I have the software working for Fans, Bed, Extruder, Steppers, Endstops, thermisters. In short everything I need to use the board. I have not yet tested Auto level or filament sensor. All functions working on the LCD. Will go through a print on the bench, will exercise all steppers, heaters and the fan. The PID functions nicely on both heaters. To do: Auto level and filament sensor. I modified the Ramps board: remove D1, move the 5amp PTC into the 11 amp PTC position and replace the 5amp PTC with a fuse holder (11amp fuse) The original code was modified to reassign the Bed to D9 and the Extruder to D10, and the fan to D8. I have included a zip of the working code. D9 and D10 are now 24 volts for the heaters and D8 is 12v for the extruder fans. I have included below a mark up of the Arduino that shows the hookup. The 5v regulator on the Arduino can not handle the current. I am using a 24v->5v step down (eBay $2) that powers both the Rasberry Pi and the Arduino. You have to make the Arduino power cable from a micro USB cable. The Arduino cable uses standard two pin connectors. The 12v no longer has much current so I use a step down 24v->12v, the 12v is less than 1amp with all fans on full.