Circuit design(other than eagle cad)...

I would like to edit the Pico arduino shield so I can add other components onto the shield, however I don't have eagle cad.

Will the eagle cad board and schematic files open in any other free circuit cad program?

I think Altium Circuit Maker lets you import eagle files.

@d0773d There is another great tool KiCAD (open source)
And there are some tools out there to convert Eagle to KiCAD files.

however I don't have eagle cad.

Can't you just install it? It's free for personal use.

But as @Jorgen says, there are some conversion tools. Luckily the file format is human readable XML so it's not that hard for people to write converters

@the1laz I downloaded and installed Altium Circuit Maker and your right, it supports eagle files. The downside to Altium Circuit Maker is it's community driven and requires internet access to work on your project :-/

@Jorgen I downloaded and installed KiCad, but I have yet to figure out how to install https://github.com/DanChianucci/Eagle2Ki­cad apparently I don't have Tkinter installed for python. I'm still stuck on the installation process of Tkinter.

@Gordon I wasn't aware Eagle was free for personal use and was under the impression due to the license changes that there was a small fee for the "light version". However, I was wrong and installed eagle.

Eagle Cad seems to be the easiest approach, for me atleast :-)

@d0773d Good to hear that you've got something working. I use eagle for my boards, only because that's what I started with and I'm happy with it. There's a lot of debate about which free/cheapish pcb cad program is the best, but what I like about eagle is that it seems to be the more widely supported one in terms of libraries and open source schematics.

I also like eagle. But I currently working on KiCAD, because a friend of mine is one of the guy working on that open source tool - and I do some kind of testing on OS X ;)
But you are right, it is not as easy to get eagle files to KiCAD. Hopefully the KiCAD guys make this much easier in near future.

@the1laz Ya, I'm noticing the popularity with using Eaglecad and I did notice the plethora of libraries and open source schematics available.

Eagle cad is bit of a learning curve for me. I still can't figure out how to add two 3 position headers at 17.78 MM apart.

@d0773d yes, it's all a bit rough around the edges - but then it seems most of these tools are.

For the header, you could:

• drag out a dimension line to the length you want, then drag the header along to match that.
  
• Set the grid to exactly 17.78mm, the ctrl-click (it should then position the item actually on a grid point), and then drag it off one grid point
  
• Save the .brd file, open it in a text editor, find the reference to your component and just add 17.78 to the position :)
  
  

I need to look at KiCAD more, it seems good - just whenever I need to do something quickly (which it seems I always do) I tend to come back to Eagle because it's what I know.

I think learning and using other packages than Eagle is a good idea. I feel there's is much more similarities between the other I've tried than Eagle has with any of them. With KiCAD f.ex you're learning to use EE CAD in terms of navigation and UI (KiCAD has a slightly weird way to do symbol-to-footprint but every package has it's quirks).

I will convert my open source projects to Altium Circuit Maker as I really like the way it feels (though KiCAD is more productive due to the fact I know, and there is, shortkeys).

I've found Altium to be a bit slow and finding parts is a learning curve. Also, no Linux, which isn't too bad but I've been using it for all my programming lately. It is interesting how the parts tie into actual part numbers and pricing though. I might just need to get used to it. Unfortunately, most CAD programs seem to have awkward learning curves and controls, regardless of whether they're for pcbs, modelling, CNC, etc.

Thanks to @user66772, there's now a KiCad part for the Espruino Pico, available on the Espruino GitHub page