I am developing a solution for water level with VL53L1CX and now I've seen there is a new version, VL53L1CB. Wich has the best performance in long range distance for water? Can I just switch IC without changing my PCB and firmware? Thank you.

[John E KVAM]

There are a few issues when measuring the depth of water.

The first is that you want to be perpendicular to the water. Photons will reflect off the surface if the hit it at very near 90 degrees.

The other thing is that the VL53L1X's Field of View is working against you. You really want a more narrow FoV. Especially if your tank is small.

I might suggest the brand new VL53L4CD. It is footprint identical to the L1X, and it's cheaper too.

If you need longer distance than the specified 1.3M, you can either use the L4CD with the L1X software, or you can move to the VL53L4CX. This sensor has the identical code to the L1CX and a range of 6M.

All the chips I mention have the same footprint, so any investment in hardware is preserved. And code of the L1X, the L4CD are nearly identical. The Historgram code for the L1CX and the L4CX are nearly identical.

Choose the sensor by how far you must range. If you can, use the L4 in preference to the L1's due to the Field of View.

(I must note however that although all the distribution channels are ready for the VL53L4 sensors, they still don't show stock. This should be cleared up in the coming days.)

• john

[GOnzi.1]

Hello John and thank you very much for the fast response. I've seen you in the latest webinar about the Ultra Lite Driver.

The thing is we need right now to decide wich to buy(100-500 parts for proof of concept) and I already know exactly how VL53L1CX works. I was about to buy it when I saw possibility for VL53L1CB. What I need to know for sure is if I change from CX to CB, is there a chance of worst performance from CB in any case? My application involves not only water but Diesel and all kinds of stuf we had good results. Another thing is the cover window that was developed and tested for VL53L1CX. Will it work the same for VL53L1CB?

Best regards,

Gabriel

[John E KVAM]

The L1CB is an L1CX that has been tested to run the more demanding Histogram software.

What you might want to do is buy the the L1CB for your proof of concept. Run it with the L1CX software as it is completely backward compatible. It it works with the CX software, then go into production with the CX. But if you find you need the extra range the CB affords, then you can stick with that.

Physically these chips are identical. So the coverglass will work with both.

As an experiment, you might want to try running the CB software on your CX. It is not guaranteed to work reliably, but for a quick Proof of Concept, it will work fine. Just don't go into production like this.

Good luck.

= john

[GOnzi.1]

Sorry to bother again, but I didn't get it yet. I will try to break it down in a few more specific questions:

1 - You are saying that the firmware from a L1CX prototype will work properly with L1CB?

2 - Does L1CB performs better than L1CX in any distance measurement scenario in full 4 meters range? Or there is a application where L1CX is better suited?

Thank you.

[John E KVAM]

1 - yes. The L1CB is a super-set of the L1X. You could use L1CB to prototype both sensors just by changing the software. Then pick the one you want. L1X code is simple. L1CB ranges longer and the code is more complex.

2 - The L1CB ranges farther. Or it can range the same distance with fewer SPADs. This means you could have a more narrow field of view with the L1CB and still range the same distance.

[FBass.1]

Hi @John E KVAM 

I have been reading up on you posts with regards to the VL53L1 and VL53L4 sensors.  Currently I am testing the VL53L1CB sensor in a water tank ranging up to 2.5m.  For the final product ideally I would like to range up to 6m.  I am finding some anomalies during dusk and dawn, refer to the graph attached.

The water level in the tank is constant now with no movement, so there should not be the deviations you can see on the graph.  We have found a way to deal with condensation so the lend is remaining dry.  Do you think the VL53L4 will perform better in our use case?

Regards,

Friedl.

[John E KVAM]

Water is a pretty special case. There are very few photons that get refected. And so getting a good reliable water distance above a couple of meters is going to be a real trick.

If you have 56 dollars, buy the VL53L4CX evaluation kit and try it. the L0, L1, L3 and L4 sensors all have the same footprint, so electrically it's easy to swap. 

It is my claim the VL53L1CX would be your best bet. Although the L1CB with it's optical elements might be better. 

the L4CX eval kit part number is P-nucleo-53L4a2. 

I'd give that a try.

- john