How-To: Design your own iPod super dock (Part 3)

We're back again with our continuing iPod super dock how-to series (see parts one and two, if you need to catch up). Last week we layed out the schematic for the board, and today we'll do a check up on the schematic, and design the PC board that we'll make for our super dock. We're getting close now, can you smell it? It's solder.

Before we get started, you might want to download our latest bundle of project files. Inside the zip file you'll find a copy of the connector library and the complete schematic we made last week.

Before we make the board, we'll double check for any wiring problems on the schematic. Clicking on Tools then Erc checks the schematic for electrical problems.

In this case, we're not using the T1 or R1 pins on the MAX232. The two power errors are because we didn't follow the EAGLE power and ground conventions. Again, no big deal. If you have any "nets" that aren't fully connected, you'll get warnings about them here. Even with our "errors" we're good to go.

To create the board, click the not so obvious 'board' button next to the drop down in the tool bar.

EAGLE will as you if you want to create the board from the schematic. Click Yes.

The new window will be black, with the various components sitting to the side. The white outline represents the actual PC board. Everything in this view is movable. If you make a mistake, remember that in EAGLE alt-backspace is undo. You get several undo steps, so feel free to mess around.

Drag the dock connector over to the edge of the board and place it. This is where the nice outline of the connector we created comes in handy. The yellow lines represent the connections that will be made to all the other components from the schematic.

Don't worry if you get this error. In the board view, it just means you tried to move or rotate a part off the board outline. Try it again placing it within the outline of the board. Alternatively, you can make the board really, really big and shrink it down later.

Play with the board layout until you get something you're happy with. We put all of the AV connections on one edge and the data connectors on the opposite. Take your time. Keep in mind that each yellow line will eventually become a trace. Life's easier if you remember the Ghost-Busters motto: Don't cross the streams.

In case you're wondering where the power connector is, we plan to use a spare firewire cable along with our iPod wall charger. That way we can't accidentally inject extra juice to our computer's FireWire ports.

Once you're happy, click Tools and Auto to pull up the options for routing the board. The auto router is one of the fantastic features of EAGLE. The software will play connect the dots to achieve a reasonably efficient trace layout. If it doesn't completely succeed the first time, don't worry. Keep reading.

To get the board to route completely, we had to take the grid to 15 mil. This is pretty fine, but we'll tweak the routing once the computer takes a shot at it. The option to set this pops up when the Auto command is used.

This is a slightly modified auto generated layout. At this point we'd made just a few changes. If you're curious, the fatter traces are replacements. We used them where they'd fit, and they'll be easier to etch later on. Red denotes top layer traces, blue the bottom.

A few tips on tweaking traces: With a trace selected, clicking the middle mouse button will change the layer that the trace lives on. To keep the signal, you'll need "via." Sometimes EAGLE will add them, but you may need to do it by hand.

Here we've moved all the through hole connections (but one) to the bottom layer for ease of construction. Laying out a nice PC board is really an art. This is our result after a few hours of tweaking until we were pretty happy. We made loads changes to the computer generated board. Don't be surprised if the ultimate version ends up a bit different.

Next time we'll bring all the pieces together and finish our super dock. The traces on our board are pretty fine for the usual home PC board making techniques; we'll test out a few and let you know what gives the best results for making your own. See you next week!

[heyhow @ May 2nd 2006 1:36PM]

Woohoo!!

[eskimo @ May 2nd 2006 3:07PM]

So does this mean we'll be seeing a contest on the best iPod dock sometime soon?

[Chad @ May 2nd 2006 3:27PM]

I'm just hoping that this printed board will be available for purchase! I can do the soldering, but have no idea on printing boards!

[bob @ May 2nd 2006 3:39PM]

http://www.radioshack.com/product/index.jsp?productId=2103234&cp=&pg=2&origkw=rca+phono+jack&kw=rca+phono+jack&parentPage=search
i was wondering if this would work for the project
btw great project its awesome

[joe @ May 2nd 2006 4:11PM]

i've been following these steps and have actually pretty much finished what was shown this week. i plan to mount mine inside an altoids can. i've been looking for resistors from mouser. from collective online research, i need a 1k resistor to let it know its a dock and two 10k resistors to make the ipod charge even if its not on. does anybody know what wattage these resistors need to be because mouser offers several different wattage ratings and i want to be sure i have the right ones. i got the resistor information from http://ipodlinux.org/dock_connector

hopefully somebody knows or they will tell next week. if you want to make your own circuit boards im going to use the instructions from http://www.fullnet.com/u/tomg/gooteepc.htm

thanks, and awsome series!

[sven @ May 2nd 2006 5:40PM]

thanks for this nice guide.
there something i'd like to add. one of the first rules of routing is: don't make 90� corners!

[howhow @ May 2nd 2006 8:01PM]

Hey, is the last part going to be soldering everything on the board? Arent u guys going to make a nice little enclosure for it or something? The enclosure was pretty much the only reason i kept reading these.

[mackit @ May 2nd 2006 11:13PM]

Hi get info but I cant down load the eagle program Im using a MAC!!!
is there a mac version

Cheers
peter (new zealand)

[Timmay @ May 3rd 2006 8:20AM]

This is pretty cool, i'm going to try to replicate this and then try to build a similar ultra cradle for a Palm Connector (the new treo/tx/lifedrive connector).

Timmay

[Nate MC @ May 3rd 2006 9:02PM]

I'm with Chad on this one, have solder will travel but I've never done a board etching although this could be the time to learn.

I saw the begninners board etching kit at Radio Shack the other day and wondered if it would work for this project. It's only $15 and probably has enough stuff to make a few of these.

[dave @ May 4th 2006 3:36AM]

just out of a matter of interest, why cant you have 90 degree angles when routing? i remember from working with microwave transmitters that with such high frequency waves, angles can cause problems, but why on pcbs?

thanks

[Ridax @ May 6th 2006 1:30AM]

#6: You can use any kind of resistor wattage. 1/8W or 1/4W is enough so no need for anything fancy.

[Duncan @ May 22nd 2006 10:52PM]

Where can I get the MAX232 and capacitors?

[Will O'Brien @ May 22nd 2006 10:55PM]

You can get chip samples from maxim or get both from somewhere like mouser electronics or digikey. Both should normally carry them.

[Scott @ Sep 19th 2006 1:31PM]

Im kind of fustrated here because the project files link no longer works and ive emailed Engadge with no replies... kidna sucks... can some one like relink it?