VL53L4ED - How does it work in dusty and industrial environments.

[sherwood9]

Hi my name is Kevan Sherwood with Rayhawk Technologies, we develop an autonomous solution for opening and closing rails cars during the loading process. We have a toolhead that scans the gantry for a railcar to be opened and it then finds the latches opens them and opens the lid and moves on to the next. There are 2 feet on the bottom that do the opening and closing. We are testing with one of these VCSEL sensors (VL53L4ED) on the breakout boards to track the position of the feet on our tool when it is performing an opening and closing action. The goal is to see based on the foot position where in the process it is going wrong and have a data representation of what a good action looks like compared to a failed action.

We have the sensor mounted at the end of the tool bar and it is pointed at a rod that moves with the feet. So it will measure the distance traveled when the feet are pressed. The distance being covered is 350mm total.

Our main concern is dust and dust buildup on the sensor, since our units are going to be installed at grain elevators and mine loading stations.

Please if you could give some answers to how to reliable these sensors are and how they standup over time. That would be great.

If you want to see exactly how our machine works check out he home page and watch the animation video link on the home page at the rayhawk website online. It shows exactly how our solution works and will give you an idea of what the feet look like.

Thanks,

Kevan Sherwood

[John E KVAM · Accepted solution]

The first thing that should be clear - you cannot see through a brick. So if it gets that dirty, you are going to have to clean it. 

That being said, one can buy or make a coverglass that completely fixes the issues until you just get too dirty. 

You can buy a coverglass from 閎喬光學 – Hornix Optical Technology - www.hornix.com.tw/en/home.

What you are looking for is a glass that fits tight onto the sensor and does not allow any light from the transmit side to get into the receive side without hitting your target. To do this you need two pieces of optical glass with an opaque barrier between them. 

I have a video on the subject:

VL53L1X: Calibration-Free Dirty Environment Cover Glass Solution - YouTube

The idea works well on all our parts. And there is a cover for the VL53L4 versions.

For your distances you will have few problems until that glass gets really bad. 

But I'd test it yourself. Buy the VL53L4CD eval kit (Same kit for the ED) P-Nucleo-53L4A1 and get the coverglass from Hornix. Start ranging. I sprinkled coffee creamer on the glass to simulate dust. As the dust gets thick the distance at which you can range goes down, but you won't get a wrong answer.