HN user

jayyhu

555 karma
Posts11
Comments38
View on HN

AFAIK the Section 301 tariff (and increases) only applies to parts imported from China/HK. There are lots of manufacturers on DigiKey that make their parts from elsewhere where these tariffs are not assessed. As a data point, I recently bought a bunch of Lite-on LEDs on DK, their COO was Thailand, and I wasn't tariffed for those parts.

Consider a scenario where you're editing a function:

  function foo() { return a*2.1^2+0.52/2 }
So you do a find-all regex "1.*5" and delete all matching occurrences (à la CRISPER) to get:
  function foo() { return a*2.2/2 }
But unbeknownst to you, the code is littered with a bunch of commented out versions of the same function you're trying to edit:
  /* function foo() { return a*1.5/2.1 } */
  /* function foo() { return a*1.95/2.4 } */
And now those commented out versions now become:
  /* function foo() { return a*/2.1 } */
  /* function foo() { return a*/2.4 } */
And now the whole program doesn't compile anymore--or your patients get Leukemia. Oops.

While it might be hard for the US to make lithium batteries that are competitive economically, there are still many countries in the world that can make them economically that are not China, eg. SK, Japan, Taiwan, and the rest of SEA. For Skydio, surviving these sanctions is just a matter of moving their supply chain away from China.

From the article's opening sentence, it's clear that they are being sanctioned for doing business with Taiwan's Fire Agency, and not for any military reasons.

  A few weeks ago, China announced sanctions on Skydio for selling drones to Taiwan, where our only customer today is the National Fire Agency.

Sanction aside, this action is a wake-up call for all US based companies operating in geopolitically sensitive industries that they absolutely need to diversify their supply chain away from China.

And in terms of the sanction itself, it’s definitely a reasonable response by China, given the fact that DJI is heavily sanctioned by the US government.

I want to clarify that they actually did build a transistor-like device, and not just hypothesize about it. I missed section 3.2 when I initially skimmed the paper, which demonstrates and shows the results of a working “transistor”.

Unfortunately I can’t edit my original post, so apologies for causing any confusion.

Reading the article, it looks like so far they only have a working resettable fuse (a passive device), and only hypothesize that a transistor was possible with the copper-infused PLA filament. So no actual working active electronics.

And from the paper linked in the article[1], it seems the actual breakthrough is the discovery that copper-infused PLA filament exhibits a PTC-effect, which is noteworthy, but definitely not "3D-Printed Active Electronics" newsworthy.

[1] https://www.tandfonline.com/doi/full/10.1080/17452759.2024.2...

You're right, after re-reading the Power section on the datasheet it seems connecting 5V to the VREG_VIN should suffice to power the digital domains, but if you want to use the ADC, you still need a external 3.3V source.

I like the RP2040 2 years ago

The STM32 F0/G0/C0 lines come to mind. More I/O, more peripherals and built-in flash.

For hobbyist levels, buying 1-10 pcs they are comparable in price to an RP2040 + SPI flash. However at volume pricing, the STM32 MCU's can be cheaper than just the RP2040 itself. I do think Raspberry Pi needs to figure out volume pricing if they want to be competitive for anything that's not just hobbyists.

SPI Flash 2 years ago

Also you could potentially damage the on-board voltage converter/regulator, since most aren’t designed to be back-driven from their outputs.

To add to "capital-intensive": the regulatory framework right now (in the US) for drone delivery is uncertain at best. While most of the rules & regs to enable drone delivery is already finalized & published, a few very important ones (such as BVLOS - beyond visual line-of-sight) have yet been finalized, and thus need one-off waivers from the FAA to allow. And getting those one-off waivers is what eats a lot of time & money.

Airfoil 2 years ago

NACA and the other published airfoils[1] are generally a good starting point for hobbyist/RC folks. However if you want to eke out that last 5% bit of performance (ie. you are a company/institution), you would start with one of the above airfoils and optimize them to fit your flight envelope & mission profile. Here's a neat video of optimizing a round profile into an airfoil optimized for supersonic speeds [2].

[1] http://airfoiltools.com [2] https://www.youtube.com/watch?v=FHYTBguMfWc