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Very cool! Six years ago I worked on a mmWave (76-81GHz) imaging radar with a Rotman lens Tx and Rx. Designed as a LiDAR replacement, but we could see pipes in
by amirhirsch 3mo ago
Very cool! Six years ago I worked on a mmWave (76-81GHz) imaging radar with a Rotman lens Tx and Rx. Designed as a LiDAR replacement, but we could see pipes in walls, or detect concealed weapons at ~1km.
- GL26 3mo agoHow many tx and rx antennas did you have ? (I don’t know if it was clear, my stack was 57-64 GHz, 2TX , 3RX)
- amirhirsch 3mo ago32 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
- buildbot 3mo agoErr 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)
- amirhirsch 3mo agoIt 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...
- amirhirsch 3mo ago(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)
- Melatonic 3mo agoWhat project was that for ?! Sounds super cool
- mlmonkey 3mo agoDo you have a writeup about the project? I'd love to read more about it.
- Melatonic 3mo agoSuper 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 transmission as well.
- dylan604 3mo agoisn't mmWave the thing they use at the airports?
- Domenic_S 3mo agoYes 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!
- jamiek88 3mo agoMate this is genius! How have I not thought of mmWave detection. Rabbit hole activate!
- coredog64 3mo agoWaiting for an M413 motion detector to be commercially available.
- Melatonic 3mo agoBelieve they do use a good amount more power though (mainly only an issue for battery based devices)