Can the VL53L5CX work with a non-perpendicular surface?

[DCabl.1]

Hi all, first post here!

I'm working on a project that I was planning to use the VL53L5CX sensor where it is installed at about 5/6ft above the floor and pointed down at an angle of around 45°. The goal is to be able to calculate the surface of the floor and if any objects come into view and there respective location in the field of view. I'm currently testing with a Sparkfun sensor and an ESP32 board. I have no issues when pointed at the surface perpendicular, but when I try and give it much of an angle it just gives me many 0's for the array. After several minutes these zeros will be populated with data, but I don't think its updating very frequently. The floor surface is either carpet or roughened concrete. I'm not sure if I'm working outside of the capabilities of this sensor or just a newb as this is my first time working with the time of flight sensors?

[Zhiyuan.Han]

Hi Deanc

For your question, there are two possible reasons.

The first one could be return signal rate is too less, this depends on the target surface reflective. you can do a similar test with a white wall to check if is due to too weak signal come back.

The second one could be beyond L5CX ranging ability: for your test conditions, let's take 6ft (around 1.8meter) for calculation, if you tilt the sensor with 45 degree, as the FOV is 45 degree, so the biggest tilt angle for the border zones will be 45+22.5 =67.5 degree. and the real distance at the border zones will be 1.8 / cos(67.5)= 4.7 meter. which is longer than the maximum ranging ability of L5CX(4meter in 4*4 mode). of course this will only happen on one side zones, on the opposite side zones, there should be no issue.

Br

Zhiyuan.Han

[DCabl.1]

Thanks for the quick response!

For issue number 1, I suspect that this is my main issue. Is there a recommended way to help increase the signal rate received back in the sensor with a more reflective surface? Will playing with the sharpness or target modes have any noticeable effects? From my testing its challenging for me to notice any notable improvements. From UM2884 it seems that having the target mode in the "strongest" may give me the best hope for success with sharpness around 25%. Any expert advise here will be greatly appreciated!

For number 2, I will test and a larger angle and see if that helps. Maybe it will help with number 1 as well.

[Zhiyuan.Han]

Hi Deanc

I think your case is reaching the limit of device ranging ability, as you know TOF device need enough signal come back for ranging data calculation, if the target reflected signal is quite less, it will be submerged into noise signal, and lead non-valid distance report. one suggestion is you can set device to continuous mode and decrease the range frequency to 1HZ to see if help. if still not help, you can try our new multi zone device VL53L8CX, it will be more powerful than VL53L5CX.

Br

Zhiyuan.Han