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dllu commented on Rivian Unveils Custom Silicon, R2 Lidar Roadmap, and Universal Hands Free   riviantrackr.com/news/riv... · Posted by u/doctoboggan
OneDeuxTriSeiGo · 2 days ago
NGL I thought sub 1550nm LIDAR had been banned for use in new automotive applications already? I clearly must be mistaken but I had thought that was the case.
dllu · a day ago
Not banned. In addition to the Chinese lidars I mentioned, the Valeo Scala on Audi cars is 905 nm, and then there are also Ouster (865 nm), Innoviz (905 nm), Livox (905 nm) etc. The large spinning lidar on top of the Waymo Jaguar I-Pace is also purportedly 905 nm, although in the past they also had a swivelling 1550 nm lidar in the dome of the Chrysler Pacifica cars (situated just underneath a smaller spinning 905 nm one).

The eye safety threshold for 850/905 nm is a lot lower than 1550 nm, so they output way less power, but the much better sensitivity of silicon sensors makes up for it partially. You can also squeeze out more range using clever signal processing and a large optical aperture (which allows you to output more light, but since the light is spread out across the aperture, the intensity doesn't exceed the threshold). Typically, the range of 850/905 nm lidars is less than that of 1550 nm lidars though.

On the bright side, due to lower power, there hasn't been any instances (to my knowledge) of 850 nm and 905 nm lidars damaging cameras, whereas at least two different 1550 nm lidars have been known to destroy cameras (Luminar and AEye).

On the Luminar lidar website [1] they proudly advertise "1,000,000x pulse energy of 905nm".

[1] https://www.luminartech.com/technology

dllu commented on Photographer built a medium-format rangefinder   petapixel.com/2025/12/06/... · Posted by u/shinryuu
dllu · a day ago
Really awesome design! It would be wise to replace some of those 3D printed parts with CNC parts, especially for places where a lot of strength is required (eyelets for those Peak Design anchors) or precision is required (lens mount). I myself have 3D printed some parts for my line scan camera too, so I can totally understand.

[1] https://daniel.lawrence.lu/blog/2024-08-31-customizing-my-li...

dllu commented on Rivian Unveils Custom Silicon, R2 Lidar Roadmap, and Universal Hands Free   riviantrackr.com/news/riv... · Posted by u/doctoboggan
OneDeuxTriSeiGo · 3 days ago
Depends on the type of LIDAR. LIDAR rated for vehicle use is at a wavelength opaque to the eyes so it hits the surface and fluid of your eye and reflects back rather than going through to your cones and rods.

It isn't however opaque for optical glass (since the LIDAR has to shine through optical glass in the first place) so it hits your camera lens, goes straight through, and slams the sensor.

dllu · 3 days ago
You seem to be implying that all automotive lidar are 1550 nm but that's not true. While there are lots of 1550 nm automotive lidars (Luminar on Volvo, Seyond on NIO) there are also plenty of 850 nm to 940 nm lidars are used in cars (Hesai, Robosense, etc). Those can pass through water and get focused to your retina, but they are also a lot lower power so they do not damage cameras.
dllu commented on Rivian Unveils Custom Silicon, R2 Lidar Roadmap, and Universal Hands Free   riviantrackr.com/news/riv... · Posted by u/doctoboggan
tennysont · 3 days ago
Why wouldn’t your eye lens focus LIDAR photons from the same source onto a small region of your retina in the same way that a phone camera lens focuses same-origin photos to a few pixels?

Sorry if this is a silly question, I honestly don’t have the greatest understanding of EM.

dllu · 3 days ago
Depends on the wavelength of lidar. Near IR lidars (850 nm to 940 nm, like Ouster, Waymo, Hesai) will be focused to your retina whereas 1550 nm lidars (like Luminar, Seyond) will not be focused and have trouble penetrating water, but they are a lot more powerful so they instead heat up your cornea. To quote my other comment [1]:

> If you have many lidars around, the beams from each 905 nm lidar will be focused to a different spot on your retina, and you are no worse off than if there was a single lidar. But if there are many 1550 nm lidars around, their beams will have a cumulative effect at heating up your cornea, potentially exceeding the safety threshold.

[1] https://news.ycombinator.com/item?id=46127479

dllu commented on Framework Laptop 13 gets ARM processor with 12 cores via upgrade kit   notebookcheck.net/Framewo... · Posted by u/woodrowbarlow
nottorp · 9 days ago
But has Asashi managed to have support for bells and whistles like graphics acceleration and sleep by now?

This SoC may actually have Linux drivers.

dllu · 9 days ago
It does have graphics acceleration and you can even play AAA titles with fex [1] since last year. But many bells and whistles still don't work --- for example, the video decoding hardware, proper sleep, etc.

Anyway, I've been using it on my Macbook Air M2 and it works fine for my use case [3]. Pretty smooth.

[1] https://rosenzweig.io/blog/aaa-gaming-on-m1.html

[3] https://daniel.lawrence.lu/blog/2024-12-01-asahi-linux-with-...

dllu commented on Multivox: Volumetric Display   github.com/AncientJames/m... · Posted by u/jk_tech
dllu · 10 days ago
I once considered making a spinning persistence of vision similar to this one specifically for visualizing lidar data from a spinning automotive lidar. The lidar has 128 beams and you could make a spinning array of 128 1D LED displays at exactly the same beam angles to recreate the point cloud from the lidar.

Anyway, I was too lazy to make it, but it's super neat to see that someone actually made something similar.

dllu commented on All about automotive lidar   mainstreetautonomy.com/bl... · Posted by u/dllu
jaimex2 · 11 days ago
Thanks to Tesla all this stuff will be in a museum shortly.

Lidar is flawed at the foundational level. There's a reason no living creature on earth evolved it.

dllu · 11 days ago
Velodyne actually donated an HDL-64E to the Smithsonian.

[1] https://lidarmag.com/2011/05/21/velodyne-donates-lidar-and-r...

dllu commented on All about automotive lidar   mainstreetautonomy.com/bl... · Posted by u/dllu
alexpotato · 11 days ago
Some other comments have posted about the laser safety being the issue but I have a more physical story:

Recently got a Waymo for the first time to take my kids and I from one hotel to another in Phoenix.

- Car pulls up

- I walk up to the trunk as I have a suitcase

- Out of habit, I go to open the trunk by pressing the button under the "handle" (didn't realize you have to unlock the car via the app first)

- My hand moves by the rear trunk laser that is spinning and "whacks" my hand.

Not a big deal but seems like an interesting design choice to place a motorized spinning device right next to where people are going to be reaching to open the trunk.

dllu · 11 days ago
The externally spinning Waymo Laser Bear Honeycombs do indeed cause whacking and pinching and occasionally get gunked up with wet leaves and debris. One reason why they are like that is because these have very large fields of view. A cylindrical plastic cover seriously degrades optical quality especially when the beam is hitting it at a steep angle. Another reason is that it has a heatsink on the back of the spinny part. Earlier Waymos like the Firefly in fact cover up this lidar, e.g. on the "nose" and the side mirrors [1]. But they went back to leaving it exposed for better performance.

Likewise with the big spinning lidar on top, which was covered in the older Chrysler Pacificas but externally spinning in the newer Jaguar I-Paces.

[1] https://commons.wikimedia.org/wiki/File:Waymo_self-driving_c...

dllu commented on All about automotive lidar   mainstreetautonomy.com/bl... · Posted by u/dllu
amelius · 11 days ago
For the downvoters:

https://en.wikipedia.org/wiki/Beamforming

It is possible for the array to produce a concentrated beam into one direction. The software determines when that happens and in what direction.

dllu · 11 days ago
Beamforming with a phased array is talked about in the article, but you are conflating two very different types of arrays. You can't form beams with the types of macroscopic arrays I was referring to, since they consist of macroscopic array elements whose phase cannot be controlled, and reside behind a fixed lens that ensures that they all point in different directions.
dllu commented on All about automotive lidar   mainstreetautonomy.com/bl... · Posted by u/dllu
xattt · 12 days ago
I am surprised that I didn’t see discussion about Audi’s lidar that’s been in use in production vehicles now. Yes, it’s on a different level, only used for ADAS, but it’s still lidar that’s actively used.
dllu · 12 days ago
If I remember correctly, the Valeo Scala that's in the Audi cars uses a discrete 16 element 1D array (940 nm diodes + APDs) plus a rotating mirror to scan.

u/dllu

KarmaCake day1570January 13, 2012
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