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Author Topic: from circuit to pcb  (Read 2924 times)

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lefteris_

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from circuit to pcb
« on: April 07, 2013, 18:12:22 PM »
Hello!!

It is the first time that im making a pcb with eagle and i want your help!

Basicly i have finished the pcb layout and i just want you to tell me if everything is ok!

I have exported an image of the board but i believe that i have place all the
componets too close to each other on the board!

I believe that the board can be better!!
(how i can upload an image?????)
I can also provide you with the board file on eagle.

_pike

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Re: from circuit to pcb
« Reply #1 on: April 07, 2013, 20:21:57 PM »
Hi lefteris and welcome to the forum.If you want to upload an image below the text editor it says
->" Attachments and other options" click on it
then on the attach tab press "Αναζητηση"
and then look in your pc for the image you want to upload.
Please make it with a max limitation of 2mb to avoid uploading problems

Regards Panagiotis

p.s also provide the schematic
« Last Edit: April 07, 2013, 20:24:31 PM by _pike »

lefteris_

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Re: from circuit to pcb
« Reply #2 on: April 07, 2013, 20:32:53 PM »
here are the file!
the board the schematic and the image of the board!

kam

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Re: from circuit to pcb
« Reply #3 on: April 08, 2013, 07:58:41 AM »
Welcome Lefteri,

first, there is always a better way to make a pcb. Your pcb is good except of 3 points: You could use bigger pads for the 18-pin dip in the middle, same for the 2 holes on the left side near the 8-pin dip, and bottom left there is a track very close to the batt+ and batt-

lefteris_

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Re: from circuit to pcb
« Reply #4 on: April 08, 2013, 18:52:39 PM »
how i can change the pads?Do i have to replace that component with another one with bigger pads?
Are the design rules ok?
Here is the circuit with the track moved!

George

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Re: from circuit to pcb
« Reply #5 on: April 09, 2013, 00:55:33 AM »
One thing everyone forgets on their first PCB, add some mounting holes so that you can screw it down (find out what you are going to mount it to or in first, and make the PCB and mounting holes to suit)

circuitfella11

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Re: from circuit to pcb
« Reply #6 on: May 08, 2013, 14:30:07 PM »
how i can change the pads?Do i have to replace that component with another one with bigger pads?
Are the design rules ok?
Here is the circuit with the track moved!

addition to pointers in making the pcb design is removing sharp 90 degree angles. you can make each corner as 45 degree. this method is good when you are using liquid to melt out the pcb metal, it looks cooler too.. ;)

but if u use fabricator for the pcb, neglect this... ;D

sirma

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Re: from circuit to pcb
« Reply #7 on: June 24, 2013, 00:23:34 AM »
You can design the pads yourself and you can also replace the component with the one having same dimensions with bigger pads. You?€™ll get the same result either way. Secondly, you only need to remove the sharp bends if your PCB has high-speed communication or signals which can get reflected or power may get lost because of the sharp bend. Rest of the observations are exactly as Kam mentioned.

printed circuits assembly
« Last Edit: September 08, 2015, 18:39:35 PM by sirma »

Sir N

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Re: from circuit to pcb
« Reply #8 on: July 01, 2013, 13:23:15 PM »
Hi,

how i can change the pads?Do i have to replace that component with another one with bigger pads?
In Eagle, go to Tools->DRC and on the 6th. tab (Restring), you can change the minimum parameters for eg. the bottom pad.


Are the design rules ok?
Unfortunately not.
You have grounded one side of the crystal for starters, so it would never oscillate.

A couple of questions to start you off:
Why use a dinosaur PIC?
Why use an even older BU chip?
There're newer and better versions of both.

Why route the traces on the top side (component side)?

Why use single pins for your connectors?
Take eg. a 7 row header for the segments and a 4 row header for each digit (or an 11..12 row header for both). it will be so much easier to solder in place.

Why no capacitors on neither the voltage regulator nor on the PIC?
Won't work without them.

You also need base resistors on the transistors, as well as on each segment line.

Let's keep it at that for now, I bet it's a bit to take in :)


The best way to handle it, would be to concentrate on the schematic at first. Get that reviewed and bash it around, until you get it in shape and then (first then), go to making the board. There is a lot to take in with any CAD system, so small steps takes you further than attempting  to run.

Further, with a first PCB, don't keep small size a priority. Make it larger, so there's room for correcting bloopers and so that you have an easier perspective on it all. When all is in shape, it's time to see if you can shrink it, without breaking any rules (too much ;)).

Another thing to notice is your trace width!
There's a lot of professional PCB makers that won't even be able to handle 8 mil narrow tracks and you'll certainly not be able to make it yourself, as even the tiniest speck of dirt will be able to cut the traces. I'd keep traces to a minimum of 24 mil or wider, especially on a first PCB - I usually trace 50 mil, whereever I can find room for it (wider on supply tracks with any kind of power handling needs).


All  the above aside, you did a fine first attempt, so don't get depressed over not getting every bit OK - we have all been in your position at one time or another (unfortunately way before the www in my case, so had to work it out myself the hard way) ;D