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vl53l1x with no target detected and a valid measurement. what to expect?

jaachaparro
Associate II

Hello.

I am working with a vl53l1x sensor and i need to know if this sensor report a distance when the target is not detected and the measurement is valid, like the vl53l3cx sensor that report back 8191. Does this sensor report the same number or other number in this condition? Or does not report back anything when this happen?

1 ACCEPTED SOLUTION

Accepted Solutions
John E KVAM
ST Employee

You are missing a trick - One must check the Range Status register to see what the sensor is telling you. 

There are several warnings and errors that can fill you in as to why you should question your result.

When there is no target, we have to return something. Putting in a zero in the range register might indicate a close target, so we chose 8192 minus the status register. That's why you got the 8191. It's a number not possible to get from our chip - unless there was an issue.

The trick is to understand what the sensor is telling you, then decide if you want to keep the data.

Low signal means the distance might be a bunch off - due to a lack of photons. 

But you can keep the number if you have reason to believe it's right, or if you don't need a lot of accuracy.

Similarly you might decide a high sigma is acceptable - or not. It means the photon return times are not well correlated - due to motion or something.

Check the Range Status - and if it's bad, toss out the data range.

 


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

You are missing a trick - One must check the Range Status register to see what the sensor is telling you. 

There are several warnings and errors that can fill you in as to why you should question your result.

When there is no target, we have to return something. Putting in a zero in the range register might indicate a close target, so we chose 8192 minus the status register. That's why you got the 8191. It's a number not possible to get from our chip - unless there was an issue.

The trick is to understand what the sensor is telling you, then decide if you want to keep the data.

Low signal means the distance might be a bunch off - due to a lack of photons. 

But you can keep the number if you have reason to believe it's right, or if you don't need a lot of accuracy.

Similarly you might decide a high sigma is acceptable - or not. It means the photon return times are not well correlated - due to motion or something.

Check the Range Status - and if it's bad, toss out the data range.

 


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.