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Topic: Aproaching definitive PCB (Read 1 time) previous topic - next topic

Pancra85

First of all it's the first time I am doing a complex project with Arduino and also with any electronics.

For the past months I have been working on some sort of synth with an AY-3-8910 chip.
I have finished with almost all of the Arduino programing and did a schematic with Eagle for taking the next step, creating a PCB and soldering the components for a definitive installation.
From the attached image you can see that the circuit is somewhat complex and after designing the actual board (2nd image) everything fits in a 12x12 cms square (4.8x4.8 inches)

Now, using Eagle autorouter it's imposible to do all the connections on a single layer, so I have to use two (up and bottom). That increments the difficult of printing and etching.

I tried printing both layers with the toner method (using a magazine paper) but I failed because I couldn't align both layers correctly, I think it's because it was difficult to do with magazine paper. After doing the holes with a manual drill and a 1mm drill bit I noticed that the component holes where off from the actual printed place.

What would you recommend me to do? Should I try again with photographic paper? Do you think it would be better separate it to different single layer modules and connecting them with cables?

What do you think?

Thanks!!!

oric_dan

I would create Gerber files, and send them off to one of the pcb houses
to get the boards made professionally.

Pancra85

I thought about that, there are 2 inconveniences.

1) I live in Argentina so I would have to wait like 2 months for it to get to me.
2) I may have some errors on the design so everything will be wasted if I can't correct them. That's why I wanted to make this by myself first, in order to test it.

I may try consulting some prices with China companies, the shipping to here is cheaper from China.

Also, by ordering one alone I think the price will be high, right?

Osgeld

#3
Sep 23, 2012, 12:52 am Last Edit: Sep 23, 2012, 12:53 am by Osgeld Reason: 1
A good way to help line them up is make reference points on the outside of the board (like one on 2 opposite corners), once you have one side, drill tiny holes in them and poke a pin though them, now when you go to put the other side on you can poke though the paper on your reference marks

it wont be perfect, but its better than trying to eyeball it

two other things to keep in mind is that autorouting is pretty dumb, and sometimes just moving something or rotating it will give you what you need

Quote
Also, by ordering one alone I think the price will be high, right?


I doubt you will find a house with a minimum order of one, and it adds up real quick

a.d

I would try without using the autorouter - it seems like it will be hard or it will take a long time, but its worth it.

I find that doing the power first helps, and if I have the top layer for mostly going horizontal and the bottom layer vertical things get a bit easier. You could of course swap those around.

This might help you condense your board into a smaller area so you can get it into one of seeed studio's 10cmx10cm board pricing ranges - which is a lot cheaper than their 15cmx15cm price!

One things am doing at the moment is splitting up component parts of a circuit over two boards to fit into the 100x80mm board size restriction in Eagle, then connecting the relevant parts and power with a double row pin header.

One last thing, and its not important but it bugs me, odd angle traces look ugly.

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