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VL53L3 and Sunlight

Vandr.1
Associate II

Hello,

I have a problem with VL53L3 sensor measurements. When sunlight hits the sensor, the measurement is distorted, and the measured distance becomes small. Are there any settings for the sensor to remove this glitch when the sun's rays hit?

1 ACCEPTED SOLUTION

Accepted Solutions
Anne BIGOT
ST Employee

Hello

This is explained by the fact that the photons the sensor emits are not marked in any way save that they are at 940nm. So there is a band pass optical filter on the Receive side to eliminate all the other photons.

But the sun emits a lot of 940nm light.

At the beginning of the range, we take a measure of the 940nm light. This is the Ambient that you can get after the range.

What we are looking for is that signal over ambient.

But if the Single Photon Avalanche Diode (SPAD) array is fully saturated by the sun, there is nothing we can do.

But generally at the closer distances, the target obscures some of the sunlight and we can get a range. Also direction is important. Sunlight passing at 90 degrees to the sensor and the target has less effect on the sensor.

All this taken together means that a sensor that can range to several meters indoors, will be limited to maybe a half meter in bright sunlight.

But the good news is that if there is a returned value, it will be right. The sunlight stops the ability of the sensor to work, but does not corrupt the answer if there is one.

If you want to reduce the glitches it is recommanded to increase the sampling period to decreases noise but it also reduces the effective max convergence time and increases power consumption.

Hope it helps,

Anne


Our community relies on fruitful exchanges and good quality content. You can thank and reward helpful and positive contributions by marking them as 'Accept as Solution'. When marking a solution, make sure it answers your original question or issue that you raised.

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1 REPLY 1
Anne BIGOT
ST Employee

Hello

This is explained by the fact that the photons the sensor emits are not marked in any way save that they are at 940nm. So there is a band pass optical filter on the Receive side to eliminate all the other photons.

But the sun emits a lot of 940nm light.

At the beginning of the range, we take a measure of the 940nm light. This is the Ambient that you can get after the range.

What we are looking for is that signal over ambient.

But if the Single Photon Avalanche Diode (SPAD) array is fully saturated by the sun, there is nothing we can do.

But generally at the closer distances, the target obscures some of the sunlight and we can get a range. Also direction is important. Sunlight passing at 90 degrees to the sensor and the target has less effect on the sensor.

All this taken together means that a sensor that can range to several meters indoors, will be limited to maybe a half meter in bright sunlight.

But the good news is that if there is a returned value, it will be right. The sunlight stops the ability of the sensor to work, but does not corrupt the answer if there is one.

If you want to reduce the glitches it is recommanded to increase the sampling period to decreases noise but it also reduces the effective max convergence time and increases power consumption.

Hope it helps,

Anne


Our community relies on fruitful exchanges and good quality content. You can thank and reward helpful and positive contributions by marking them as 'Accept as Solution'. When marking a solution, make sure it answers your original question or issue that you raised.

ST Employees that act as moderators have the right to accept the solution, judging by their expertise. This helps other community members identify useful discussions and refrain from raising the same question. If you notice any false behavior or abuse of the action, do not hesitate to 'Report Inappropriate Content'