Which sensor i should go with for designing Obstacle Detection Sensor?

[Akansha]

Hi,

I am designing Obstacle Detection Sensor for AGVs. I have following requirements:

• Ranging Distance : 5-8m
• Ranging Frequency: 30Hz
• FoV: 135 degree with multiple sensors

I have gone through Vl53L1X and Vl53L1CB sensor, i found that ranging distance of 8m is possible with Vl53L1CB sensor in Ranging Mode. Is it possible in indoor environment?

Along with this what will be output of Vl53L1CB sensor? Will that be distance of detected object?

What will be affect of ambient light on ranging distance?

Vl53L1CB GUI is accessible through F411RE Nucleo Board or not?

Please resolve my queries so that i can proceed further

Regards

Akansha Verma

[John E KVAM]

The VL53L1CB is the only thing that can do 8M. But it's going to take a really large object at that distance to be able to 'see' it.

Indoor is the only envionment where you have a chance. Sunlight really cuts down the ranging distance.

The sensor gives ranging distance, signal strength, ambient strenght and a ranging status.

You can by the P-nucleo-53L1A2 that has the F401RE on it. It's the only one that runs the Evaluation softare.

• john

[Akansha]

Thanks for replying!

What is the minimum size of obstacle it can detect at that ranging distance?

I need to detect obstacle of at least size 5 cm at that ranging distance.

Is that possible with this sensor?

Or there is trade off between ranging distance and obstacle size to be detected?

Please resolve this query too.

Regards

Akansha

[John E KVAM]

I always tell people you can 'see' a hand to 70 cm. After that, the distance at which you can successfully range depends on the size of the target.

You can detect people to about 3M - unless they are wearing cotton fleece which is amazingly non-reflective.

The light goes out in a cone of 27 degrees, and we need a certain amount of light to be reflected in order to successfully range.

As the light spreads and the target fills less and less of the field of view, we begin to have trouble.

If you want to range really far with a really small target, you are going to have to make that target amazingly reflective.

3M reflective tape works really well for this.

But the best advice I can give is to buy the EVAL kit for $56 dollars and give it a try in your application. It will quickly tell you if it will work in your application

P-Nucleo-53L1A2 is the eval kit for the VL53L1CB - the longest distance one we have.

[Akansha]

Thanks for Replying!

I got my queries resolved

Regards

Akansha

[Akansha]

Hi,

I have one more doubt about dimension of target which can be detected at a particular distance.

Like our requirement include detecting target of dimension (60 X 60)mm at the range of at least 3 m from the sensor.

Do this sensor will fulfill our requirement or not?

Please clear this query.

Regards

Akansha

[John E KVAM]

The answer is "it depends", or "maybe". But generally not.

However that's not very satisfying.

So I will explain.

The light goes out in a cone of 27 degrees.

And at 3 meters it's a circle who's diameter is about half the distance. (actually 0.44)

The illuminated area = 1.4 sqare meters - of which you have illuminated about 36 square cm.

So unless your target is very reflective indeed, you will not see it.

I try to publish that the sensor can see people to about 3M.

And I know that not very scientific. People come in all shapes and the clothing they wear makes an impact.

But it's a practical measure.

If you get to choose your target you can make it bright enough to see.

Aluminum foil would work.

3M reflective tape is pretty amazing stuff.

But I'm thinking you are going to need something more reflective than standard white paper to get your test to pass.

• john