Summary

I wanted a holder that I didn't have to peel the silicon cover off the phone all the time to use. The aftermarket clamp types were chunky and ugly. I also wanted to charge the phone without manually plugging in a cable.

Instructions

The holder is made to accept a Samsung Nexus or Galaxy2 with the soft silicon sleeves that are available for them.

Once printed, you have the option of purchasing a micro USB car charging cable for it. Insert the micro USB cable through the square hole at the base and slide the phone down to meet it and then push the phone all the way till it seats. Carefully then spot some super glue around the micro USB plug and the square hole to locate it in the correct position. Once dry, carefully withdraw the phone. You can now add more glue or carefully fill any void with silastic or aradite or something that locates the plug permanently. Sliding the phone in should now line it up to meet the micro USB plug every time.

The four holes on the flat back of the holder are for a cheap Samsung car holder I purchased off eBay. It has a suction cup for the windsceen, or alternatively a vent mount. They are about $14. The part that meets my phone holder is a rectangle with four tangs that fit into the back of my holder, and pushed sideways to lock in very positively.
The larger recess and thin channel in the back are for a antenna coil I also found on eBay. Its postioned up against the back of the phone and allows it to use an exterior car antenna. The channel allows the cable to exit from under the mount.

The photos show my natural colour prototype - the finished item is in black. The photos show the aftermarket clip for the back as well. I discarded the glass suction cap part and made a small mount that slides over my old Nokia mount already in the car. The aftermarket part is adjustable for angle and rotation (height). Once you have the mounting plate that clips to my holder, you can make whatever mounting arrangement you like, or use it as purchased off the windscreen or vent - up to you.

Finally, the finished file has a recess for your thumb to help slide the phone out of the holder which is not shown in the prototype photos.

Samsung Nexus/Galaxy phone holder with cover and exterior antenna..