. Diodes are under diodes, SMD under SMD, caps under caps, etc.
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