Skip to main content

VL53L1X ToF Laser Distance Sensor - How it works

The VL53L1X ToF Laser Distance Sensor is a high-performance Time-of-Flight (ToF) laser-ranging sensor by STMicroelectronics.

VL53L1X ToF Laser Distance Sensor on the board
VL53L1X ToF Laser Distance Sensor on the board

Important note​

⚠️
Important: Before starting to work with the sensor, the orange protective sticker needs to be peeled off for the laser to emit and be detected properly!
VL53L1X ToF Laser Distance Sensor remove sticker
Remove the protective orange sticker before use

Datasheet​

For an in-depth look at technical specifications, have a look at the datasheet:

VL53L1X ToF Laser Distance Sensor Datasheet

View full VL53L1X ToF Laser Distance Sensor datasheet

How the sensor works​

The VL53L1X is an advanced and compact Time-of-Flight (ToF) distance sensor, meaning it measures how long the light has taken to bounce back to sensor unlike IR sensors that measure amount of light reflected back to them. It uses a very narrow light source, which makes it very precise at determining the distance of the surface in front of it.

VL53L1X Laser Sensor image

Measurement process​

1. Laser Pulse emmission

  • The sensor emits a quick pulse of invisible infrared light using a tiny laser (VCSEL - vertical-cavity surface-emitting laser) at 940nm wavelength.

2. Bounce Back

  • The emitted light pulse travles through the air, hits an object, and reflects back to the onboard sensor.

3. Single Photon Detection

  • The reflected light is captured by a very sensitive array of detectors called SPADS (Single Photon Avalanche Diodes), capable of detecting single photons of light.

4. Time measurement

  • The sensor's built-in microcontroller precisely calculates how long it took for the light to go out and reflect back. Since the speed of light is constant, this time can be used to calculate the exact distance to the object.

Additional features​

  • Programmable region of interest (ROI)
    • ROI size and position are programmable.
    • Choose custom FoV from 4x4 SPADs (min.) up to 16x16 SPADs (full FoV)
  • Shutdown Pin
    • SHTD pin allows to put the sensor into hardware standby mode
  • GPIO Interrupt
    • Digital output that acts as an interrupt line from the sensor to your microcontroller
    • It can signal new distance measurement, a threshold condition has been met

Qwiic I²C communication​

This product uses I²C communication. The breakout board operates with a default I²C address of 0x29.