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I built a mmWave material classification radar (2025)

gauthier-lechevalier.com

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Re: I built a mmWave material classification radar (2025)

#31

Post by Domenic_S »

dylan604 wrote: post #30
Melatonic wrote: post #27

Earlier quoted context omitted.

Super cool. Didn't even know mmWave was used for radar and imaging techniques! Isnt mmWave pretty similar (in theory) to short-ish range wireless directional antennas? What people used to call point to point "microwave" transmission? Crazy idea but could your mmWave radar hardware also be (not simultanouslyl) used to transmit data? No idea what a Rotman Lens is but I would imagine that maybe it could be useful for tr…

isn't mmWave the thing they use at the airports?

Yes it is!

I've been down the mmWave rabbit hole for the last 6 months, making sensors to put around the house to control automations for lights and so forth. They're pretty great.

For my use case the advantage over PIR is they do presence detection, so no more lights shutting off when you're sitting on the toilet.

Pretty amazing you can pick up basic mmWave sensors for a few bucks on amazon, and mate them to an esp32 board which is another couple bucks. It's so much fun as a hobby!

Re: I built a mmWave material classification radar (2025)

#32

Post by deepsun »

> I live in Europe, where asbestos is a huge and common pain across every country here. That stuff fills walls, and requires people to come at your place to tell you if you have asbestos contaminated materials in your building. If so, you might have been breathing poison since you were a kid.

Asbestos doesn't work like that. If you don't touch it, you're fine. You can live your whole life in asbestos building and be safe. You may even be worse off if you decide to get rid of it and start tearing down walls.

So it's good that it's banned, but if there's no reason to touch it, you're just making a tinfoil hat. There's more harm from the fear of it.

Re: I built a mmWave material classification radar (2025)

#34

Post by jamiek88 »

Domenic_S wrote: post #31
dylan604 wrote: post #30

Earlier quoted context omitted.

isn't mmWave the thing they use at the airports?

Yes it is! I've been down the mmWave rabbit hole for the last 6 months, making sensors to put around the house to control automations for lights and so forth. They're pretty great. For my use case the advantage over PIR is they do presence detection, so no more lights shutting off when you're sitting on the toilet. Pretty amazing you can pick up basic mmWave sensors for a few bucks on amazon, and mate them to an esp3…

Mate this is genius! How have I not thought of mmWave detection. Rabbit hole activate!

Re: I built a mmWave material classification radar (2025)

#35

Post by coredog64 »

Domenic_S wrote: post #31
dylan604 wrote: post #30

Earlier quoted context omitted.

isn't mmWave the thing they use at the airports?

Yes it is! I've been down the mmWave rabbit hole for the last 6 months, making sensors to put around the house to control automations for lights and so forth. They're pretty great. For my use case the advantage over PIR is they do presence detection, so no more lights shutting off when you're sitting on the toilet. Pretty amazing you can pick up basic mmWave sensors for a few bucks on amazon, and mate them to an esp3…

Waiting for an M413 motion detector to be commercially available.

Re: I built a mmWave material classification radar (2025)

#36

Post by jschveibinz »

jcims wrote: post #19

Very cool idea. I'm sure this can be annoying when people do this, but I can't help myself lol. I wonder if you could operate in a different modality and find discontinuities in material properties rather than use it as a classifier. For some reason skin cancer detection popped into my head, but general purpose inspection/detection cases for any discontinuities might be pretty helpful. Depending on the resolution/siz…

imaging spectroscopy is a potential solution--it's been studied for over 30 years.

Re: I built a mmWave material classification radar (2025)

#37

Post by DrewADesign »

deepsun wrote: post #32

> I live in Europe, where asbestos is a huge and common pain across every country here. That stuff fills walls, and requires people to come at your place to tell you if you have asbestos contaminated materials in your building. If so, you might have been breathing poison since you were a kid. Asbestos doesn't work like that. If you don't touch it, you're fine. You can live your whole life in asbestos building and be…

It’s not that straightforward. Asbestos comes in many forms with varying friability. Mixed into linoleum floor tiles? Probably not a big deal. Mixed into wall plaster in a poorly maintained rental unit? A hell of a lot riskier. And a lot of the buildings that have asbestos-wrapped pipes, for example, have cramped utility crawl spaces and basements that can make it difficult to avoid. If you’ve got asbestos hidden behind a stable and well-maintained wall, or on utility lines that are easily avoided, then whatever. That’s frequently not the case, however.

Re: I built a mmWave material classification radar (2025)

#38

Post by buildbot »

amirhirsch wrote: post #7
GL26 wrote: post #4

Earlier quoted context omitted.

How many tx and rx antennas did you have ? (I don’t know if it was clear, my stack was 57-64 GHz, 2TX , 3RX)

32 port Tx (vertical pancake beams) x 16 port Rx (horizontal pancake), something like 60 by 30 degrees. the entire thing used FPGA transceivers as one-bit DAC/ADC, Complementary Golay Code waveforms with one-bit correlation in the FPGAs (two VCU128s) -- digital logic was essentially the same as a binarized neural network, I squeezed a ton of popcnt performance out of those chips using both DSPs and LUTs

Err holy shit that’s quite the array and FPGA processing backend. I assume the purpose of the system is secret?

(VCU128s are relatively large, HBM equipped FPGAs for people not aware)

Re: I built a mmWave material classification radar (2025)

#39

Post by amirhirsch »

buildbot wrote: post #38
amirhirsch wrote: post #7

Earlier quoted context omitted.

32 port Tx (vertical pancake beams) x 16 port Rx (horizontal pancake), something like 60 by 30 degrees. the entire thing used FPGA transceivers as one-bit DAC/ADC, Complementary Golay Code waveforms with one-bit correlation in the FPGAs (two VCU128s) -- digital logic was essentially the same as a binarized neural network, I squeezed a ton of popcnt performance out of those chips using both DSPs and LUTs

Err holy shit that’s quite the array and FPGA processing backend. I assume the purpose of the system is secret? (VCU128s are relatively large, HBM equipped FPGAs for people not aware)

It was designed for automotive as a replacement for LiDAR, also useful for finding metal FOD on runways, or concealed weapons and I suppose also liquids on travelers walking in an airport...

Re: I built a mmWave material classification radar (2025)

#40

Post by amirhirsch »

buildbot wrote: post #38
amirhirsch wrote: post #7

Earlier quoted context omitted.

32 port Tx (vertical pancake beams) x 16 port Rx (horizontal pancake), something like 60 by 30 degrees. the entire thing used FPGA transceivers as one-bit DAC/ADC, Complementary Golay Code waveforms with one-bit correlation in the FPGAs (two VCU128s) -- digital logic was essentially the same as a binarized neural network, I squeezed a ton of popcnt performance out of those chips using both DSPs and LUTs

Err holy shit that’s quite the array and FPGA processing backend. I assume the purpose of the system is secret? (VCU128s are relatively large, HBM equipped FPGAs for people not aware)

(Linked VCU128 digital radar was cool but even cooler is using them as digital array beamformers and sending RDMA over fiber into a quad A100s nvlinked to do the whole radar DSP pipeline)
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