I am using a VL53L0x for a distance measurement. During the measurements there is an error of 10cm for long range measurements. how could i overcome this?

[ARani.1]

..

[John E KVAM]

Idea one. Carefully read the datasheet about accuracy. One can expect +/- about 3 percent. If the error is outside this range, then we look to calibration. There is a large section on Crosstalk, and how to overcome it. Could that be your issue? (You would under-range as the distances get longer.) There is no crosstalk without a coverglass. So to check this you can try it without a coverglass. Does that work better??

2) As the distances get longer the light spreads. The illumination circle diameter is about 1/2 the distance to the object. Could it be that at the longer distances the target does not fill the entire Field of view? If so, the light might be hitting a wall behind your target. All the photon travel times are averaged. And this multiple target effect might be throwing off your answer.

3) Can you increase the timing budget. 4x the time, will 2x the accuracy.

[ARani.1]

Thank you

[Eleon BORLINI]

Hi @ARani.1​ , please let us know if you solved your issue... thanks and regards

[ARani.1]

Yes the results are consistent with +/- 3 percent error but not accurate.

[ARani.1]

I will be using this sensor for measurement of water in the underground tank.

Do this effect the sensor operation and is it water resistant?

[John E KVAM]

ARani - The VL53L0X is NOT water resistant. In order to let the light out and back in the raw silicon has to be exposed. We do put a filter over the top, but the raw silicon is more exposed than other chips. If you are going to use it under water is has to be in a very well sealed enclosure.

[ARani.1]

I have tried enclosing it in a small transparent plastic container but this was not helpful since container was considered as target surface by the sensor

[ARani.1]

 it will be mounted to TOP OF A LARGE WATER TANK of 200,000L capacity. Since the tank is in the exteriors (exposed to Sun light), there is Humidity inside the tank in the open space between water and the sensor.

What type of harm this can cause to the sensor?

[John E KVAM]

I don't think a little humidity will hurt the sensor any more than any other electronics. But it should be a simple matter to build a water-proof enclosure, would it not?

If life were perfect the sensor would sit pressed flat against the coverglass. You could put a rubber gasket around the sensor. The heat generated by the laser would be enough to keep any humidity from condensing. At least I would think so. (I know lots about our part - but not so much about humidity.)

[John E KVAM]

>>>I have tried enclosing it in a small transparent plastic container...

Push the sensor flush with the 'glass' of the container. We use the sensor behind the glass in nearly a billion cellphones, so we know that works. (Sorry for Bragging.)

You will get accurate numbers for close distances. Some of the photons will reflect off the coverglass, but they will be dwarfed by the ones from the target. At the longer distances the 'crosstalk' becomes more of an issue. We have a way to calibrate this out. Read the section of the datasheet on Crosstalk Calibration. It will fix you right up.

And you might consider the VL53L3CX or the VL53L1X. The software on the L3 is larger, but the extra range might be worth it. The L1X is more expensive, but it has a lens to further increase the range. In a large tank that might help. Also if you are looking for the surface of the water, I've had better luck with the VL53L1X.

[ARani.1]

I am trying out with glass container of 2mm thickness result are not consistent can u please suggest me what can be done?

[ARani.1]

can u please suggest me how do i calibrate for an accurate long range.i have tried out with ur previous suggestions but the error is more than 3% of actual distance.

here is my code:

#include <Wire.h>

#include <VL53L0X.h>

VL53L0X sensor;

void setup()

{

 Serial.begin(9600);

 Wire.begin();

 sensor.setTimeout(1000);

 if (!sensor.init())

 {

  Serial.println("Failed to detect and initialize sensor!");

  while (1) {}

 }

 sensor.setSignalRateLimit(0.2);

 sensor.setVcselPulsePeriod(VL53L0X::VcselPeriodPreRange, 18);

 sensor.setVcselPulsePeriod(VL53L0X::VcselPeriodFinalRange, 14);

}

void loop()

{

 Serial.print(sensor.readRangeSingleMillimeters());

 if (sensor.timeoutOccurred()) { Serial.print(" TIMEOUT"); }

 Serial.println();

}