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Integers & Number Line (Smart 2-Way Stepper Temperature & Altitude Tracker)

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Drive on a physical Number Line! Key in integer math problems (e.g. -5 + 8 = +3 or +4 - 9 = -5). A 28BYJ stepper motor car steps left (negative) and right (positive) along a physical number line scale, illuminating LEDs.

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Props & Materials Required

  • •Physical number line track (-10 to 0 to +10) with NeoPixel LED strip
  • •28BYJ-48 stepper motor car mechanism with rack-and-pinion drive
  • •4x4 membrane keypad module
  • •ESP32 controller board
  • •0.96-inch OLED display screen
  • •DFPlayer Mini MP3 module + 3W speaker

Step-by-Step Instructions

1

Input Integer Problem

Key in '-4 + 7' on the keypad.

2

Drive Stepper Car to Initial Position -4

Stepper car drives left 4 steps on track to '-4'. LED at -4 lights up BLUE (sub-zero).

3

Add +7 (Step Right 7 Units)

Press '+7'. Stepper car drives right 7 steps (+1, +2, +3, +4, +5, +6, +7).

4

Arrive at Result +3

Car stops at '+3'. LED lights up GREEN! OLED displays '-4 + 7 = +3'. Speaker confirms integer addition rules!

Why It Works & Notes

Negative numbers represent direction and debt (sub-zero temperatures, below sea level altitude). Driving a stepper motor car left for negative numbers and right for positive numbers turns abstract integer arithmetic into physical movement.