Nexus One Dock

I've seen a lot of discussion about paper clip and cardboard docks for the Nexus One.  Thought I would post what I made the other day and applicable files I used.

This process could be applied for any phone.

This dock does not yet have a power source or a docking 'sense' capability, but I hope to add some of this in the future.  And of course, I would like to produce a version that can take my phone with the protective case.

This part was made using a CNC router mill, the Zenbot.

Step 1: Measure the Phone

First effort overall will be to get a version of the phone into the computer where it can drive machining instructions.

Lacking a 3-D scanner, I have instead used a orthogonal cross section method to get close to the shape of the bottom of the phone.

Basically, I traced around the phone from the front and the side.  Using a 2D cad software, I inserted the picture and traced the line.  Now using a second 3D cad software, I place these two lines at 90° to each other.  Now, I have the framework to create a surface for the phone.

Step 2: Tweak the Surfaces

Next, the most daunting task.  The model needs to be tweaked until its correctly sized to the phone.

I'll take the model I developed, and use it to 'scoop' out from some stock to generate CNC code to cut the stock.  Then I'll see how it fits, correct, and retry.

It took about three tries to get the uncovered phone to fit, and another three to get the covered phone to fit.

Now that I have the phone bottom shape, I can focus on making the rest of the dock shape.

Step 3: Dock Design

Well, I wanted to go with something that is a little different than previously done.  I also wanted something that would require 2 sided machining with a 3 axis machine.

By angling the part in the stock, I can machine from a 2in thick part.  By machining from larger stock, I can flip the part over after machining one side to complete the other side.  This requires that a thin connection to the original stock be maintained on the sides.  This stock can be removed after the rest of the machining is done.

Note, the .igs file has the sized insert for the uncovered phone.

Step 4: Machining

Now its time to cut the piece.

Using MeshCAM, I produced two separate files, one for each side of the machining.  After the first is complete, I flip the part over and machine the other side.  Its very easy to produce complicated 3D forms with this software.  The main issue is, it is somewhat limited in the final surface finish because you can only do x and y travel contours.

I chose to do these practice pieces with high density foam.  Cuts very fast, and its easy to fix any tool travel errors.  Easy to sand afterwards.

After sanding, I applied a coat of foam safe epoxy to strengthen.

Step 5: Next Steps

I made one piece using laminated MDF, but really it isn't much stronger than the foam for structure.

I may use the foam version in a sand casting into aluminum.  Or I might try my hand at aluminum machining.  A hardwood is also a good option.

Eventually I'll look towards adding a charging option, ideally with the pin connections on the bottom, but if need be, a micro usb connection.