S3/BlocklyProp - best quality traces

Our middle school has an offer to display S3 traces in our public library. I want the students to re-run them to be as polished as possible. We use about 60 cm square sheets of poster paper. Below is what we do for best results. Any more suggestions?

Run at slow speed:
reduces over-shoot and squiggle coming out of turns.
however, leaves larger "bleed dot" when pivot turning

Get paper relaxed and as flat as possible:
use very flat table surface (laboratory bench)
carefully clean bench and paper of any small debris
relax paper with slightly damp cloth, stretch and tape to table then quick dry with fan.

Check wheels / tires:
tires cleaned witch damp cloth and dried by fan.
carefullly clean any small debris that will intro error to encoder setting of circumference.
tires well seated
tail ball clean and free-running
no hair wrapped around axles

Keep one set of markers just for high-quality traces
Check that tip is sharp (not worn to be rounded, no extra fuzz)
ink is flowing (not slightly dry)
Shim around marker so is tightly seated in port:
eliminates some wiggle during the turns
reduces wiggle from re-seat as come out of turn

Size and position
double check scaling value in code so result fits on paper with margins correct for intended mat & frame
use preliminary run to hang on wall, back up and judge if want changes before final
establish start position and angle (before every trial run we make soft pencil marks at 3 contact points so can replicate)
If desired, scale so leave space on paper to tape on print of block code, print of text code and/or student name

At run:
Insert marker at last minute to reduce bleed spot
clear plenty of space beyond paper for wheels going off paper during turns

Include at start a pause and count-down beeps so know exactly when motion will start.

Experiment with papers of different surface finish and thickness
Experiment to see if there is a straight-line speed which is optimal: probably slow, maybe not slowest
Experiment to see if there is a turning speed...
Try thin-point markers instead of thick sharpies (but may not be dark enough to see the trace at a viewing distance)
Try lifting pen by hand during the pivot turns (we have not had success with sevor-lifter. A student might look at improvement using 3D printed parts)
Somehow use Foam-Core (and maybe vacuum press) to keep paper as flat as possible.

Any other suggestions?

Thanks, John


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