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ENGINEERING JOURNAL

Jingyan Ling

06/27/2019 (Thur)

  • Compile OldRoCo repo
    • Record of modification:
      • ++line 8 of vstart.sh
      • --> pip install -r requirements.txt --user
  • Export paperbot dxf file : graph-silhouette.dxf to OnShape
    • Record of Tips:
      • Onshape does not read dxf file as its own saved unit. Manual settings needed when import.
      • onshape_dxf_unit
  • Draw circuit diagram as CAD on Onshape
    • Multiple connection approaches:
      • Cross shape of 0.039 in
      • Cross shape of 0.049 in
      • Octangular shape of 0.049 in
      • connection_approaches.png
      • actual_connection_cuts.JPG
    • Note and issue:
    • Octangular shape is the best connection approach so far, but none of approach has stable conductivity. More research is needed.
    • Scratches can be made easily when attaching microcontroller to the sheet. Potential disconnection may occur due to such scratches on metal layer.
  • Export 2D CAD drawing with PCB to SVG for silhouette cameo
    • Record of Tips:
      • OnShape unit need to be consisted with unit setting in Inkscape (default: mm)
    • Plugin Inkscape-silhouette cannot take multiple types of trace for cutting.
      • Different trace (especially cut and etching) need to be sent separately. Use coordinate tool of Inkscape to ensure separated cuts have same origin.
    • TODO:
      • Cut and etching from same Inkscape file

06/28/2019 (Fri)

Connection and fabrication approach confirmed !
  • Confirm that copper tape has better conductivity than aluminum sheet when attaching microcontroller pins through H-shape cut

    • Copper tape is harder to be scratched, which provides less risk of disconnection during assessmbly.
  • Etching on copper type isolates connections

  • Research on PCB editor

    • EAGLE
      • EAGLE cannot import .pcb file
      • svg can be exported but not imported
      • Custom library needed if doing schematic design
    • KiCad
      • Can import .pcb file
      • svg can be exported but not imported
    • LayoutEditor
      • support multiply file type
      • svg can be exported with different color makers as multiple layers
      • include open-sourced auto-router freerouting
  • Auto-routing package:

    • TopoR
    • Python-PCB
    • FreeRouting
  • Approaches:

    • A. convert SVG/DXF file to schematic/board design of PCB. Use KiCAD or EAGLE to do auto routing.
    • B. develop algorithm on auto routing for single layer svg/dxf file. (path finding problem)
Approach A
  • Use regular shape board for PCB in EAGLE/KiCAD

    • image processing: divide alternative shape of paperbot to multiple rectangles (openCV)

    • Pull required connections and place additional header pins around edges of each rectangle

  • Make each connection pin to be two parallel connections so auto-router does parallel trace for each wiring.

    • Etching a pair of parallel trace provides isolation, and leave the space between traces to be conductible.
  • Build Library for schematic design

    • Schematic design helps with router to know desired connection
    • Additional header pins at each side of kink mark

06/29 & 06/30/2019 (Sat & Sun)

Approach B
  • Potential needed functions of packages

    • A package draws on DXF file through script
    • A script that pulls out pins' coordinate on paper chassis
      • Or a image process package (OpenCV) that reads pins' coordinate on paper chassis
    • A package solves multi-node path finding problem*
Record of Research
  • Python Pathfinding package:
  • Python DXF editor:
  • Going through tutorials of ezdxf
    • All lines on paper spacelayer0

07/01/2019 (Mon)

  • Continue the dxf processing with 'graph-silhouette.dxf'
Record of tips:
  • Put circuit design on a new layer of dxf drawing

  • Use block feature to draw similar pattern

  • Blocks are symbol in Inkscape. Convert symbol to path

    • Edit > Clone > Unlink Clone (Shift+Alt+D), and you have a group, ungroup (Object > Ungroup, or Shift+Ctrl+G) and edit
  • Convert text to path

    • Path combine (Ctrl+K)
  • Test fabrication with different drawing settings

    • Layers can be cut separately but toggling visibility
    • Set cuts with same intensity and feedrate on same layer
    • Entities' layer can be changed through Entity.dxf.layer

07/02/2019 (Tue)

  • Continue the dxf processing
  • Following tasks can be completed by running the code:
    • Able to detect pin center coordinate
    • Able to draw arbitrary shape around the pin center
    • isolation_circuit.png