Ninja Clock

This project is a variation of the Ninja Timer: Giant 7-Segment Display project. Notably, the Ninja Timer's published .SVG files were meant to be cut out by a laser cutter, but I was using a CNC router instead. This required quite a bit of fiddling, and reimporting the plans into FreeCAD, so that I could generate the milling paths.

Huge thanks to Keith Packard for his help with this project and the use of his CNC router. :)

Materials

• TAP Plastics
  • Acrylic panels
    • 12x 16"x12" Opaque Black, 3mm
    • 4x 16"x12" Opaque Black, 6mm
    • 4x 16"x12" Lighting White - 45% Light Transmission, 6mm
  • 1x Small BD-25/2 Hypo Applicator
  • 1x Weld-On 3 Cement 4oz
• 226x WS2812B LED strip
  • cut to 28x 8-LED long segments + 2 individual LEDs for colon
• Fastener Hardware
  • 24x #6-32 2" bolts
    • 1x 91251A159 Black-Oxide Alloy Steel Socket Head Screw, 6-32 Thread Size, 2" Long, Packs of 50
  • 24x #6-32 1/4" nuts
    • 1x 90760A170 Steel Narrow-Profile Hex Nuts, Black-Oxide, 6-32 Thread Size, 1/4" Wide, Packs of 10
  • 48x #6-32 1/4" spacers
    • 2x 90176A133 Nylon Unthreaded Spacers, 1/4" OD, 1/4" Long, Black, Packs of 25
  • 24x #6-32 small washers (top)
    • 2x 98029A025 Black-Oxide Steel Washer for Number 6 Screw Size, General Purpose, 0.156" ID, Packs of 25
  • 24x #6-32 large washers (back)
    • 1x 91090A100 Zinc-Plated Steel Washers, Oversized, for Number 6 Screw Size, 0.141" ID, 0.625" OD, Packs of 50
• Adafruit electrical stuff
  • 1x Pixel Trinkey - USB Key for NeoPixel
  • 4x 3-pin JST SM Plug + Receptacle Cable Set
    • for connecting between digits
  • 1x 5V 10A switching power supply
    • for driving the LEDs
  • 1x Female DC Power adapter - 2.1mm jack to screw terminal block
• lots of 22awg stranded-core wire, black, red, white
• 48"x24" 1/2" plywood (backing)

Milling and Stacking Order

• Bolt
• Small washer
• Top layer, segments fit through these, glue to inset ledge below
  • 1x cutF-top-dot-3mm.nc
  • 1x cutF-bottom-dot-3mm.nc
  • 2x cutF-none-3mm.nc
• 4x cutD-inset-6mm.nc
• Spacer
• 4x cutE-inset-3mm.nc
• 4x cutC-jig-3mm.nc
  • LEDs go behind this
• Spacer
• 4x cutB-spacer-6mm-white.nc
  • I ended up using 4x cutB-segments-6mm.nc to get smaller segments
• Plywood
• Large washer
• Nut

Trinkey setup

• Copy code-over-usb.py to Trinkey USB CircuitPython drive
• Run clock-over-usb.py to drive Trinkey with current time

SVG to FreeCAD Workflow

• export 1 digit from Inkscape
  • name it with thickness
• FreeCAD:
  • new project
  • Part Designer, yellow +part button, blue +body button
  • import SVG as geometry
  • Draft mode, convert to Sketch
  • drag Sketch to body
  • Part Designer Mode, Pad to desired thickness
  • CAM mode, add Job
  • pick 3.175 tool
    • H speed: 40
    • V speed: 20
    • Spindle: 18000
  • use stock with 0.5mm +/-z borders, 1.0mm xy
  • pick upper corner vertex of lower left corner of stock, job: set origin
  • add operations...
    • shift-E, swipe R-to-L to select everything touched
    • shift-E, swipe L-to-R to select only what is completely covered
    • hold ctrl to add to existing selection