To use FSR's with the smoothieboard an aux board is needed to interface the FSR's to the smoothieboard's endstop input. Smoothieware will accept this input as if it was a simple mechanical switch.
JohnSL (Github) has created such a board. It is available via AndOrNot, TriD Printing & UltiBots. See John's blog post about the board. This board is powered from the endstop pins. Also see AndOrNot's write up on FSR's design for a delta printer FSR pad design.
The Deltabot group is where most discussion on using FSR's is located.
Topics to look for are:
- Alternative boards like the arduino mini.
- WingWong's trinket derived design.
- Mounting of FSR's