Here is a tap I created for the Raspberry Pi to allow access to the header pins even though it may be blocked by a “Pi Plate” / Shield that is using the header without pass-through pinheaders.
The Pi side of the PCB uses a trick from SparkFun for creating better contact with pins: spacing opposing pins 5 mil in opposite directions to allow the PCB to hold the header tightly.
These were created in the gEDA Suite’s PCB program. Each .zip file contains the .pcb file, a photo mode export of the board (.png) and a zip file of gerbers, suitable for upload to OSHPark, Seeed Studio, ITead, etc.
These files are released under the CC BY-SA 2.5 Canada license.
Please note these designs are as yet untested. Use at your own risk.