Stemoto LogoStemoto
Back to Directory

Practical Geometry (Smart Compass & Protractor Servo Drafting Arm)

Source:

Construct geometric shapes automatically! Build a 2D 2-servo drafting plotter arm. Input radius (e.g. 5 cm circle) or angle bisectors on a keypad; the servo arm lowers a marker pen and draws exact geometric constructions on paper.

Categorisation

Props & Materials Required

  • •2D 2-DOF SCARA servo drafting plotter arm with drawing marker pen
  • •4x4 membrane matrix keypad module
  • •ESP32 controller board
  • •0.96-inch OLED display screen
  • •DFPlayer Mini MP3 module + 3W speaker

Step-by-Step Instructions

1

Select Construction Task

Select task on keypad: 'Construct Circle of Radius = 6 cm'.

2

Servo Arm Calculates Polar Path

ESP32 calculates 360° trigonometric polar coordinates (x = r cos θ, y = r sin θ).

3

Plotter Arm Draws Exact Circle

2-servo arm lowers pen onto paper and draws a smooth 6 cm radius circle!

4

Perpendicular Bisector Proof Audio

Select 'Angle Bisector 90° → 45°'. Plotter arm bisects 90° angle into two exact 45° arcs! Speaker confirms geometric proof!

Why It Works & Notes

Practical geometry involves drawing exact circles, line bisectors, and angle bisectors. Programming a 2-servo plotter arm to calculate polar coordinates (r, θ) and draw precise circles on paper connects compass geometry with robotic CAD plotters.