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Ask HN: Most interesting tech you built for just yourself?

1901 points l2silver | 18 comments | 27 Apr 23 15:04 UTC | HN request time: 0.759s | source | bottom

Maybe you've created your own AR program for wearables that shows the definition of a word when you highlight it IRL, or you've built a personal calendar app for your family to display on a monitor in the kitchen. Whatever it is, I'd love to hear it.
1. dllu ◴[28 Apr 23 18:48 UTC] No.35745463[source]▶
Have you considered getting a line scan camera for sharper and higher resolution images? I took some train scans with one: https://daniel.lawrence.lu/photos/

Incidentally I also built some tech for it: https://github.com/dllu/nectar but I need to update the readme...

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2. seabass-labrax ◴[28 Apr 23 19:56 UTC] No.35746302[source]▶
I remember seeing your photographs on Wikimedia Commons and wondering how you did them - now I know! I always assumed that you just used a very quick shutter with an f-stop of zero :)
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3. mcast ◴[28 Apr 23 19:58 UTC] No.35746328[source]▶
Thanks for sharing, those photographs are very clear and sharp (especially this one: https://pics.dllu.net/file/dllu-pics/boston-pcc.jpg) it seems to tickle my brain.
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4. stavros ◴[28 Apr 23 20:30 UTC] No.35746709[source]▶
I know he told us how already, but that would have left the background sharp, rather than always the same.
5. cinntaile ◴[28 Apr 23 20:46 UTC] No.35746904[source]▶
This reminds me of Wes Anderson movies for some reason.
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6. bradgessler ◴[28 Apr 23 22:26 UTC] No.35747895{3}[source]▶
His style is to shoot his subjects straight-on. Most other movies have the camera at an angle.
7. jo-m ◴[28 Apr 23 23:09 UTC] No.35748299[source]▶
Wow, the pictures look amazing! Yes, the look of line scan images were an inspiration for this project. But of course, I also tried to keep BOM costs down and so ended up with a RP4 + RPi Camera.
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8. dllu ◴[28 Apr 23 23:12 UTC] No.35748327[source]▶
The RPi HQ camera is a nice step up from the regular RPi camera while being not too expensive too. Incidentally, I also have a project using that [0] but unfortunately no trains where I live.

[0] https://daniel.lawrence.lu/blog/y2022m01d27/

9. dllu ◴[28 Apr 23 23:21 UTC] No.35748386[source]▶
I have three of those actually:

https://daniel.lawrence.lu/photos/pcc

Technically, the photo could be twice the resolution, since the length of the line scan sensor is 4096. It consists of two lines, RGRGRG and GBGBGB. By interpolating the red and blue channels, it would be possible to get images 4096 pixels tall. The challenge is that the two green channels apparently have quite different sensitivity and also each pixel has some variation in sensitivity, which also seems to drift with temperature and settings, so it's quite annoying to calibrate everything properly haha.

10. dllu ◴[28 Apr 23 23:23 UTC] No.35748407{3}[source]▶
I'm a big fan of Wes Anderson's aesthetics and would love to shoot that funicular train from Grand Budapest Hotel (which actually exists --- the Buda Hill funicular) using my line scan camera.
11. dllu ◴[28 Apr 23 23:29 UTC] No.35748450[source]▶
I have a huge backlog of photos that I need to contribute to Wikimedia Commons! I'll get around to doing it eventually, hopefully before 2045.
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12. svara ◴[29 Apr 23 10:28 UTC] No.35751665[source]▶
How do you get the x scaling right? You have to measure the speed of the train somehow?
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13. maurits ◴[29 Apr 23 11:02 UTC] No.35751821[source]▶
Your blog is a gem, thanks for sharing!
14. qwertyuiop_ ◴[29 Apr 23 11:35 UTC] No.35751980[source]▶
Woah the resolution! You can see the earpods on a person behind the tinted windows of Shinkansen.
15. dahart ◴[29 Apr 23 13:55 UTC] No.35752870[source]▶
I love how the line scan camera’s horizontal background makes it look like the trains are moving impossibly fast. Not only are the images sharp & high res, it has a great aesthetic and implies you were tracking an action shot.
16. dllu ◴[29 Apr 23 19:33 UTC] No.35756292[source]▶
When the train is moving at a constant speed, you can just scale the image manually to make it just right. If it's moving at a non-constant speed, you can apply a spline or similar to remove the distortion.
17. IIAOPSW ◴[30 Apr 23 09:09 UTC] No.35760889[source]▶
Have you tried the opposite direction? Sitting on the train with the line feed and taking a picture of outside? Like say, a panorama view of the entire run-length of the line, distorted in proportion to the trains turns and accelerations.
18. seabass-labrax ◴[30 Apr 23 22:14 UTC] No.35767067{3}[source]▶
Do it sooner than 2038 and you get the privilege of 32-bit timestamps on the metadata :)