People Counting

[kent-williams]

Thanks for sharing your code for this new sensor!

How are you planning on deciphering the direction the person is moving to people count? I have done this in the past with a single grid-based PIR or thermal sensor, but it's not obvious how that can be done with a single one of these sensors? Are you planning on mounting this perpendicular to the doorway and leveraging two of them to know which one activates before or after the other?

[kriswiner]

"Are you planning on mounting this https://github.com/kriswiner/STHS34PF80/issues/1#issuecomment-1670457409 perpendicular to the doorway and leveraging two of them to know which one activates before or after the other?"

Yes, I have done this with the Calipile, that is used two of them and compared interrupt times to determine ingress or egress. This works very well, and I expect it to work well for the STHS34PF80 (I will know this week). The challenge here is not functionality but BOM cost and power usage. Detecting direction of travel cannot be done with only a single PIR sensor uless one were to use something like the Grideye (AMG8833 https://www.tindie.com/products/onehorse/grid-eye-8-x-8-ir-array/) sensor, which is actually 64 separate sensors, so expensive and a power hog...

On Tue, Aug 8, 2023 at 5:24 PM Kent Williams @.***> wrote:

Thanks for sharing your code for this new sensor!

How are you planning on deciphering the direction the person is moving to people count? I have done this in the past with a single grid-based PIR or thermal sensor, but it's not obvious how that can be done with a single one of these sensors? Are you planning on mounting this https://github.com/kriswiner/STHS34PF80/issues/1#issuecomment-1670457409 perpendicular to the doorway and leveraging two of them to know which one activates before or after the other?

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[kent-williams]

That's encouraging to hear! I built something very similar to this several years ago but used the AK9750 sensor, which has a quad PIR array and was able to decipher direction quite well. The only issue was that it was quite susceptible to outside light shining in a room.

[kriswiner]

I tested the AK9750 but its range wasn't that large. Its presence detection algorithm was hard for me to understand or use properly. Typical AK.

Two AK9754 single-pixel IR sensors worked quite well but again, the range was limited to ~10 cm or so and besides, this sensor is obsolete now. Too bad because it was super cheap and very low power.

The Calipile worked well, and we had a few startups testing it. In the end, the temperature drift was a killer for the low-power (i.e., battery lifetime) requirement.

The internal temperature compensation of the STHS34PF80 should avoid the need for frequent threshold recalibration and the internal presence detection ASIC seems capable of people detection without manual threshold setting. So overall, it looks like ST might have gotten it right for this application.

Now that I have a prototype design it should be a simple matter of testing.

What is your interest in this kind of device?

I am looking for marketing partners...

On Tue, Aug 8, 2023 at 5:39 PM Kent Williams @.***> wrote:

That's encouraging to hear! I built something very similar to this several years ago but used the AK9750 sensor https://datasheetspdf.com/pdf-file/1028134/AKM/AK9750/1, which has a quad PIR array and was able to decipher direction quite well. The only issue was that it was quite susceptible to outside light shining in a room.

[image: image] https://user-images.githubusercontent.com/479648/259265293-7fc50130-6ed9-4219-b4a3-9cda32e4a964.png

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[kent-williams]

It's definitely a shame all the AK detection sensors are obsolete, they did work great for some applications.

Looking forward to playing with the STHS34PF80, I've been waiting for something like it for a long time.

My interests are just exploratory for now. Will you be putting your board up for sale?

[kriswiner]

Maybe the breakout...depends on interest.

On Tue, Aug 8, 2023 at 6:15 PM Kent Williams @.***> wrote:

It's definitely a shame all the AK detection sensors are obsolete, they did work great for some applications.

Looking forward to playing with the STHS34PF80, I've been waiting for something like it for a long time.

My interests are just exploratory for now. Will you be putting your board up for sale?

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[kent-williams]

Appreciate the responses!