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Measuring Length (Smart Laser & Ultrasonic Digital Measuring Tape)

Source:

Construct a handheld digital measuring device containing a laser pointer and HC-SR04 ultrasonic sensor. Aim at classroom walls, desks, and doors to instantly read distances in cm and m on an LCD screen.

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Props & Materials Required

  • •Handheld 3D-printed/cardboard laser tape housing
  • •Red laser diode pointer module
  • •HC-SR04 ultrasonic distance sensor
  • •ESP32 controller board
  • •16x2 LCD display screen
  • •DFPlayer Mini MP3 module + 3W speaker

Step-by-Step Instructions

1

Aim Laser Pointer at Wall

Point the red laser beam at a wall across the classroom.

2

Press Measure Button

Press the trigger button. Ultrasonic sensor emits 40kHz sound burst and receives echo.

3

Read Distance on LCD Screen

LCD displays 'Distance: 345 cm (3.45 Meters)'. Speaker announces length aloud.

4

Desk Perimeter Calculator

Measure Length (120 cm) and Width (60 cm) of a desk. Press 'Perimeter'. Controller calculates P = 2*(L+W) = 360 cm!

Why It Works & Notes

Measuring room dimensions with tape measures can be cumbersome. Using a handheld ultrasonic-laser device gives instant cm/m readouts, allowing children to calculate perimeters of desks and rooms effortlessly.