How Laser RangeFinder Modules Work: Principles and Applications

1. Core Principles

Laser ranging modules measure distance using light-speed physics:

Pulsed Time-of-Flight (ToF):

Emits short laser pulses (typically 905nm or 1550nm infrared).

Calculates distance by timing the reflected pulse's round trip (Distance = (Speed of Light × Time Delay)/2).

Example: A 3μs delay ≈ 450m distance.

Phase-Shift Detection:

Uses modulated continuous-wave (CW) lasers.

Measures phase difference between emitted/reflected waves for sub-mm precision.

2. Key Features

FeatureDescriptionRange5mm–5km (varies by power/sensor type)Accuracy±1mm (short-range) to ±1m (long-range)Speed0.1ms–1s per measurementEye SafetyClass 1 (harmless) to Class 4 (hazardous)

3. Critical Parameters

Wavelength: 635nm (visible, short-range) / 905nm (industrial) / 1550nm (eye-safe, long-range).

Power: 1mW–10W (higher power = longer range).

Interface: UART/I²C for robotics, CAN bus for automotive.

4. Real-World Applications

Autonomous Vehicles: LiDAR for obstacle detection (e.g., 905nm modules in Tesla’s sensors).

Construction: Handheld laser tape measures (±1.5mm error).

Space: Lunar/Mars landers use pulsed ToF for terrain mapping.

Pro Tip: For outdoor use, 1550nm lasers outperform 905nm in sunlight due to lower atmospheric absorption.