This simple "broom" is activated by moving the Z axis all the way down, tripping a sense switch. It then uses a 1 channel motor controller, driven by a Picaxe 8, to move a plastic "broom" (hence the name) across the build plate, removing the print and presumably flinging it into a box.
The firmware is designed to compensate for non-rigid mounting, to allow for temporary installation using zip ties.
This archive contains the firmware, layout, and schematic for it. There is also a python file for generating gcode to send the print bed to the broom location and activate the broom.
Parts list:
1x Picaxe 08, Picaxe 08M, or Picaxe 08M2
1x L298 (through-hole)
3x Sense switches
1x Gear motor
1x Spring
1x Threaded rod
1x 22k resistor
1x 3904 transistor
1x IRFZ series MOSFET
2x Filter capacitor
8x 1N4001 diode
Operation