Can we measure the frequency of the beam (VL53L0X) ?

[SSilv]

Hello Guys,

I hope you all are doing well.

I am working on a project that with the VL53L0X ToF Sensor and ESP modules.

The sensor works great and i am trying to get deeper into its reads because what i need.

I am trying to build a frequency meter using the VL53L0X, to take small vibrations of a surface (starting from 50Hz). I have been trying to read millimeters and put them in a array and making the maths to calculate the frequency, but no luck.

Is there any way to read the raw data of the receiver (SPAD) ? Maybe starting a countinous read for 1000ms and getting each signal read and its strenght… i dont know.

Or maybe if there is a way to measure the travel time of the signal or the time spent to the signal get from the emitter to the receiver, i could put it in a array to calculate frequency.

Normal frequency calc libs are not working on the ESP module because most of them require AVR that is not supported on ESP modules.

Would you guys be able to help me to achieve this or how to get the proper information of the sensor?

Thank you!

[John E KVAM · Accepted solution]

I don't think that is going to work. At the microscopic level, the sensor sends out maybe a million pulses of light per 30ms range. We spend a great deal of time averaging all the returns. This tends to smooth out the data you would be looking for.

And unfortunately you only get the averaged answer, not the raw data.

But watch for an ST announcement in the next month or two. We might have something that could help you. Sorry I cannot say more.

• john

[PRemy.1]

Dear John,

can you now share more about this "ST announcement". I would also be interested in the raw data directly out of the SPADs.

Thanks a lot.

Patrick

[John E KVAM]

​Go to the ST web site and search for the VL53L3. This new senor enables a 'histogram' technology where the raw data is sent to the host. Then the host can run a function that determines the range. But if you are willing to dig in there you can get to the raw histogram data. This does have a down-side. Clearly the host cannot be asleep while the range is being done - (autonomous mode), but not everyone needs that.

The datasheet is now published, but I'm not sure if the code is up yet. Might be a few days.

[PRemy.1]

Sounds very promising. The driver code does not seem to be available yet. Do you know where I will be able to find the first samples ?

Thanks

[John E KVAM]

The application library should be available this week. Let's give them until the end of the month.

• XCUBE example code will be completely ready by the end of March
• Demo Software - GUI will be completely ready second week of March.
• The Evaluation Kit is our real problem.  Lead time is too long.
• So we are getting there, and I'm sorry it's not faster.

First samples should be available from Mouser, Digikey, Arrow Avent and FutureElectronics at the same time, but I cannot say more than 'soon'.

[PRemy.1]

Also, I was wondering if there was any way of flashing a different firmware to the MCU of a VL53L0 or VL53L1, in order to have it report the raw data.

[John E KVAM]

​There is no user programmable memory in the sensors. But what you are asking for is exactly what we did with the VL53L3. We took the body of the VL53L0 and changed the programming of the MCU inside to collect the histogram data and send it to the host.

As for the VL53L1 histogram version, that's coming too, but I'm not sure when.