My latest Eagle PCB.

[Zero999]

I thought I'd do a more complicated PCB.

The schematic is pretty simple, a ring oscillator with the LEDs configured so one illuminates after another but it's a pain to route. To make things more difficult for myself, I did it on a single side and didn't route between the pins on the IC or capacitors; if I were to make this PCB myself, I wouldn't have a solder resist which means there's a high risk of bridging where there are pins soldered close to neighbouring tracks.

I tried using the autorouter but it's rubbish, worse than A!tium's, in the end I did it the hard way. I didn't expect the autorouter to work because it probably wasn't possible given the way I had placed the parts; when I did it myself, I had to rearrange them.

I know it's probably possible to do a better job. I'm not completely satisfied with it and will have another go at it. I think I'll do a rough sketch first, then I'll place and gate swap accordingly.

[TheDirty]

I wouldn't have a solder resist which means there's a high risk of bridging where there are pins soldered close to neighbouring tracks.

Other people have said this too, but I've never found this to be the case.  If you get a bridge, use a bit of solder wick.

[Zero999]

Other people have said this too, but I've never found this to be the case.  If you get a bridge, use a bit of solder wick.

It's never happened to me before, but that's because I've never done it on a home made PCB.

Yes, I know it's fairly easy to fix but it's a huge risk, such a fault could damage a component, for example suppose a gate output was shorted to a power rail? The IC will burn out. Fair enough the 74HC04 isn't expensive but it's still a pain to replace.

Maybe I would do it if I had absolutely no choice and if I do it, I'll try to make sure I only do it with pins and tracks that won't physically damage components, if there's a short.

You might think I'm paranoid but I'd rather spend longer routing a board, than wasting time debugging or money on failed components.

[shodan]

could you post the project file ?
I'd like to give a shot at optimizing this layout

[TheDirty]

Yes, I know it's fairly easy to fix but it's a huge risk, such a fault could damage a component, for example suppose a gate output was shorted to a power rail? The IC will burn out. Fair enough the 74HC04 isn't expensive but it's still a pain to replace.

Why would you not see this before you put power to the board?  Especially on single sided where you can just hold the board up to the light and see through.

I've done many 0.5mm IC's on home made boards and even 0.4mm and for me it's a non-issue.

[Zero999]

I don't think much light will get through with all the components fitted to the other side of the board.

Anyway, here's the PCB and the schematic file, play with it as much as you like.

I've also posted a video of the circuit working on a breadboard, sorry about the quality and noise, I filmed it using my old digital camera which only does 320x240 and it wasn't possible to disable the sound. I'll probably never build the PCB though, it's just a learning exercise. If you do build it, the lights will flash more slowly than the video, the one I breadboarded used 100nF capacitors and 1M resistors.

[shodan]

Hi,

for fun I tried to optimise the board for minimum space
without using jumpers (because I don't know how to add them !!)

it's not really tidy, I can't find out how to disable snap-to-grid and weirdly some points are off the grid but I can only move them in grid units
I'm not really familiar for eagle or pcb layout, it's only the second one I've done (the other was ... 5 years ago .. already), I know from dave's video that the long trace that connects all the caps are probably going to catch lots of noise and stray capacitance etc.. but I just wanted to optimise for space, some tracers are probably way too close to holes

anyway, that was fun, a little puzzle that killed two hours and a half

[ArtemisGoldfish]

I wish I could figure out Eagle as you have, especially with a surface mount project on the horizon. I have Ultiboard (part of the NI Multisim suite), and at work they use PADS, but Eagle just seems to be the main hobbyist PCB designer...Guess I'll have to figure it out at some point.

Anyways, nice work. 

[andri]

I'll hijack this thread for my post, hopefully the OP won't mind

I just finished a small TTL serial to onewire adapter (largely based on the schematics here).

I think the board came out pretty neat-looking (nice and symmetric and the traces aren't too bad either, IMHO), although there isn't much room for labels and I still need to get rid of the pin numbers and such.

[Zero999]

Hi,

for fun I tried to optimise the board for minimum space
without using jumpers (because I don't know how to add them !!)

it's not really tidy, I can't find out how to disable snap-to-grid and weirdly some points are off the grid but I can only move them in grid units
I'm not really familiar for eagle or pcb layout, it's only the second one I've done (the other was ... 5 years ago .. already), I know from dave's video that the long trace that connects all the caps are probably going to catch lots of noise and stray capacitance etc.. but I just wanted to optimise for space, some tracers are probably way too close to holes

anyway, that was fun, a little puzzle that killed two hours and a half

Thanks for trying, but sorry it's a fail, there are two connections missing from the LEDs and ther are no power supply connections, especially Vdd  which is buried in the mess.

I wish I could figure out Eagle as you have, especially with a surface mount project on the horizon. I have Ultiboard (part of the NI Multisim suite), and at work they use PADS, but Eagle just seems to be the main hobbyist PCB designer...Guess I'll have to figure it out at some point.

Anyways, nice work.

Eagle is pretty poor compared to Protel but I don't know about Ulraboard, I've never hear of it.

It took me a day to figure out Eagle, I have attempted it a couple of times before but I always lost my temper after an hour or so. All I can say is persevere, although it's quite poor, it's better than nothing, it could be better than Ultreboard,  but don't count on it. I'll write you a brief tutorial, if you're interested.

EDIT:
I've sorted out the problems with the buried power supply and lack of connections to the LEDs. Although I've neatened it up a bit, it could still be better, I'll probably remove the capacitor values from the silk screen because it's not useful as all the capacitors are 10µF.

[shodan]

yeah I knew about the LED I forgot to mention I had run out of time and for the power supply lines well I started a new board and the pads didn't appear and I didn't know how to add just a pad so meh it was just for fun !

[Zero999]

I've found a keygen and a patch for Eagle which works.

I don't normally p1r8, apart from the legal problems, in this case I don't want to draw a large board which I'm going to use, then download and install the latest Eagle version only to discover there's no crack for it so I can't modify it because it's too large for the free version.

At the moment I'll just use Eagle for educational purposes. When I come to do a board I actually want to use, I'll hope to be using some better free software or I'll use the legal free version of Eagle to do it.

[TheDirty]

Unfortunately license information seems to be stored in the libraries, if not the .sch/.brd files.  That's what people are complaining about earlier.  Using a cracked copy is a good way to screw up your files.  Boardhouses that take Eagle files directly get this problem often, getting files from cracked copies that they can't open.

[Zero999]

Let's put it to the test.

I've created these files with a cracked version of Eagle and I don't have a problem opening them myself, can you or anyone else using a legitimate version of Eagle open them?

I don't care as long as I can open files I've created, as I said before, I'm only using Eagle for educational purposes. When it comes to doing a PCB for real I'll use something better. Still, it would be nice to know whether anyone else can open files I've created.

[Zero999]

I've just unpatched Eagle and the files created with the p1r8 version still work for me in Eagle lite. I didn't use any of pro's features which might have something to do with it but I would've thought it would still worked in view only mode, which is what the help file says.

Fortunately the crack I used backed up all the files so I didn't need to reinstall up unpatch. I've written a couple of batch files: unpatch Eagle.bat and repatch Eagle.bat which just rename files so I can switch back and fourth.

I think more investigation is in order, I'll try creating a board which uses pro's features and see if it opens in lite. To keep track of what I'm doing, I've created a new directory called p1r8 which will be for educational use only and I won't create files anywhere else with the pro version.

[alm]

They do routinely block new codes in future versions, so you might be unable to open your files in future versions. Better keep a backup of the current Eagle version around.

[TheDirty]

I've done the cracked Eagle to test and the problem I had was when I moved to a newer version.  The schematics I had done were screwed.  I had only done a few though so it wasn't a big loss.  Also I never go over the Eagle lite limits anyway so there's no point for me.

I do use A!tium as well, but I prefer Eagle for my personal designs.

[Zero999]

Did anyone try the files attached to my previous post?

It looks like I'll have to wait until the next version is released before I know if it's going to be an issue.

The crack I used is more than just a keygen, it patched the .exe files which might get round the problem for all I know.

Meanwhile I'll keep it legal for the PCBs I care about and will install to a new directory when the next Eagle version is available.

I wouldn't think getting the PCB made would be a problem since most places take gerber files? Not that this would bother me because I make my own PCBs with toner transfer.

I think that encoding the license number in files saved by a program is a privacy issue. I dislike proprietary file formats for this kind of reason; save your work in a proprietary format and it's effectively no longer yours: the party with the rights to the format now owns part of it. This is why I like open source software and programs which save in an open and transparent format such as OpenOffice.org and LTSpice.

Talking of toner transfer: I've notice a bug in the image export. When I export the PCB to an image it's always slightly larger than it should be. For example I have a 2.6"x2.6" PCB which I exported to a PNG with a resolution of 300DPI; this should give a 780x780 pixel image but it gives a 786x783 pixel image. This is a pain, I have to crop away the 1 pixel boarder around the outside of the board and scale to 780x780 before it's the correct size.

[TheDirty]

Did anyone try the files attached to my previous post?
...
The crack I used is more than just a keygen, it patched the .exe files which might get round the problem for all I know.

I have not tried it yet.  Just stopping in quickly between projects.  I'll try it by Monday.

I wouldn't think getting the PCB made would be a problem since most places take gerber files? Not that this would bother me because I make my own PCBs with toner transfer.

Yes there would be no issue exporting to gerbers.

Talking of toner transfer: I've notice a bug in the image export. When I export the PCB to an image it's always slightly larger than it should be. For example I have a 2.6"x2.6" PCB which I exported to a PNG with a resolution of 300DPI; this should give a 780x780 pixel image but it gives a 786x783 pixel image. This is a pain, I have to crop away the 1 pixel boarder around the outside of the board and scale to 780x780 before it's the correct size.

There's no physical size to an image.  The size that it prints out would be dependent on the resolution and your printer.

Not certain why you are exporting to a image. Print it directly and it's perfect.  I haven't used it, but you can print to PDF or PostScript as well if you really need to take it somewhere.

[alm]

I think that encoding the license number in files saved by a program is a privacy issue. I dislike proprietary file formats for this kind of reason; save your work in a proprietary format and it's effectively no longer yours: the party with the rights to the format now owns part of it. This is why I like open source software and programs which save in an open and transparent format such as OpenOffice.org and LTSpice.

Feel free to switch to Kicad or gEDA. The former is younger, but easier to use and with Windows binaries, it appears to develop quite fast. The latter is older (more features), but is not very easy to use, and doesn't distribute Windows binaries. Both are open source and have transparent (plain text) file formats.

[Zero999]

There's no physical size to an image.  The size that it prints out would be dependent on the resolution and your printer.

That's not true.

The physical size of the image is a function of the DPI setting (number of pixels/inch) and the number of pixels on the X and Y dimensions.

Modern file formats such as PNG and TIFF have a DPI attribute which can be set using image processing software such as The Gimp. For example, if I have a 100x100 pixel image with a resolution of 100DPI, it should be 1" square when printed at the correct resolution, if the resolution is then set to 50DPI it will be twice the size but it will look worse.

For some reason Eagle isn't scaling the image correctly so a 2.6" board is being skewed to 2.62" by 2.61", although this won't be a problem 99% of the time, there's always going to be that 1% of the time when it is.

Attached is a screen shot of my PCB in the Gimp showing the scale function, after I've scaled it to the correct size. Notice the pixels/inch setting is 300, the image size is 2.6" by 2.6" and the image is 780x780 (see title bar)? It's no coincidence that 780/300 = 2.6

The resolution of the printer is just the maximum resolution it can do and is not necessarily the resolution everything is printed at and the same is true for a scanner. The only problem with putting PNG images on the website is that some crappy imaging software ignores the resolution and tends to print at the screen resolution so I suggest that the user to import the file into a MS Word or OpenOffice, which honour the resolution setting and print form there. I don't know about web browsers, I suspect it varies but wouldn't be surprised if the screen resolution is used most of the time. I've also considered using SVG (Inkscape can convert PDF to SVG) but still isn't widely supported.

Not certain why you are exporting to a image. Print it directly and it's perfect.  I haven't used it, but you can print to PDF or PostScript as well if you really need to take it somewhere.

I export to a PNG to upload to a website. I could use PDF but Adobe has a nasty habit of scaling to fit the paper

Feel free to switch to Kicad or gEDA. The former is younger, but easier to use and with Windows binaries, it appears to develop quite fast. The latter is older (more features), but is not very easy to use, and doesn't distribute Windows binaries. Both are open source and have transparent (plain text) file formats.

I will certainly Kicad and will no doubt use it for most of my projects but I need to leard the proprietary software used by most companies too.

[alm]

For some reason Eagle isn't scaling the image correctly so a 2.6" board is being skewed to 2.62" by 2.61", although this won't be a problem 99% of the time, there's always going to be that 1% of the time when it is.

Scaling can be quite critical for PCBs, especially with fine pitch components with many pads. It sounds like rounding error, but it does sound unusual for a CAD package.

The resolution of the printer is just the maximum resolution it can do and is not necessarily the resolution everything is printed at and the same is true for a scanner.

Which is why it's confusing to mix ppi, dpi and spi, even though almost everyone does it (including Adobe). The printer resolution in dpi has very little to do with the number of pixels per inch (ppi).

I export to a PNG to upload to a website. I could use PDF but Adobe has a nasty habit of scaling to fit the paper

I would trust PDF scaling (assuming you turn of the 'fit to paper size' option) more than PNG, and I certainly wouldn't trust a word processor on exact scaling, it's not professional DTP software.

I will certainly Kicad and will no doubt use it for most of my projects but I need to leard the proprietary software used by most companies too.

No argument that most companies use proprietary software, but does Eagle really have any significant market share in the professional world? Most seem to use use something like Allegro, Altium or Pads, or even Orcad, but I very rarely hear Eagle mentioned outside the hobbyist scene (although I by no means have a complete overview of the EDA market).

[Zero999]

Thanks for that, I didn't know there was a difference and had to Google it.
http://www.pixelcg.com/blog/?p=174

I know that OpenOffice scales it correctly but I don't know about Word, I don't have it and I shoudln't have assumed it does it correctly.

Attached is a PCB I've exported to PNG, negatived and scaled so it's suitable for toner transfer. The resolution is 300ppi 780x780 so it should to be 2.6" when printed correctly. A quick way to test your word processor scales correctly, without printing it, is to import it to a blank document and measure its size with the on screen ruler. There also might be an option to view the picture size, I don't know about Word but OpenOffice certainly does, see attached, the dimensions are 6.6cm which is 2.6" and the ruler is correct too, the paper size is A4.

A more complicated method is to measure is size on the screen relative to the size of the paper, for example A4 is 210mm wide, the PCB is 2.6" or 66mm which is  66/210 = 0.32 of the paper size, so if the paper measures 100mm wide on the screen, the imported image should be 32mm, if it's noticeably different your word processor isn't scaling correctly.

When I put the circuit on a website, I'll include a PDF copy and a brief tutorial on how to disable the fit size to paper option in Adobe.

[TheDirty]

Let's put it to the test.

I had no problem opening editing and resaving this, but I believe the problem came with boards that were outside the limits of the FreeWare version.

[Simon]

just downloaded Kicad, not too bad, libraries are a bit naff, it looks like a nice designed software than expressPCB that I have sworn by so far but still in it's childhood stages of a fully equiped program ?

Does anyone use it and can advise me ? does it link the schematic to the PCB so that one can see connections between the parts to make manual routing easier ?