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VL53L1X or other people flow sensor- minimum power and sensor choice

Tcodd.1
Associate II

I'm researching the usefulness of the VL53L1X for people flow detection in/out of a room. I know example given but I'm left with two questions:

A) Which of the SM ToF sensors in VL53 series might provide same capability as example?

B) Without experience and experimentation I'm unclear how low the power consumption would be for a door sensor based on VL53L1, for example, so I can determine battery life?

Also, what mode, settings, and sampling approach etc would ideally provide an interrupt driven continuous door sensing capability with minimum power consumption?

Thanks for your consideration.

1 ACCEPTED SOLUTION

Accepted Solutions
John E KVAM
ST Employee

power is always a problem.

the sensor uses 20mA while ranging, and a reasonable range takes 20ms.

So to range once 3 times per second you need 20mA *0.020seconds * 3 samples/sec = 1.2mA

So if you just wanted to detect slow moving things like a hand under a faucet 3 times per second is fine.

But to measure people through a door, you need to range enough to determine direction. And to do that you must range continuously.

I used the VL53L1X and created 2 zones. An inner and an outer. Then I ping-ponged between them using not only the range information, but the signal strength information and I was able to determine if the inner was hit before the outer indicating an exit or the other way around.

But to do it I had to range continuously. And that uses 20mA. So a battery is not going to work very well.

Sorry about that.

  • john

If this or any post solves your issue, please mark them as 'Accept as Solution' It really helps. And if you notice anything wrong do not hesitate to 'Report Inappropriate Content'. Someone will review it.

View solution in original post

3 REPLIES 3
John E KVAM
ST Employee

power is always a problem.

the sensor uses 20mA while ranging, and a reasonable range takes 20ms.

So to range once 3 times per second you need 20mA *0.020seconds * 3 samples/sec = 1.2mA

So if you just wanted to detect slow moving things like a hand under a faucet 3 times per second is fine.

But to measure people through a door, you need to range enough to determine direction. And to do that you must range continuously.

I used the VL53L1X and created 2 zones. An inner and an outer. Then I ping-ponged between them using not only the range information, but the signal strength information and I was able to determine if the inner was hit before the outer indicating an exit or the other way around.

But to do it I had to range continuously. And that uses 20mA. So a battery is not going to work very well.

Sorry about that.

  • john

If this or any post solves your issue, please mark them as 'Accept as Solution' It really helps. And if you notice anything wrong do not hesitate to 'Report Inappropriate Content'. Someone will review it.

john, I appreciate that you read my post and replied. In light of this information I will look at what my options are. Thanks

But, if you have any other ideas i might consider I would appreciate the input--there's a lot of technologies out and about that I might not be aware of. I need to detect flow of people (animals?) in/out of an entry way with minimal wiring. I have the wireless communication worked out, but the solution needs to operate off battery.

Thanks again.