Wow, never realized the art behind circuit traces

Wow, never realized the art behind circuit traces

Hans
Hans

October 20th, 2011, 10:11 pm #1

In an industrial sense that is.

I've been doing some circuit boards both as a hobby, and to make a couple bucks on the side. When you get down to it, doing these things manually sure takes a different mode of thinking. That, and there's a lot of room for expression in them too.

But man, tying together a 40pin, a 28pin and a 14 pin socket into a 2" by 2" space is an interesting challenge.

-Hans
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Levi
Levi

October 21st, 2011, 1:07 am #2

i don't think i can post up pics of my work (NDA, business and all that) but its very much the same pain as yours.

What CAD software are you using? 2 layer? 4 layer? what kinda goodies are on it? who do you get um made through? and any other nifty info you wana share?

as for my work, were stuffing a 44pin CPU, 2Gb of flash ram, accelerometer, gyroscope, charging circuit, DC-DC step down converter, USB, and 3mm LED, all onto a single sided (for thicknes reasons) 27mm by 23mm 4 layer PCB.... pretty much having to push min. distance tween everything, everywhere. nothing could be auto routed....


I understand the mind set you speak of. I would make some stupid routing choices every morning, but by the end of the day id be in the "zone" and fix um up!

almost more art then science alot of times!

post up pic's of the work if you can! i would love to see it!


-Levi
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Hans
Hans

October 21st, 2011, 2:20 am #3

Right now I'm still plugging along with ExpressPCB, with the drawback of having to go through them for the boards. I find the software quick and easy to use, particularly when building up oddball components, but no auto-router on it which would be nice. I keep seeing guys rave about Eagle, but I just can't justify the cost for the amount of work I do. Tried FreePCB, but found it very clunky. Building components was particularly tiring, and almost nothing I needed was in the library.

Just two layer stuff right now. Everything I do is thru-hole, which is pretty greedy on real-estate, so no need to go with four layers yet. Everything I do is dealing with pinball machines right now, so that means mostly older components such as 6800 series processors and 7400 series logic chips. That, and since I hand assemble it all, I can't see going with SMD stuff just yet. Maybe in the future though.

Nothing impressive to show just yet, the only boards I've actually had made were nothing but a couple of 10-LED bar strips on them to use as a banked test light rig. But this EPROM adapter is definitely pushing up the complexity a lot for sure, once I get it done I'll get some photos up of it.

-Hans



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attic rat
attic rat

October 21st, 2011, 4:34 am #4

Back in the day, circuit boards had ONE layer. And you etched the copper with chemicals.
Well, at least you don't have to deal with wire-wrap design. Ampex did that for a while. Evil stuff... EVIL.
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Levi
Levi

October 21st, 2011, 4:52 am #5

Right now I'm still plugging along with ExpressPCB, with the drawback of having to go through them for the boards. I find the software quick and easy to use, particularly when building up oddball components, but no auto-router on it which would be nice. I keep seeing guys rave about Eagle, but I just can't justify the cost for the amount of work I do. Tried FreePCB, but found it very clunky. Building components was particularly tiring, and almost nothing I needed was in the library.

Just two layer stuff right now. Everything I do is thru-hole, which is pretty greedy on real-estate, so no need to go with four layers yet. Everything I do is dealing with pinball machines right now, so that means mostly older components such as 6800 series processors and 7400 series logic chips. That, and since I hand assemble it all, I can't see going with SMD stuff just yet. Maybe in the future though.

Nothing impressive to show just yet, the only boards I've actually had made were nothing but a couple of 10-LED bar strips on them to use as a banked test light rig. But this EPROM adapter is definitely pushing up the complexity a lot for sure, once I get it done I'll get some photos up of it.

-Hans


Very cool stuff none the less! i find most all circuit stuff pretty cool! "noob" or "pro"

there is a free copy of eagle, and also a demo. limits you on size and to 2 layers. but i think it has some auto routing.... so you can still give it a go.

this will be my first SMD build... TSOP, QFN/DFN and all the way down to 0201 sized resistors/caps.... all by hand.... ill let you know how it goes! Ive read that its not as bad as one will think...

how much 7400 series chips are you using? and have you thought of using a programmable replacement of some sort? just to drive the chip count down?

what kind of a com protocol does the eprom to CPU use?

hurry up and get stuff done! i want to see some pics :D

-Levi

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Robin Bobcat
Robin Bobcat

October 21st, 2011, 7:13 am #6

Back in the day, circuit boards had ONE layer. And you etched the copper with chemicals.
Well, at least you don't have to deal with wire-wrap design. Ampex did that for a while. Evil stuff... EVIL.
Uphill! Both ways! In the snow! With rabid wolves nipping at your hand while you tried to make solder connections!

I actually had a CAD course where one of the projects was to design circuit traces - we really didn't need to know what the components were, or have any sort of 'tuned' circuit, they just needed to know we could draw the symbols correctly.
Rotten bastard that he was, the teacher included an 'extra credit' assignment that was physically impossible in two dimensions. Of course, this was to teach that 'sometimes you need to tell the engineers they're wrong', blah blah.
Me, I just added a notation for two extra jumper wires.
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Joined: April 18th, 2005, 4:54 pm

October 21st, 2011, 6:05 pm #7

Very cool stuff none the less! i find most all circuit stuff pretty cool! "noob" or "pro"

there is a free copy of eagle, and also a demo. limits you on size and to 2 layers. but i think it has some auto routing.... so you can still give it a go.

this will be my first SMD build... TSOP, QFN/DFN and all the way down to 0201 sized resistors/caps.... all by hand.... ill let you know how it goes! Ive read that its not as bad as one will think...

how much 7400 series chips are you using? and have you thought of using a programmable replacement of some sort? just to drive the chip count down?

what kind of a com protocol does the eprom to CPU use?

hurry up and get stuff done! i want to see some pics :D

-Levi
I'm dealing with an old pinball machine that had three 2Kx8 EPROMS and three 512x8 PROMS on it, of which the proms are totally unavailable... as are anything compatible with them.

So, I figured I can squeeze all the code onto a single 8Kx8 EPROM by making a small piggyback board that goes into the CPU socket. The daughter board will hold the CPU, a 2764 EPROM and a single 74LS20 for the chip select circuit. I managed to get them all on a 2.5"x1.9" board. 6800 series processors are parallel on the data and address bus, so it's straight pin to pin on 8 data lines and 13 address lines for this EPROM.

Since I had a little bit of space to spare, I put indicator LED's in there for the +5v and the Reset circuits too.

My little tester boards are absurdly simple, but here's what they look like
http://www.siegecraft.us/tester.html


-Hans
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jkeyser14
jkeyser14

October 21st, 2011, 6:20 pm #8

In an industrial sense that is.

I've been doing some circuit boards both as a hobby, and to make a couple bucks on the side. When you get down to it, doing these things manually sure takes a different mode of thinking. That, and there's a lot of room for expression in them too.

But man, tying together a 40pin, a 28pin and a 14 pin socket into a 2" by 2" space is an interesting challenge.

-Hans
We just got done creating a product at my work where the pcb design and layout for the PCB boards was 7 months of an electrical engineer's time and another month of my time dealing with the mechanical aspects (critical component placement, thermal management, tolerance analysis, etc). The boards were 14 layers each, 3 oz copper traces, the works. Two of the boards had over 600 through holes for connectors in a very small footprint.

If I was doing the layout I would have went insane. The shear number of traces, the layers, etc was mind numbing. In terms of size and complexity I would equate the project to designing 3 different computer motherboards, except that computer motherboards don't also have to handle RF signals.
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Wojtek
Wojtek

October 21st, 2011, 6:40 pm #9

Right now I'm still plugging along with ExpressPCB, with the drawback of having to go through them for the boards. I find the software quick and easy to use, particularly when building up oddball components, but no auto-router on it which would be nice. I keep seeing guys rave about Eagle, but I just can't justify the cost for the amount of work I do. Tried FreePCB, but found it very clunky. Building components was particularly tiring, and almost nothing I needed was in the library.

Just two layer stuff right now. Everything I do is thru-hole, which is pretty greedy on real-estate, so no need to go with four layers yet. Everything I do is dealing with pinball machines right now, so that means mostly older components such as 6800 series processors and 7400 series logic chips. That, and since I hand assemble it all, I can't see going with SMD stuff just yet. Maybe in the future though.

Nothing impressive to show just yet, the only boards I've actually had made were nothing but a couple of 10-LED bar strips on them to use as a banked test light rig. But this EPROM adapter is definitely pushing up the complexity a lot for sure, once I get it done I'll get some photos up of it.

-Hans


I've learned it while doing school projects, and now all "normal" apps are confusing me, because I'm used to Odd Eagle Ways. Wish I could afford the full version - the free one has crazy small work area.
Mind, I have no idea if it changed the interface after the 4.x that I know.
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Hans
Hans

October 21st, 2011, 10:05 pm #10

Uphill! Both ways! In the snow! With rabid wolves nipping at your hand while you tried to make solder connections!

I actually had a CAD course where one of the projects was to design circuit traces - we really didn't need to know what the components were, or have any sort of 'tuned' circuit, they just needed to know we could draw the symbols correctly.
Rotten bastard that he was, the teacher included an 'extra credit' assignment that was physically impossible in two dimensions. Of course, this was to teach that 'sometimes you need to tell the engineers they're wrong', blah blah.
Me, I just added a notation for two extra jumper wires.
I see how it works now. The Ship stays in place, and you just move everything else.

Sorry, Futurama moment there.

-Hans
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