VL6180 register setup for use with cover filter

[GMcPh.1]

I am using the standard VL6180 Breakout Board from ST connected to a pyboard running micropython.

For my application I need a range at least up to 200mm using multiple reflective surfaces from reflective to not so reflective. I have managed to get the cover filters as specified in the application notes. The one I am using is the IR-T078C0-CC3L-A066-C from hornix.

In this setup, I get a working range up to 200mm with a reflective surface (light coloured paper) but much lower range for a dark surface.

I have not found a specific application note dedicated to the VL6180, just the VL6180X and have used that as a starting point to set up the registers. (AN4545 - VL6180X basic ranging application note). Is there a specific app note for the VL6180 I should rather use?

Similarly, does ST have a pre-defined set of values for the Hornix cover filters they recommend. Any help in setting up the registers correctly to maximise ranging over a range of surfaces would be much appreciated.

Thanks in advance

[John E KVAM]

One will always be able to range farther using a more reflective target. That's just physics. But 20 cm is not very far.

However at 20cm the diameter of base of the cone of illumation is 10cm. Is your target at least that large? Smaller, less reflective targets are by diffination a worst case.

if not, it would explain your issue.

Did you get good ranging without the coverglass?

That coverglass is pretty transparent. 95% I think.

So you are not losing much light to the glass.

It should not be much worse with the glass than without it.

Run some tests and tabulate the data. Find the max distance of your typical targets. Include their sizes.

I will attempt to duplicate your experiment.

Is it possible that ambient light is an issue? Bright sunlight - or even some sunlight can affect your sensor's performace.

Can you try the experiment in the dark - or under LED lighting?

If you find you just cannot make it work then you are going to have to move to the VL53L0X.

That sensor is not pin-for-pin compatable, but will fix your issues.

• john

[GMcPh.1]

Thanks John,

I have definitely run into the problem of the target not being large enough in the actual application. As such we have reverted to the older mechanical design which places the targets at 10cm.

I have bought both the VL53L0X and VL53L1X satellites to test with once I have the time. Because the FOV is still 25 degrees, I'm not sure the VL53L0X will work either. I'll need to look to see if I can easily use ROI feature on the VL53L1X.