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Selecting ST ToF Modules for Distance Measurement During Free Fall


Hello community,

I am working on a project that involves measuring a precise distance of 2 meters from the ground during an object’s free fall. I am considering using Time-of-Flight (ToF) modules from ST for this purpose and would like some guidance on which modules would be best suited for this application.

Could you please advise if the VL53L8 module, or any other ST ToF modules, would be capable of accurately measuring a 2-meter distance in a free-fall scenario? Additionally, I am concerned about environmental factors such as bright sunlight and fog. How would the VL53L8 module perform under these conditions? Are there any specific settings or considerations to ensure reliable measurements?

Thank you for your assistance.

ST Employee

I love the idea - but sadly it will not work. 

The best speed you can get out of the VL53L8CX is 60 frames per second in 4x4 mode, and then you have to do the read-out of the data. 

I'm afraid that you will have hit the ground before you get the interrupt. 

And during that 1/60 of a second, you are going to get the average height. Not exactly what you want. 

Being an optical sensor, sunlight and fog is going to be a problem. Mostly sunlight. Fog not so much. 

I'd seriously consider radar. A lot more expensive, but you will get an answer faster. 

but then I don't build a radar system, and it might have issues as well. I just don't know.


- john

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