Sprint 1

What we did in Sprint 1:

  • Decided on this project
  • Spun up team:
    • Set up team communication channels
    • Set up software and mechanical design toolchains
    • Decided on design practices
    • Discussed expectations, roles, and team dynamics
  • Made a proof of concept using DC motors and hot glued string
  • Calculated the change-of-basis math
  • Upgraded the proof of concept with 3D printed parts

Current Status:

sprint1 deliverable

The sprint 1 system. Draws hardcoded points using dc motors and timing

marker collets

A close up of the marker with 3D printed collets

dc motor

What we learned:

  • Proof of concept works
  • DC motors are not precise enough


  • Ink is too light, need more pressure on pen
  • Need to design a tool changer (draw/erase/move)
  • Uncertain about precision of positioning
  • SVG Computer Vision processing
    • We have a working manual toolchain, automation would be nice
  • Stepper motors
    • Speed and torque uncertain

Future Considerations:

  • Possibly build a CNC gantry
    • High precision at the loss of simplicity
    • No sway on the pen
  • Tool changer
    • Servo with many tools on its end
      • + Compact
      • - Not versatile (limited number of tools)
    • Solenoids
      • + More extendable with number of tools
      • - Too much force? (Breaking pen tips, bouncing off the wall)
      • - High current (cannot make wireless/battery powered)

Next Sprint Deliverables:

  • Implement stepper motors
  • Have a better cable/string system
  • Tool changer (end effector) with pen/erase/move
  • Draw vector graphics from a computer