otaviogood
Joined 16 years ago
Karma
319
Submissions
40
Member since
Dec 17
Recent submissions
Comment · 4 months ago
FWIW, I tried the prototype. It's very real. I scanned my hand and arm. It showed realtime images of slices of my hand as I dipped my hand in the water. Really amazing IMO. I think this will be a game changer when it comes out. It's just so easy to scan yourself.
Comment · 6 months ago
for an introduction to the CAD software, Kicad, which this project uses, I really liked "Shine on you crazy Kicad":
https://www.youtube.com/watch?v=eMW9ohCbcik&t=27s
It takes you from basics to buying a PCB from the manufacturer.
Comment · 8 months ago
Like many have said, start with Arduino-like boards + servos. You can get servo driver boards that let you plug in multiple servos to your Arduino without power problems. Get those from Adafruit. Then you can graduate to the "bus" style servos like Feetech if you want to load up on servos.
If you want to learn to make PCBs, this tutorial shows you how to design them in open source software and then get them made cheaply (highly recommend): https://www.youtube.com/watch?v=PlDOnSHkX2c
Get a CAD program like Onshape (I love Onshape). Learn how to use it to design 3d printed components. Get a 3d printer. Maybe Bambu Lab. Now you should be able to make nice form factors for your robots. If you want to graduate from 3d printing to Aluminum, then you can send your designs to a place like PCBWay or JLCPCB and get the aluminum parts reasonably cheap.
At some point when you want to make a more "real" robot, read this guy's thesis and try to understand almost all of it: A low cost modular actuator for dynamic robots https://dspace.mit.edu/handle/1721.1/118671 It goes over so many things that are useful, like types of actuators, how they're designed, controlled, etc. I wish I had read that earlier. Then if you want to make something like that, I highly highly recommend MJBots. https://mjbots.com/
Make something amazing!!!
Comment · 1 year ago
You might be reading into it too much. I think the originals were just random pieces of different kinds of paper. Graph paper, yellow lined, paper, blank white paper... I don't remember exactly, but I think the copies could be special paper with a colored backside so they would know which way was up really easily for the scanning process.
Comment · 1 year ago
DARPA scanned the shreds. The funny thing is, they didn't want to shred the original paper, so first they photocopied the paper in a high quality color copier, shredded it, and scanned it. And that's where the little yellow dots came from. :D
Comment · 1 year ago
Me and my team used these yellow tracking dots to reconstruct shredded documents for a DARPA shredder challenge over a decade ago. You can see our program highlight the dots as we reconstruct the shredded docs. https://www.youtube.com/watch?v=uzZDhyrjdVo
Thanks to that, we were able to win by a large margin. :)
Comment · 2 years ago
This is much more interesting if you see the animations. https://x.com/jaschasd/status/1756930242965606582
Comment · 3 years ago
‘1984 is 1 token. 1884 is 2 tokens.’
I would be surprised if they use this tokenization still as it’s not math friendly.
Comment · 3 years ago
Where do you see the room for improvement that gets you to much faster speeds? Also I love the single file to do everything. :)
Comment · 4 years ago
The geometry in my raytracer can either be ray-traced primitives, like spheres or boxes, or it can be "signed distance functions" (SDFs), which let you define all kinda of crazy shapes. Inigo Quilez does a good job of explaining SDFs here: https://www.iquilezles.org/www/articles/distfunctions/distfu...
The refraction math in my code is around line 799 or 809 depending on what you're looking for. There are a few errors in the refraction code in this version. :/ But caustics are handled well by my renderer.
Comment · 4 years ago
This article talks about a pretty full-featured ray tracer. If you just want to play around with some ideas and have fun, you can make different tradeoffs and still get very nice and fast renderings. Here's a ray tracer that I made that's GPU-accelerated and can make some nice looking images quickly in 1000 lines of code. https://www.shadertoy.com/view/4ddcRn The tradeoff is that it's all procedural graphics. So there are no triangle meshes and it would also be a bit tricky to implement a bidirectional ray tracer like this.
Comment · 5 years ago
I thought it would be nice to listen to these with my podcast player on iphone. Here's my too-complicated process that worked:
- in Chrome inspector, look at the network tab when you click play on a Feynman lecture. Right click the mp4 and do "copy as cURL".
- Go to command line (unix style) and paste. Then append to that command line something like "--output flp1.mp4". That will download the file locally with that file name.
- Put the file on Dropbox or something that will get it to your phone.
- From dropbox on iphone, share and export the file, then choose your podcast app. The podcast app that worked for me is "Pocket Casts".
- Now in Pocket Casts -> Profile -> Files, you should be able to play the mp4s with nice podcast-style controls and learn physics and be happy!
Comment · 5 years ago
Maybe we should have tried Daily. :) We tried Twilio video and unfortunately had a really hard time tracking down bugs. Wasted tons of time on that and then went back to doing our own stuff. :( I still don't know where the bug was. Could have been our code or Twilio's. But when we got rid of Twilio and used our own stuff, it resolved the bugs. Was a very frustrating process.
Also, the way Twilio video charges seems to assume lots of n-squared, high res connections, which we don't have, so for an application like ours, the cost can be more than 10x less.
Comment · 5 years ago
25 person Zoom calls aren't fun. So me and my friends made a virtual gathering space for people to host online events, meetups, social hours, etc.
Tech: Frontend uses Svelte / Snowpack, which is great. The game view uses the DOM, which is questionable, but my webgl implementation wasn't so hot either.
Backend is Firebase for general stuff, server written in Golang for the realtime game stuff, and another Golang server for video.
Main techincal lesson learned so far: WebRTC sure is a pain to get right across everyone's devices, browsers, and connections.
[ my public key: https://keybase.io/otaviogood; my proof: https://keybase.io/otaviogood/sigs/ncKWzs5ncmZhcTROrRQBN8sD6FD_aR5jBqX0tP_7CFs ]