Distance Measurement using LIDAR

Distance Measurement using LIDAR

1. Aim

To measure distance as a function of time using VL53L0X and determine oscillation frequency of a mass-spring system.

2. Apparatus / Components Required

  • SEELab3 unit
  • VL53L0X I2C LIDAR module
  • Spring-mass setup (or fixed target for calibration)
  • Connecting wires
  • Data plotting/analysis tool

3. Theory & Principle

VL53L0X estimates distance by optical time-of-flight. Recording distance over time for periodic motion and fitting to: \[x(t)=x_0 + A\sin(2\pi ft+\phi)\]

gives oscillation frequency $f$ and period $T=1/f$.

4. Circuit Diagram / Setup

  1. Connect VL53L0X via I2C interface to SEELab3.
  2. Verify reading with a static surface.
  3. Mount sensor facing oscillating mass on spring.

5. Procedure

  1. Acquire distance-time data for fixed target (baseline check).
  2. Set spring-mass oscillation and record data.
  3. Plot distance vs time.
  4. Fit sinusoidal model and extract frequency.
  5. Repeat for different masses if needed.
LIDAR - Mobile Screen 1

Screen 1

LIDAR - Mobile Screen 2

Screen 2

6. Observation Table

TrialMass (g)Mean distance (cm)Frequency (Hz)Period (s)
1    
2    
3    

7. Results and Discussion

  • LIDAR provided non-contact displacement measurement.
  • Oscillation frequency was measured as ____ Hz for mass ____ g.
  • Non-contact method reduces mechanical loading errors.

8. Precautions

  1. Keep target reflectivity adequate and stable.
  2. Avoid strong ambient IR interference.
  3. Align sensor normal to target motion direction.

9. Troubleshooting

SymptomPossible CauseCorrective Action
No distance outputI2C miswiringCheck SDA/SCL and power pins
Highly noisy signalBad alignment/reflectivityRealign and use reflective surface
Incorrect fitNon-sinusoidal motionReduce damping and use clean oscillation

10. Viva-Voce Questions

Q1. Why use LIDAR for oscillation measurement?

Ans: It provides non-contact, high-resolution position sensing over time.

Q2. How is frequency extracted from distance data?

Ans: By fitting the recorded waveform with a sinusoidal function and reading fitted frequency parameter.