jfrd

Brandon helped me solve an interesting problem during my PhD. I was building a sun-tracking sensor for a solar-powered lunar rover, and I needed to calculate the vector from the robot to the sun.

Brandon showed me how to use skyfield to solve the problem for a robot on Earth, and then he went back and forth via email to show me how to solve the problem on the moon.

In the end, we used skyfield to generate lookup tables for the places and times that we cared about, and it worked out great!

Surprisingly you can solve massive TSPs using heuristics. The solutions are not guaranteed to be optimal, but they can get very close to optimal without a crazy amount of computing power.

The Concorde TSP solver can apparently solve instances with 85.6k cities to optimality. Pretty amazing!

Five to ten years ago this would have shaken up the robotics research community --- we used NUCs for all of our robots. Now that everything is a neural net, we use NVidia jetson boards for nearly everything.

Are any subtopics particularly interesting to you?

Mechatronics, Computer Vision, Control Theory, State Estimation, Path Planning, etc?

Check out PBRT, an academy award winning book about a rendering codebase!

https://pbrt.org/

I think it is a reference to “Cracking the Coding Interview”, a book that teaches you how to pass FAANG interviews.

Find a project you want to build and stop at nothing until it works. Repeat. Caveat: pick things that are just beyond your current level of knowledge.

I’m a PhD student with ~5years ROS experience. What is your programming experience level? Why do you want to learn ROS?

The Kershaw Leek pocket knife. Flips open one-handed and makes a satisfying “snick”. I’ve used mine daily for 5 years.

https://www.amazon.com/dp/B0009VC9YK/ref=cm_sw_r_cp_api_glt_...

Personally, I hate anything that clutters my home directory. Have they added an option to relocate ~/snap?

Could it be that the examples of “good” architecture were selected over centuries by the communities that chose to preserve them, while the “bad” examples were chosen by pretentious hacks who don’t have to live and work near these buildings?

I love the author’s point, but I wonder if there are better examples of modern architecture that just aren’t being celebrated by the in-crowd.

Reminds me of Howard Roark.

For those who didn't click the link, this is a joke response to the author's tweet:

"I am bracing for the inevitable comments about C++ being the most terrible thing since forever :("

Too bad C++ is the most terrible thing since forever.

https://twitter.com/Cor3ntin/status/1383875999033565194?s=20

Cool! Check out the textbook “Probabilistic Robotics” for great explanations of the Kalman filter zoo. Bayes Filtering, Kalman Filtering, EKF, UKF, Particle Filter, etc.

Could you add some instructions to the demo? Maybe it’s obvious and I missed it, but I can’t figure out how to rotate a piece. I’m using an iPhone.

Andy Warhol was surely some kind of marketing genius.

You could use a co-routine to generate the magic numbers. Something like this:

  def gen_magic_nums():
     for i in range(100):
        yield i**2

  for num in gen_magic_nums():
     add_to_plot(num)

I love my X1 Gen 7, but the black soft-touch coating started peeling within a week of buying it. I hope they've fixed that because it is otherwise my favorite laptop I've ever owned.

I emailed Ralph Baer when I was about 13 to ask if he knew where I could get an original pong chip to build my own video game. He sent me an extremely nice response explaining that he didn’t have any of the chip any more, but that I didn’t need it to build my own version of pong.

I really wish I could find that email.

I was never going to see a penny from social security anyway. Maybe this will save me two years of payments into the federal slush fund!

Nope. The Lidar pulses are encoded uniquely to each sensor, so one sensor can filter out an (already unlikely) direct hit from another lidar. The cameras are IR filtered and also unlikely to get hit by the lidar. Radar is pulse encoded in a similar way to lidar, although possibly more likely to lose performance if surrounded by a lot of other radar units. In general, dirt on your sensor lenses is a lot more annoying than interference from other cars.

I believe some of them are from inigo quilez. I know the snail is.

https://www.iquilezles.org/store/

I read Cuckoo’s Egg and also liked “The Soul of a New Machine”, “SkunkWorks”, and “The Making of the Atomic Bomb”.

Iterative Deepening A Star