Live data from Hacker News

Building an occupancy sensor with a $5 ESP32 and a serverless DB

matthew.science

211–220 of 221 posts

Re: Building an occupancy sensor with a $5 ESP32 and a serverless DB

#211
post #130

Ultra wide band can be used to detect tiny movements of humans in a room. It can detect a finger twitching from several meters away. https://www.eenewseurope.com/en/uwb-human-sensor-uses-impuls...

Aqara makes a mmWave presence sensor https://www.aqara.com/us/product/presence-sensor-fp2

That's even better!

Re: Building an occupancy sensor with a $5 ESP32 and a serverless DB

#212

Earlier quoted context omitted.

The hash map was definitely not robust enough, that’s why I ultimately switched back to the default behavior and increased the memory available on the board! Also, I am a Rust fanatic. I do nearly everything in it! I gave a talk on it at our last hackathon! I even wear a Rust t-shirt regularly! So rest assured I will be exploring my options with Rust. I would love to get rid of my dependence on Arduino. But C++ was e…

Is it possible to program this device without the espresso SDK and the arduino stuff? Whether I'll use C++ or Rust for my next project depends on which one I can first get working on this board with the standard toolchain (GCC and Rustc respectively)

https://esp-rs.github.io/book/

Yes

Re: Building an occupancy sensor with a $5 ESP32 and a serverless DB

#213

Earlier quoted context omitted.

If you want to get really, really spicy, use three devices/antennas and you can roughly track in three-dimensional space.

Wouldn’t three dimensional tracking need four antennas?

Three appropriately spaced antennas will give you azimuth and elevation of a ray to the transmitter, but not distance.

But using two of the above in different, known locations would allow you to compute the intersection to a 3D location.

Re: Building an occupancy sensor with a $5 ESP32 and a serverless DB

#214

Earlier quoted context omitted.

I wonder what the "rules" are for things like tracking beacons. They're being broadcast, and they're almost certainly collected without consent everywhere we go. I happen to live at a junction where my home is regularly surrounded by large numbers of Bluetooth devices; I had considered setting up a BLE tracker purely for "fun" to see what I could collect and discern from the data. For example, one thing I'm certain o…

Depends on local laws and jurisdiction. US famously has no communication secrecy laws, some countries states broadcast is free to listen, etc. But I think the point made in GP is tracking people, although indirectly, could qualify as `human subject research`, the same technical category as Stanford prison experiment, MKULTRA project, standard website A/B testing, etc. I don't think it's going to be a problem per se,…

Ah interesting point I hadn't thought about/considered.

Re: Building an occupancy sensor with a $5 ESP32 and a serverless DB

#215

Earlier quoted context omitted.

I wonder what the "rules" are for things like tracking beacons. They're being broadcast, and they're almost certainly collected without consent everywhere we go. I happen to live at a junction where my home is regularly surrounded by large numbers of Bluetooth devices; I had considered setting up a BLE tracker purely for "fun" to see what I could collect and discern from the data. For example, one thing I'm certain o…

I don't understand your last paragraph. Do you mean it correlates to lots of internal combustion engines nearby (e.g. pollution)? How else would this possibly affect your air quality?

You understood perfectly.

Re: Building an occupancy sensor with a $5 ESP32 and a serverless DB

#216

Earlier quoted context omitted.

Is it possible to program this device without the espresso SDK and the arduino stuff? Whether I'll use C++ or Rust for my next project depends on which one I can first get working on this board with the standard toolchain (GCC and Rustc respectively)

https://esp-rs.github.io/book/ Yes

https://esp-rs.github.io/book/installation/riscv-and-xtensa....

"What espup Installs

...

    Espressif Rust fork with support for Espressif targets
...

    LLVM fork with support for Xtensa targets"


 :( ?

Re: Building an occupancy sensor with a $5 ESP32 and a serverless DB

#217

Earlier quoted context omitted.

It's funny, but it's also true. There are definitely times when I'm more "in the mood" for projects; In the winter particularly, I work more on my electronic projects, and do more gaming (my Gaming "season" just started again last week). Of course the dramatic shift from "what do I feel like doing today" to "what am I in the mood for / have time for this season" has a lot to do with me being older and having children…

I can relate a lot. Having the momentum on your side is the main force that pushes such a project forward. Especially if you have family duties that ususally consume most of your free time. As long as children are smaller even things like scheduling time for your projects don't work very well. Usually because unexpected things happen that need to be handled. Sickness, children waking up early or taking longer to go t…

Absolutely, I just have to see how it goes on the day, if they get to sleep easily and on time I have a couple of hours maybe after doing the chores, but more often than not I'll come and sit down at my desk and just think; I'm too tired, or not in the mood for this, and I decided recently that that's fine.

I was talking to my wife about this over dinner the other day. At one point, early after the kids came along, this really bothered me, not being able to do my projects/hobbies, but I came to a realisation, once things had settled down a bit.

Even though I _want_ to do these things, I want to spend time with my kids, my family, more, and these other things are inconsequential whether they happen or not.

I'm never likely to look back and think "I regret not building X with an ESP32", and I don't intend to look back and wish I'd spent more time with my kids, they grow up quick.

Don't get me wrong, I still find time for hobbies, and little projects; much less so than I did, but now I just find I need/want to spend less of my time building/tinkering with things that no longer have the same value to me that they used to, my brain is slowly catching up with that realisation.

Re: Building an occupancy sensor with a $5 ESP32 and a serverless DB

#218

Earlier quoted context omitted.

https://esp-rs.github.io/book/ Yes

https://esp-rs.github.io/book/installation/riscv-and-xtensa.... "What espup Installs ... Espressif Rust fork with support for Espressif targets ... LLVM fork with support for Xtensa targets" :( ?

Yeah risc-v is in the rust supported tiers but xtensa isn’t. I haven’t dug deeply into whether the riscv esp32c3 boards still use some forked rust etc, though, but in theory shouldn’t as it’s a tier 2 architecture.

That said, for my use, it’s entirely transparent this is happening under the covers. Things work as they should in your ESP32 cargo projects as don’t interfere with other targets, and I’ve not found any weird edges. I do however use the c3 boards.

Re: Building an occupancy sensor with a $5 ESP32 and a serverless DB

#219
post #119

Outstanding write-up! We actually built a business based on this technology (occuspace.io) and have had to address almost all the questions that you brought up. To answer some of them here: Q: How accurate is BLE beacon count, as a proxy for occupancy? A: It's very highly correlated but different dining locations, classrooms and library floors have very different correlation factors. Consider using other, perhaps mor…

FWIW, Meraki gives you this as well as part of their cloud management of their network. They might be able to do a lot more if they track wifi, wifi macs, and vision and tie it together.

Just letting you know of one of your potential competitors.

Re: Building an occupancy sensor with a $5 ESP32 and a serverless DB

#220

Earlier quoted context omitted.

I can relate a lot. Having the momentum on your side is the main force that pushes such a project forward. Especially if you have family duties that ususally consume most of your free time. As long as children are smaller even things like scheduling time for your projects don't work very well. Usually because unexpected things happen that need to be handled. Sickness, children waking up early or taking longer to go t…

Absolutely, I just have to see how it goes on the day, if they get to sleep easily and on time I have a couple of hours maybe after doing the chores, but more often than not I'll come and sit down at my desk and just think; I'm too tired, or not in the mood for this, and I decided recently that that's fine. I was talking to my wife about this over dinner the other day. At one point, early after the kids came along, t…

Yes, it took me some time to adapt to the fact that there is much less time for your own projects. Now I'm totally fine with that. The good thing is, the kids grow older and suddenly time windows become available again.

I once read that about 80% of the whole time you spent together with your children is spent before they are 10 years old. So your are right when you say your want to spent the time with your children now.

Post reply on HN