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VCSEL signals interferences for closed sensors (VL53L1X)

AAmor.2
Associate II

Hello,

I am designing a system of multiple VL53L1X sensors placed around a drone. My question is whether two sensors are closed and oriented towards the same direction , is it possible that the VCSEL signal from one could affect the measure computation of the other ?

Whether it's the case, exists it an angle (45°/90° of direction difference) where these interferences will disappear ?

Another point is with a timing budget of 20ms for example, how many time the sensors radiate the signal before computation ?

Thanks for your future help.

1 ACCEPTED SOLUTION

Accepted Solutions
John E KVAM
ST Employee

it's interesting that they don't generally interfere. One guy on this forum told me that pointed directly at each other at 5cm he got some interference.

I built a 2D lidar system using 9 sensors around a half circle.

https://www.st.com/content/st_com/en/products/embedded-software/proximity-sensors-software/stsw-img017.html

STSW-IMG017

2D LIDAR using multiple VL53L1X Time-of-Flight long distance ranging sensors

And there is a youtube video you can watch. Go to youtube.com and search for VL53L1X 2D lidar.

The sensor does not use much time between ranges to 'compute'. I'd consider that negligable. The I2C transmission of the resuts takes longer.

But it does take two separate ranges at different pulse timings. (Done to prevent Radar Aliasing -which you can Google.)

Those two ranges are going to give you different answers if you are moving. And you will get an error code. I'd consider this code a warning and ignore it.

The distance you get will be the distance at one of the timings.

Good luck.


In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question. It helps the next guy.

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1 REPLY 1
John E KVAM
ST Employee

it's interesting that they don't generally interfere. One guy on this forum told me that pointed directly at each other at 5cm he got some interference.

I built a 2D lidar system using 9 sensors around a half circle.

https://www.st.com/content/st_com/en/products/embedded-software/proximity-sensors-software/stsw-img017.html

STSW-IMG017

2D LIDAR using multiple VL53L1X Time-of-Flight long distance ranging sensors

And there is a youtube video you can watch. Go to youtube.com and search for VL53L1X 2D lidar.

The sensor does not use much time between ranges to 'compute'. I'd consider that negligable. The I2C transmission of the resuts takes longer.

But it does take two separate ranges at different pulse timings. (Done to prevent Radar Aliasing -which you can Google.)

Those two ranges are going to give you different answers if you are moving. And you will get an error code. I'd consider this code a warning and ignore it.

The distance you get will be the distance at one of the timings.

Good luck.


In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question. It helps the next guy.