We've switched back to limit switches for X and Y homing, now on a custom board near the X motor. The Z limit switch is also custom now, with an AUX port for extra peripherals. There's a dedicated cable chain for both the X and Y axis. Cable management is greatly improved for the machine as well.

CAD Updates

• Control Box
  • Almost all mounting hardware for electronics and pneumatics have been integrated into a single control box.
  • Tool-free valve and pump mounting
  • Complete vibration isolation for both pumps
  • Cover has flexure buttons that allow much easier BOOT and RESET operation
• Cabling
  • Both the X and Y axis now have dedicated drag chains
  • X drag chain has a dedicated structural PCB for reducing sag across the build area
  • All moving cabling are now full silicone-sheathed
  • The new cable-splay print cleanly distributes cabling and pneumatics to both nozzles
• Bottom Camera
  • The bottom camera is completely new, with a wider field of view, and improved driver chip
  • The bottom camera mount has been shifted to accommodate the new wide-angle lens for the bottom camera
  • The staging plate foot is now attached with two thumbscrews, removing the chance of the foot falling off
  • The staging plate foot now comes to more of a point, removing the chance that it gets caught at an angle.
  • The bottom light diffusion has been greatly reworked to allow for better printing, even diffusion, and minimal occlusion of the bottom camera.
• Top Camera
  • The top camera is completely new, with a wider field of view, and improved driver chip
  • The top camera and top ring light are now held into x-gantry-back with a single print, making them much more rigidly integrated into the head
  • Improved thermals for the top camera, allowing better airflow during head movement
• Misc
  • The X and Y axis are now homed with the XY limit switch board, removing sensorless homing
  • The Z limit switch has been replaced with a custom PCB that also breaks out an AUX port
  • Nozzle masks are now included on both nozzles, helping isolate the background during machine vision operations

REV05 Motherboard

• Second driver dedicated to the Y axis
• Full test point coverage on the bottom side of the PCB
• Full XYZ limit switch support
• Almost fully SMT (closes #696 )(closes #703 )
• DIAG pins from all stepper drivers are still attached to the STM32 for future software updates that allow for stall detection
• Complete redesign of power electronics providing a much higher current capability on the 5v rail for future applications (closes #708 )(closes #665 )
• Voltage indicator LEDs are now present for all three bus voltages
• BOOT and RESET pins on the STM32 are broken out for external firmware flashing
• Full ESD protection on all exposed pins (closes #698 )
• Fully integrated stepper motor drivers for better thermals, reliability, and current sensing capability (closes #697 )(closes #704)
• Refined AUX port on the motherboard for additions and modifications
• Aux pin broken out to the Z limit switch PCB
• An optional fan port has been added, although not needed in operation
• A buzzer has been added
• "Chimera" jumper allows software to determine via GCode if the LumenPnP it's controlling is stock, or needs more customized configuration
• Hardware ID pullup resistors allow software to determine LumenPnP hardware version via GCode (closes #707 )
• Solenoid valve control pins have been moved to hardware PWM pins on the STM32 to allow for lower current operation (closes #701)
• The diode that allows USB VBUS to power the STM32 is now DNP by default, as this caused issues with boot sequence in the REV04 motherboard (closes #719 )(closes #666)

This machine is the result of hundreds of talented and enthusiastic folks, both at Opulo and within our community. Thank you to everyone that has contributed to making the LumenPnP v4 the incredible machine that it is. In particular, I'd like to thank all members of the review-squad that helped with the REV05 motherboard design, Thea Flowers, Justin Nesselrotte, Gonçalo Pereira, Stuart Pittaway, and David Smith.