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Angles as Turns (Smart Servo Robotic Arm & Protractor Goggles)

Source:

Control a 2-DOF robotic arm using a rotary encoder dial. As the child turns the knob, servo motors rotate through exact angles (30°, 90°, 120°, 180°), while an OLED display classifies the angle as Acute, Right, or Obtuse.

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Props & Materials Required

  • •2-DOF robotic arm mechanism with SG90 micro servo motors
  • •KY-040 rotary encoder dial (0° to 180° angle input)
  • •OLED angle display panel with protractor overlay graphic
  • •ESP32 / micro:bit V2 controller
  • •DFPlayer Mini MP3 module + 3W speaker
  • •Laser pointer on arm tip

Step-by-Step Instructions

1

Turn Encoder Knob to 45 Degrees

Turn knob to 45°. Robotic arm joint rotates 45°.

2

Read OLED Screen & Classification

OLED displays 'Angle: 45° | Type: ACUTE ANGLE (< 90°)'.

3

Set 90 Degree Right Angle

Turn knob to 90°. Servo arm locks into a square L-shape.

4

Right Angle Audio Confirmation

Green LED flashes! Speaker announces: '90 DEGREES! PERFECT RIGHT ANGLE! Found in book corners, windows, and door frames!'

Why It Works & Notes

Angles represent rotational turns (turns of a clock hand, arm joints, door hinges). Rotating a physical robotic arm joint with a rotary dial while seeing the live angle readout (90° = Right Angle) connects geometry with mechanical engineering.