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Inside a $1 radar motion sensor

10maurycy10.github.io

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Re: Inside a $1 radar motion sensor

#31

Post by mianos »

amelius wrote: post #29
stavros wrote: post #26

Earlier quoted context omitted.

Get the B variant, you can configure it over Bluetooth from your phone. Otherwise it's a huge hassle. That said, it doesn't work very well for me when sitting still 4-5m away, it thinks I've left.

These radars are designed to detect motion, not someone sitting still.

Wrong, most of these radars are 24Ghz and specifically designed to detect body micro movements. They specifically give both human 'occupancy' and dynamic ranging information.

I wrote low level drivers for the ESP32 for all the ones I could buy and have tested all of them. The only one that does not try to give a human occupancy position is the car speed sensor.

The ld2450 can track three people at once.

https://github.com/mianos/hk-heltec-radar/tree/main/src

Re: Inside a $1 radar motion sensor

#32

Post by [deleted] »

metadat wrote: post #5
wisty wrote: post #3

Reminds me of the HB100 teardown, but at least this one has an IC to make it more soothing that I don't really understand how it all works. https://www.allaboutcircuits.com/news/teardown-tuesday-hb100...

Too fantastic not to submit: https://news.ycombinator.com/item?id=40834960

[deleted]

Re: Inside a $1 radar motion sensor

#33

Post by withinboredom »

amelius wrote: post #27
transpute wrote: post #2

Through-wall 2.4Ghz Wi-Fi CSI radar can be done with $20 ESP32 boards, https://github.com/Marsrocky/Awesome-WiFi-CSI-Sensing & https://www.cnx-software.com/2022/08/08/esp-wifi-csi-detects... > Espressif claims it can also capture subtle movements caused by small movements such as breathing and chewing of people or animals in a static environment.. works with all ESP32 series microcontrollers including ESP32, ESP32-S2…

These $1 boards also work through walls (I tried this).

I always go through walls.

— kool aid man

Re: Inside a $1 radar motion sensor

#34

Post by LoganDark »

stavros wrote: post #24
tstrimple wrote: post #16

Earlier quoted context omitted.

Strangely enough I've heard far more people make this "joke" than actual vegans speaking up. Even when living in LA.

The issue with this joke is that it's 100% confirmation bias. You know that all the vegans tell you they're vegan because you don't know about the ones that didn't.

I think it's also survivorship bias. All the people who tell you they're vegan being vegan does not mean that all the people who are vegan will tell you they're vegan, just like all the people who won the lottery probably having bought lots of tickets does not mean that buying lots of tickets will win you the lottery.

Re: Inside a $1 radar motion sensor

#35

Post by the_third_wave »

lopis wrote: post #12
throwup238 wrote: post #7

Earlier quoted context omitted.

> chewing of people or animals The ESP32 can detect the difference between a cannibal and a vegan? That's impressive.

How can you tell someone is a vegan? Don't worry, this 1$ radar motion sensor can tell you.

Come on, that's simple, just use voice recognition since the vegan won't stop telling the sensor about it.

Re: Inside a $1 radar motion sensor

#36

Post by squarefoot »

stavros wrote: post #23
t0mas88 wrote: post #18

Earlier quoted context omitted.

Wifi sensing is interesting, but you can combine a $3 ESP chip with one of these for a much easier project at lower cost: https://www.dfrobot.com/product-2795.html I use those for presence detection in my house. 3D print a small case and for < $20 you have highly accurate presence detection that also works when sitting still. Ideal for automatic light and climate control.

My problem with similar sensors is that they don't work very well if you're sitting still around 3m away. Maybe my sensor isn't great, but when I'm sitting still at the computer, it frequently thinks I'm not there any more, which ruins any benefit.

Pairing them with PIR detection should help to also detect stationary warm objects.

Re: Inside a $1 radar motion sensor

#37

Post by stavros »

mianos wrote: post #31
amelius wrote: post #29

Earlier quoted context omitted.

These radars are designed to detect motion, not someone sitting still.

Wrong, most of these radars are 24Ghz and specifically designed to detect body micro movements. They specifically give both human 'occupancy' and dynamic ranging information. I wrote low level drivers for the ESP32 for all the ones I could buy and have tested all of them. The only one that does not try to give a human occupancy position is the car speed sensor. The ld2450 can track three people at once. https://githu…

This sounds very interesting, how do your drivers work? I'd love to try them out, but there's no documentation. I've made a sensor board with various sensors, I could really use some occupancy detection improvements on the LD2450B.

Re: Inside a $1 radar motion sensor

#38

Post by stavros »

squarefoot wrote: post #36
stavros wrote: post #23

Earlier quoted context omitted.

My problem with similar sensors is that they don't work very well if you're sitting still around 3m away. Maybe my sensor isn't great, but when I'm sitting still at the computer, it frequently thinks I'm not there any more, which ruins any benefit.

Pairing them with PIR detection should help to also detect stationary warm objects.

I did pair them, unfortunately PIR sensors are even worse at detecting stationary objects (less sensitive to body micromovements).

Re: Inside a $1 radar motion sensor

#39

Post by stavros »

LoganDark wrote: post #34
stavros wrote: post #24

Earlier quoted context omitted.

The issue with this joke is that it's 100% confirmation bias. You know that all the vegans tell you they're vegan because you don't know about the ones that didn't.

I think it's also survivorship bias. All the people who tell you they're vegan being vegan does not mean that all the people who are vegan will tell you they're vegan, just like all the people who won the lottery probably having bought lots of tickets does not mean that buying lots of tickets will win you the lottery.

That's what I meant, maybe I used the wrong bias name.
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