Eagle PCB design question

[Drools]

Sorry to be a pain by having so many questions.
When I'm working in Eagle PCB layout, I find it very difficult to find the correct part to insert into the layout.
I usually search for a suitable part from DigiKey then try to find a matching part from the Eagle library that has the same foot-print as the DigiKey part. I find this very difficult and time consuming, is there an easier way to do this?

Thanks
Brent

[Jay C]

I have found the Sparkfun library has a lot more recent parts, but the best solution I found was to make my own library for parts I knew I would use more than once.

Jay

[Drools]

Thank you very much Jay, I downloaded the library and put it to good use.
I was wondering if you guys would mind proofing a board design for me.
I have not done a board of this complexity before and I do not want to waste PCB material making bad boards.
I had to rename the file to txt to upload it to the board. Just down and rename it to a brd file for Eagle to find it.

Thanks

[Jay C]

Wow, those inline parts are dinky, 0201 ... not gonna be hand assembling it then right? I don't know about others, but I don't like my wires to be that close to others. You's are .004" apart. Are you gonna mill this? If not, check with the board house and make sure you set your rule check to match their tolerances, trace widths, and standard drill sizes.

Why the vias to the top later under the long chip, why not leave it on the bottom?

Also, why did you move the dimension box to the bottom later? If you are going to use it for the milling, you need to move it to the milling layer (46) for PCB-Gcode to create the milling gcode.

Finally, what is it?

Jay

[Drools]

Good points Jay, I'm still learning.
I forgot the trace to the ground on pin 22 of the chip. I switched out the 0201 package for 0402, yes I was hoping to solder these by hand or make a reflow hotplate to do the job. I could space a little further apart, the traces going up the right hand side. I must have deleted the box outline by mistake, I'm a noob on Eagle. I wish I had a tool to drill the holes, I was supposed to get one but nothing materialized as of yet.
I still need to find or make a DC POWER JACK for the board. I need a R/A(right angle) Barrel type one that I can purchase from DigiKey and has a Eagle counterpart. I did some preliminary checking but did not find a Eagle library part that matched any of the Digikey parts. I have to check the total power requirements on the chips I'm using, I might just be able to run the board off USB power alone.
The circuit has already been running for a few weeks on my bread board at home, it is a replacement for a parallel port interface with some special code running on the uC.

[Jay C]

Originally Posted by Drools Good points Jay, I'm still learning. I forgot the trace to the ground on pin 22 of the chip. I switched out the 0201 package for 0402, yes I was hoping to solder these by hand or make a reflow hotplate to do the job.

Do you have any of these parts to see how truly small they are? Were you going to mill a solder mask or try to squirt some dabs from a syringe?
http://en.wikipedia.org/wiki/Surface-mount_technology
0201 (0603 metric) : 0.024" × 0.012" (0.6 mm × 0.3 mm)
0402 (1005 metric) : 0.04" × 0.02" (1.0 mm × 0.5 mm)

Keep in mind your traces are .016" and that's pretty small. Might be a better idea to scale up to 603 to start with.
http://nerdfever.com/wp-content/uplo...ch-o-meter.png

I could space a little further apart, the traces going up the right hand side. I must have deleted the box outline by mistake, I'm a noob on Eagle. I wish I had a tool to drill the holes, I was supposed to get one but nothing materialized as of yet.

I use the Wolfgang to drill holes. You just need the PCB bits. But you don't want to have to stock a bunch of different ones, and if you are going to be adding vias by hand, you don't need the holes any bigger than 30ga wireor whatever you decide to use.

I still need to find or make a DC POWER JACK for the board. I need a R/A(right angle) Barrel type one that I can purchase from DigiKey and has a Eagle counterpart. I did some preliminary checking but did not find a Eagle library part that matched any of the Digikey parts. I have to check the total power requirements on the chips I'm using, I might just be able to run the board off USB power alone.

http://www.sparkfun.com/commerce/pro...roducts_id=119 Making a part is easy. Just follow the sparkfun tutorial.

The circuit has already been running for a few weeks on my bread board at home, it is a replacement for a parallel port interface with some special code running on the uC.

Well, you can also try shrinking the signal lines to 12mils if you think your machine will do it. I try not to get the parallel wires any closer than 8mil worst case, and I do my best to keep them as far apart as I can.

[Drools]

Thanks again Jay, I took your advise and made some changes.

[Jay C]

I just realized you are creating the board from scratch without drawing a schematic. Keep in mind that the green through-hole pads will be on both sides. Thus the vias and jumpers you have are not needed, just run the wire on the top side from pad to pad.

I would highly recommend drawing the schematic first though. makes routing a lot easier.

Jay

Update: I removed some vias so you could see what I am saying. Vias are "expensive" both in your time and if you send to a board house.

[Jay C]

I did some rerouting. Do your signal wires need to be 24mil? Are they logic TTL or something more?

Also, anywhere the green pad overlaps a red or blue wire, they will be connected. You had some shorts due to this.

Jay

[Drools]

Sorry for the questions I'm just trying to learn the process and do the board correct the first time I route it. I always thought a via was to transfer a signal trace from one layer to an other layer. In my case top to bottom layer.
I did try to create the schematic and then make the board from there but there did not seem to be any logic to what the board layout was when I did the auto routing?
Jay, I notice the LED does not have any traces on the bottom and it is a through-hole component, how do I solder the LED if it is sitting flush to the PCB?
Edit:
I think I see now what you mean Jay, I do not need to switch the trace from layer to layer as much as I have been doing. The pads will be routed on the bottom anyway so I will have something to solder to.

I did have the logic traces at .016 but in your previous post I thought you meant that was too small so I bumped them up to the next size.

[Jay C]

Originally Posted by Drools Sorry for the questions I'm just trying to learn the process and do the board correct the first time I route it. I always thought a via was to transfer a signal trace from one layer to an other layer. In my case top to bottom layer. I did try to create the schematic and then make the board from there but there did not seem to be any logic to what the board layout was when I did the auto routing? Jay, I notice the LED does not have any traces on the bottom and it is a through-hole component, how do I solder the LED if it is sitting flush to the PCB? I did have the logic traces at .016 but in your previous post I thought you meant that was too small so I bumped them up to the next size.

No I meant the spacing between them seemed too small. I'm not sure which are LED's unless it's the 2 diodes by the Berg connector (might want to add component labels). Any green pads will show up on both the top and bottom layer. If you have a green pad existing that has the same signal you want to take to the other side you don't really need a via. But, if you are doing this at home, and you don't think you'll be able to add a little solder on both sides of a through-hole part then that might be a good idea ... just more work filling vias.

Some like the autorouter, I prefer to hand route. Have you ran PCB-Gcode and looked at the resulting gcode. Have you been over to www.millpcbs.com and looked through Phil's suggestions/methods?

I would want to send me your circuit schematic, I could try my hand at routing it.

Jay