eagle cad pcb help

[aruna1]

Hi I designed and routed a custom PIC board based on 18F452.
before printing on a transparent sheet i printed it on a A4 sheet,but distance between pins are smaller than actual size of the PIC.that is i cant place 18F452 on pads of footprint,foot print is smaller than actual 18F452.
since i don't have a printer i first printed it with adobe printer to a pdf file and then printed it to a paper at my friends place,i didn't do any resizing on pdf file.i just printed it with actual size.
can someone help me with this?
i have attached all relevant files here

[Cristi_Neagu]

Hi.

What i reccomend is the way AutoCAD calibrates plotters.

Start a board layout and draw a rectangle. Remember the width and length of the rectangle. Next do what you always do: print the layout (that is to say the rectangle) to a pdf, then go to your friend's and print the pdf.

Remember that if you plan to print the layout to a A4 sheet, you need to tell EagleCAD that you will be using a A4 sheet when printing to pdf. Also, set sheet size to A4 in the pdf printer's options.

After you get the A4 print, measure the width and length of the rectangle. Let's say that you drew a 5x8in rectangle in EagleCAD, and on the A4 sheet you have a 5.1x7.9in rectangle. You do this:

On x direction (if you hold the piece of paper in front of you, X is horizontal):

5in--------5.1in     (if i put in 5in and i get 5.1, then how many inches to i need to put in to get 1in?)
xin---------1in      (don't ask...it works.)
        x=5*1/5.1=0.98   <-remeber this number

and on the y direction:

8in--------7.9in
xin---------1in
        x=8*1/7.9=1.012 <-remeber this as well

Now you go EagleCAD, in the board you are working on, click file->print setup, and you enter those two numbers in the calibrate zone (bottom left of the window): you put 0.98 for X and 1.012 for Y. Now you should print another test rectangle, just to make sure.

Also, remeber to turn off any kind of fiiting aide that messes up with the scale. Adobe Reader does that. On the left side, some way down, under "page handling", set "page scaling" to "none"

Now all your EagleCAD prints should be on a scale of 1:1... in theory.

P.S. If you get a bigger rectangle, and after the calibration it gets even bigger, then that means i messed up. Just reverse the formulas above and all should be well (insted of 5/5.1 do 5.1/5).

Good luck.

[Soeren]

Hi,

P.S. If you get a bigger rectangle, and after the calibration it gets even bigger, then that means i messed up.

Sounds right to me

Would perhaps be easier to set the grid to 1mm (or smaller) - if A4 is used, there's a good chance the user is more accustomed to the metric system).

Here's a rectangle 100.00mm x 50.00mm rectangle to make calcs a little easier, but still being able to differentiate the two directions.

[Cristi_Neagu]

if A4 is used, there's a good chance the user is more accustomed to the metric system).

I use EagleCAD with a grid of 0.1in even tough i use metric every day of my life, because it's easier to think spacing in terms of 0.1, 0.2, 0.3... than 2.54, 5.08, 7.62... But that's me. In hindsight, yes, i should have assumed he might use either system of measurement or that he might use some other grid size altogether. Thanks for the correction

[Soeren]

hI,

I use EagleCAD with a grid of 0.1in even tough i use metric every day of my life, because it's easier to think spacing in terms of 0.1, 0.2, 0.3... than 2.54, 5.08, 7.62... But that's me. In hindsight, yes, i should have assumed he might use either system of measurement or that he might use some other grid size altogether. Thanks for the correction

Me too, but this was for calculating the precise difference when adjusting (yes it can be done in imperical as well, but using percentages all the time, 0..100 is close to counting fingers - just for the record, I only have 10% of that, luckily not all thumbs ).

I usually go to metric when I eg. measure a component with a digital caliper and make a foot print for it (if it's not in 0.1" modulus), as I am more used to thinking in metric, but I hate it when some script make a board go to metric, while I'm in the middle of a layout (Gee, 6 units of 1.27mm is... Damn, back to imperical ).

I would guess, that even if you're used to imperical units, calculating percentages would make 0..100 a daily commodity as well?

[aruna1]

I will try it 

[Cristi_Neagu]

All i can say, Soeren, is that you definitely have more EagleCAD experience than i do
Also, if i am not mistaking (and i don't believe i am http://www.google.ro/search?client=opera&rls=en&q=imperical+units&sourceid=opera&ie=utf-8&oe=utf-8 ), its imperial units... But i've been known to "split the hair", so to speak...

Also, aruna, let us know how it works

All the best and good luck

[Soeren]

Hi,

Also, if i am not mistaking, its imperial units... But i've been known to "split the hair", so to speak...

You're right of course, that's what sometimes happens when you post while you should be sleeping   I must have got it mixed with "emperical" (yeah, I'm a big fan of good old Immanuel and all of his friends ).
Sorry... Will go to bed now, promise 

[aruna1]

hmm,I guess i have to wait few more days before test this as my friend has visited his relations in another city