PCB Layout Software???

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Mike6158
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PCB Layout Software???

Post by Mike6158 »

I've been trying to find a decent software package for PCB layout. In a perfect world the software would let me build the circuit from a list of components and then build the PCB from the circuit. I've looked at Circuitmaker and Livewire (demo version). Circuitmaker was nice but a bit pricey for my needs. As good as it was it didn't have an NE558 or an IR detector in it's library. I'm not familiar with SPICE otherwise I suppose that I could buld my own.<p>Livewire was pretty cool and the price isn't bad. It didn't have a very large library but it's pretty good considering the price. I didn't test drive their PCB layout software.<p>Any other options out there???
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Mike
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Re: PCB Layout Software???

Post by Mike »

You can't find software better than Eagle Layout Editor, www.cadsoft.de or at least I haven't<p>Freeware version avalibale (for personnal, non-profit use with board size limit) or you can purchase a full version.<p>it's easy to use and free.<p>[ November 12, 2004: Message edited by: Mike ]<p>[ November 12, 2004: Message edited by: Mike ]</p>
redrocker
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Re: PCB Layout Software???

Post by redrocker »

Just keep in mind about Livewire that to produce gerber files you have to purchase the more expensive version.
Mike6158
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Re: PCB Layout Software???

Post by Mike6158 »

Ok Thanks... I'll check out Eagle Layout Editor.<p>I'm afraid that I don't know what a Gerber file is... But I'm willing to learn :D
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."
redrocker
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Re: PCB Layout Software???

Post by redrocker »

The quick, unscientific, practical definition of "gerber" files are that they are the CAM (computer aided manufacturing) files produced by layout software you send to board houses to have the boards built for you as opposed to building them yourself at home. I am no expert in this arena, but a few months ago I also looked at purchasing the hobbyist version of Livewire for $50, but I intended to have my boards built for me, so I knew I needed CAM capability. The hobbyist version does not produce CAM files, but the Pro version does, and it costs significantly more. I finally went with AutoTrax for $50 because it does produce CAM files, and I have been pleased with it.
wd5gnr
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Re: PCB Layout Software???

Post by wd5gnr »

If you want an Eagle tutorial, as well as info on how to make your own boards or send Gerbers out to be made, have a look at:
This book in the N&V Store<p>73
rshayes
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Re: PCB Layout Software???

Post by rshayes »

Gerber files are a historical artefact. The "Gerber" refers to the Gerber photoplotter. This was a large X-Y plotter that moved a light source over a sheet of photographic film. The light source had several sizes of apertures, usually either round or square. It also had a shutter to cut the light off entirely. A series of instructions would draw a line by positioning the exposure head at a start point, selecting an apeture, opening the shutter, moving the exposure head in a straight line to an end point, and closing the shutter. These instructions were probably stored on punched paper tape or punched cards originally. Modern machines use raster scanned lasers to do the exposure, with a computer to translate the Gerber file to a raster scanned format. Practically all printed circuit manufacturers are set up to work with Gerber files, even though the files have little relationship to the way the image is actually generated now.<p>One company (www.expresspcb.com) supplies a schematic capture and PCB layout program as a free download. This does not generate Gerber files, so you have to have them fabricate the circuit board.
rshayes
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Re: PCB Layout Software???

Post by rshayes »

For printed circuit layout, you don't need to deal with SPICE. It is a circuit analysis program.<p>The first step is "capturing" the schematic. There have been several programs for this, Orcad is one example. The schematic capture program creates a netlist, which describes the interconnections between the parts as wires connected between numbered pins. There are quite a few netlist formats but most of them are fairly simple.<p>A netlist can be fed to two types of programs. One type combines the connnections described by the netlist with models from a library and generates a SPICE file. A version of SPICE can read this file and do an electrical analysis of the circuit. The output file from SPICE can then be fed to a plotting program which displays the information.<p>The second type of program accepts the netlist and combines it with files from a library that describe the physical dimensions of the pads for each part. Traces are added to the file by either a manual editor or an autorouter. The output of this program is usually a Gerber file.<p>These analysis program and the layout program are independent of each other. You can do an analysis without doing a layout, or you can do a layout without doing an anaylsis.<p>Most layout programs include a part editor so that you can generate layouts using non-standard parts.<p>Most of the low cost versions limit the total number of pins used in the circuit. Limits of about 600 pins are common. A moderate size board can easily exceed this.<p>[ November 15, 2004: Message edited by: stephen ]</p>
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haklesup
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Re: PCB Layout Software???

Post by haklesup »

My generalized advice:<p>A good library is important but even the best are incomplete. So, what's really important is a good library editor that makes sense to you and is not wrapped up in too many layers of files. A via or thruhole wizard is helpful also.<p>Simulation sounds cool and can be quite useful at times but it is only as good as the models used. If your program comes with a model in the library, great but if it dosent, its real hard to find free models anymore on the web.<p>For ease of use (intuitive), you want a windows like interface but for efficiency, power and flexibility, most CAD programs really need a more traditional DOS like interface which used many keyboard commands. <p>
If you desigbn simple boards infrequently, a free program like PCB123 which is tied to the manufacturer will simplify the exchange of files but it is better to learn what files the Fabs expect. <p>A gerber file is a plotter file that describes one single layer in a PCB design. Usually you will have a file for each of these layers;
Copper Top, copper bottom, silkscreen top, soldermask top and bottom, plated thru holes and board outline. Additionally there are a few other milling files which describe any cutouts and the board shape and a drill file with the drill sizes and locations. Finally, and optionally (but highly recommended) is a Fab drawing which can be PDF, JPG or DXF which shows the board outline, dimensions and any manufacturing notes, tolerances and unplated hole and cutout locations.<p>Check this one out also www.cadint.com I used this one for years and only truly came to appreciate it when I bought and learned UltiBoard 7
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Bob Scott
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Re: PCB Layout Software???

Post by Bob Scott »

All,<p>I have tried the free version of the Eagle 4 capture program for schematics but I have not tried the layout software. Apparently the layout software limits you to just a few square inches of board and two layers. Does anyone know if silkscreen layers and solder mask layers count as used layers in the free version? I mean, make 2 solder mask layers, no copper layers and you're done? You can't go any farther? That would be useless.<p>Bob :cool:
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Dave Dixon
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Re: PCB Layout Software???

Post by Dave Dixon »

Hi Bob,
I use the pay version of Eagle, but a quick check on their website shows that the freeware maximum board size is 4 X 3.2 inches and 2 SIGNAL layers max (Top and Bottom). You can have solder masks, silkscreens etc. for top and bottom, but they don't support multilayer boards. Freeware, with an autorouter - can't beat it. Good luck,
Dave
Oh yeah, the free version won't let you have multiple sheet schematics... like you need that for a 4X3" PCB!!!
Mike6158
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Re: PCB Layout Software???

Post by Mike6158 »

Thanks for all of the replies. Since I posted this I have been test driving a few different programs. It looks like I need to "drive" at least one more. <p>Thanks to those that replied here I understand what I am looking for now. <p>Cadsoft's Eagle program seems to be pretty good albeit a little tough to learn (especially for someone like me that doesn't read the instructions unless absolutely necessary :D )<p>I'm in the process of building a robot. The design came from a book called Insectronics. I etched the boards for the bot thise evening. The main board went pretty well. The ultrasonic board is a little thin in places but it will work. All in all I'm pretty pleased with the results considering they were my first boards. I wasted a lot of board though. Next time I'll plan better. One of the things that I noticed about the author's (of the book) traces is how thick they are. Every software package that I used drew thin traces. I know that I can change the trace size in the software so I guess that it's just a matter of practice?<p>Thanks for the replies.<p>73
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."
Mike6158
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Re: PCB Layout Software???

Post by Mike6158 »

Well... I settled on Cadsoft Eagle. The freeware version is probably all that I'll need but just in case I was going to order their "non-profit" version. Has anyone here done that? Using a credit card (safely) appears to be all but impossible with them. Via email, they said that I can FAX my number to them :eek: That ain't happening. I guess it's snail mail and check. Odd that they are so far behin d the times...
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."
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haklesup
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Re: PCB Layout Software???

Post by haklesup »

On Trace Thickness:<p>If you are using a board house (Fab) to make the boards; 7mil is the thinnest you want to use because smaller will kick you into a higher price bracket.<p>Since 7 mil is still quite thin, I use 14mil or 21 mil for most of my signal traces and 30, 50 or 100 mil for most power connections not on a plane.<p>If you are making your own boards, most processes requires much thicker traces for good results. Traces published in a magazine would need to be quite thick to be useful. How thick? I have less of a sense of that since I always use a fab but 30mils seems like a good minimum on up to 200mil or so. <p>A similar discussion applies to trace spacing.<p>The program should have a place to set/save default sizes but may be set quite thin by default when you start using it.<p>PS. on the credit card issue. check with your card online account, you can probably get a virtual number assigned that is good only for that transaction. Makes it safe again.<p>[ November 22, 2004: Message edited by: haklesup ]<p>[ November 22, 2004: Message edited by: haklesup ]</p>
Mike6158
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Re: PCB Layout Software???

Post by Mike6158 »

Thanks for your reply. Board fabrication is new to me so your comments are very helpful.<p>73<p>Oh... good advice on the CC. I forgot about that option...<p>[ November 22, 2004: Message edited by: NE5U ]</p>
"If the nucleus of a sodium atom were the size of a golf ball, the outermost electrons would lie 2 miles away. Atoms, like galaxies, are cathedrals of cavernous space. Matter is energy."
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