2 ms·

> Is this even legal? I live in the USA. IANAL, not even remotely, but I have some amount of familiarity with this stuff. Don't take me at my word, though. Get

> Is this even legal? I live in the USA. IANAL, not even remotely, but I have some amount of familiarity with this stuff. Don't take me at my word, though. Get expert advice instead. FCC rules absolutely apply here, and the FCC has explicit guidance for radar transmitters (https://docs.fcc.gov/public/attachments/DA-96-2040A1.pdf https://docs.fcc.gov/public/attachments/DA-96-2040A1.pdf). But which specific laws apply depends on a lot of things, such as what frequencies you're using. The laws are a lot more lenient if you aren't selling the thing you make, but they still exist. In general, they boil down to "you can't cause interference with licensed transmitters" and "you can't use more than a weak signal without a license". If I were doing a project like this, I'd probably look very hard at non-radio solutions, such as perhaps laser ranging, where there isn't much legal risk.

compressedgas 2y ago
See https://en.wikipedia.org/wiki/Lidar_traffic_enforcement https://en.wikipedia.org/wiki/Lidar_traffic_enforcement
- solardev 2y ago
  For tracking moving things from a stationary point, would you need some sort of "turret" that can track & aim the lidar? Or is there some equivalent of AESA in the lidar world? Edit: Apparently yes? Optical phased array lidars (https://lidarmag.com/2021/08/18/why-optical-phased-array-is-the-future-of-lidar-for-autonomous-vehicles/ https://lidarmag.com/2021/08/18/why-optical-phased-array-is-... or https://www.youtube.com/watch?v=5gml2tDogDI https://www.youtube.com/watch?v=5gml2tDogDI)
solardev 2y ago
You don't need to make your own radar and go through the FCC licensing on your own, though. There are commercially made hobbyist modules like https://www.digikey.com/en/products/detail/st-engineering-urban-solutions/HB100/24762149 https://www.digikey.com/en/products/detail/st-engineering-ur... that are already licensed: https://fcc.report/FCC-ID/VECHB100 https://fcc.report/FCC-ID/VECHB100
- jvanderbot 2y ago
  It's difficult to tell from the three page datasheet what effective range I would get. But that's a starting point at least.
  - solardev 2y ago
    As other posters mentioned, you would probably quickly run into FCC issues trying to scale up the radar to something powerful enough to reach across a lake. Probably one of the other solutions (LIDAR, machine vision in the visible, etc.) would be better for that? Or if it doesn't have to be all the time, maybe just hover a drone above them and record downwards?
    - jvanderbot 2y ago
      "Just hover a drone over them and record downwards" seems a lot harder! What a world where that's considered easier than other sensing options. I think vision is a good plan for a lake, with wide baseline. It's not great for a street with oncoming traffic. Turns out, however, that there are COTS radars that will work in the <100m range so I might go that route for the house, and try vision for the lake.

compressedgas 2y ago

See https://en.wikipedia.org/wiki/Lidar_traffic_enforcement https://en.wikipedia.org/wiki/Lidar_traffic_enforcement

solardev 2y ago
For tracking moving things from a stationary point, would you need some sort of "turret" that can track & aim the lidar? Or is there some equivalent of AESA in the lidar world? Edit: Apparently yes? Optical phased array lidars (https://lidarmag.com/2021/08/18/why-optical-phased-array-is-the-future-of-lidar-for-autonomous-vehicles/ https://lidarmag.com/2021/08/18/why-optical-phased-array-is-... or https://www.youtube.com/watch?v=5gml2tDogDI https://www.youtube.com/watch?v=5gml2tDogDI)

solardev 2y ago

You don't need to make your own radar and go through the FCC licensing on your own, though. There are commercially made hobbyist modules like https://www.digikey.com/en/products/detail/st-engineering-urban-solutions/HB100/24762149 https://www.digikey.com/en/products/detail/st-engineering-ur... that are already licensed: https://fcc.report/FCC-ID/VECHB100 https://fcc.report/FCC-ID/VECHB100

jvanderbot 2y ago
It's difficult to tell from the three page datasheet what effective range I would get. But that's a starting point at least.
- solardev 2y ago
  As other posters mentioned, you would probably quickly run into FCC issues trying to scale up the radar to something powerful enough to reach across a lake. Probably one of the other solutions (LIDAR, machine vision in the visible, etc.) would be better for that? Or if it doesn't have to be all the time, maybe just hover a drone above them and record downwards?
  - jvanderbot 2y ago
    "Just hover a drone over them and record downwards" seems a lot harder! What a world where that's considered easier than other sensing options. I think vision is a good plan for a lake, with wide baseline. It's not great for a street with oncoming traffic. Turns out, however, that there are COTS radars that will work in the <100m range so I might go that route for the house, and try vision for the lake.