This is a simple pen for the Vodafone 845 (Huawei v845/u8100) that plugs into the auido jack and curls around the edge.
It is not finished but worked, the curve needs a little more adjustment.
I do not use it anymore as the 3.5 audio plug caused problems (Caller did not hear me as the phone expected a microphone).
I did not want to use the USB plug instead as it looked more fragile. But you may can use this as a basic concept (for geocaching dirt protection or another phone)
The rounding needs to be adjusted a bit.
Print standing or laying, depending on your printer.