Proximity Detection with Arduino Nicla Vision

Overview

In this tutorial you will use the Nicla Vision to detect proximity, thanks to the Time of Flight (ToF) sensor VL53L1X.

This tutorial teaches you how to create a sketch that will blink the built-in RGB LED and control the speed of its blink with the proximity values. It can be useful for future projects where there is the need to control the camera only when something is detected in front of the sensor.

Goals

• Set up the needed libraries
• Learn how to interact with the proximity readings
• Change the RGB values of the LED

Required Hardware and Software

• Nicla Vision
• VL53L1X library (Available in the Library Manager)

Instructions

Time of Flight Sensor

To make sure that the sketch works properly, the latest versions of the Arduino Mbed OS Nicla core and the VL53L1X library need to be installed. Both can be found inside the Arduino IDE.

• The Arduino Mbed OS Nicla core can be found in the boards manager...
• The VL53L1X library can be found in the Library manager

If you are using version 2.2.0 or later of the Arduino IDE, install the VL53L1X library as follows:

• In the left bar of the Arduino IDE, click on the Library Manager.
• Search for VL53L1X.
• Click the VL53L1X entry in the list, authored by Pololu.
• Click Install. More detailed instructions on how to install a library can be found here.

Include the Needed Libraries and Objects Declaration

First of all, declare the sensor's class so you can access it later on in your sketch. You can use variables to control the time elements in the sketch. This will make sure that the readings stay accurate over time.

Copy
1#include "VL53L1X.h"
2VL53L1X proximity;
3
4bool blinkState = false;
5int reading = 0;
6int timeStart = 0;
7int blinkTime = 2000;

Initialize the Proximity Sensor and the LED

Inside the setup you need to initialize and configure the proximity sensor. Also, the RGB LED needs to be set as an output to make it light up and enable you to change its behavior.

The LEDs are accessed in the same way as on the Portenta H7: LEDR, LEDG and LEDB.

Copy
1void setup(){
2    Serial.begin(115200);
3    Wire1.begin();
4    Wire1.setClock(400000); // use 400 kHz I2C
5    proximity.setBus(&Wire1);
6    
7    pinMode(LEDB,OUTPUT);
8    digitalWrite(LEDB, blinkState);
9    
10    if (!proximity.init()){
11      Serial.println("Failed to detect and initialize sensor!");
12      while (1);
13    }
14
15    proximity.setDistanceMode(VL53L1X::Long);
16    proximity.setMeasurementTimingBudget(10000);
17    proximity.startContinuous(10);
18  }

Make sure you initialize

Wire1

Wire1

Control the Speed of the Blink

The sketch is going to get the reading on every loop, store it and then the state of the LED will change until the time is up and another proximity reading is taken.

Copy
1void loop(){
2    reading = proximity.read();
3    Serial.println(reading);
4
5    if (millis() - timeStart >= reading){
6      digitalWrite(LEDB, blinkState);
7      timeStart = millis();
8
9      blinkState = !blinkState;
10    }
11  }

Complete Sketch

Copy
1#include "VL53L1X.h"
2VL53L1X proximity;
3
4bool blinkState = false;
5int reading = 0;
6int timeStart = 0;
7int blinkTime = 2000;
8
9void setup() {
10  Serial.begin(115200);
11  Wire1.begin();
12  Wire1.setClock(400000); // use 400 kHz I2C
13  proximity.setBus(&Wire1);
14
15
16  pinMode(LEDB, OUTPUT);
17  digitalWrite(LEDB, blinkState);
18
19  if (!proximity.init()) {
20    Serial.println("Failed to detect and initialize sensor!");
21    while (1);
22  }
23
24  proximity.setDistanceMode(VL53L1X::Long);
25  proximity.setMeasurementTimingBudget(10000);
26  proximity.startContinuous(10);
27}
28
29void loop() {
30  reading = proximity.read();
31  Serial.println(reading);
32
33  if (millis() - timeStart >= reading) {
34    digitalWrite(LEDB, blinkState);
35    timeStart = millis();
36
37    blinkState = !blinkState;
38  }
39}

Here is a demo video of the example running on the Nicla Vision:

API

Wire1

void

uint8_t

void

VL53L1X::Short

VL53L1X::Medium

VL53L1X::Long

VL53L1X::Unknown

void

VL53L1X::Short

VL53L1X::Medium

VL53L1X::Long

VL53L1X::Unknown

enum DistanceMode 

void

uint32_t

void

void

void

uint16_t

bool

void

uint16_t

bool

Conclusion

In this tutorial we went through how to get readings from the ToF sensor and how to use these readings to change how the built-in LED behaves. At the end of the tutorial you can also find a reference list for the ToF library.