Show HN: We chased a weather balloon across Montana and never found it

25 points by radeeyate an hour ago

Since April, I have been working with Sam Flynn (https://drook.dev) to make this balloon payload, UpLink. We did a similar launch last year with Hack Club but this was our first independent launch.

UpLink was a 491 gram payload testing the insulation properties of 3D printing filaments, while also transmitting 320x240 images over a radio link -- up from the 18x10 images last year!

This is a writeup on our engineering process, mistakes made, and learning experiences. It covers:

- Custom electronics designed in KiCad

- Firmware design

- Results from the data we received on the ground

- Image transmission

- Launch day logistics, and where things went wrong

All hardware, software, firmware, and CAD is available on GitHub: https://github.com/radeeyate/UpLink, licensed + certified as open source hardware: https://certification.oshwa.org/us002826.html

If you just want to see the images received, I put up a gallery here: https://uplink.gallery.radi8.dev/

If you have any questions, comments, or concerns, let me know. I'm happy to answer anything!

happyopossum - 39 minutes ago

Fun writeup! I was surprised by the part about styrofoam boxes though:

  Despite their popularity, they have a few disadvantages:

  They come in predefined sizes which mandate a certain weight allowance
  They cannot be flexible for your specific payload, making it hard to be efficient with payload layout
  They are expensive compared to more custom solutions

This shocks me, as styrofoam is one of the easiest materials in the world to cut, shape, fasten, and customize to your heart's content. I'm all for 3d printing stuff, but in the theater world we build a ton of very detailed (and shockingly durable) stuff out of foam all the time....

Buying a styrofoam box and just accepting that it's gotta be that shape and size feels like a huge waste.

nkrisc - 15 minutes ago

In my intro Industrial Design class long ago we fashioned styrofoam and many other kinds of foam into every shape imaginable with a hot wire, some utility knives, and contact adhesive. A wood rasp worked well for organic and rounded forms (wear a mask), though that’s probably not needed in this application.
rtkwe - 32 minutes ago

Seems like the simple solution is a Styrofoam sheet, a $10 hot knife and some glue solves the customization problem almost trivially.

verelo - an hour ago

Wait, so at 28k/km the temp goes up to 15C?

This is all very cool but this temperature reading caught my eye as unexpected.

radeeyate - an hour ago

I found that surprising too! This probably isn't a completely accurate number, as the sensor is black and likely experienced some heating from the sun. Something also worth noting is that different layers of the atmosphere experience different temperatures www.noaa.gov/jetstream/atmosphere/layers-of-atmosphere
- verelo - an hour ago
  
  Amazing. I love that i didn't know this. When i was studying weather as part of my pilots license i noted the basic mental math that i'd lose ~2 degrees celsius per 1000ft, but never did i take a second to ask, what happens when i go up 28,000 km.

macintux - an hour ago

Impressive level of detail, impressive work for anyone, much less high school students.

ErroneousBosh - an hour ago

The images seem a bit scrambled, presumably due to missing data blocks. At that low a resolution, have you considered maybe Robot36 SSTV?

radeeyate - an hour ago

Images are all in order, but some have missing packets.
The problem with SSTV is the power required. From some looking it seems that transmitting would need at least 5 watts. This wouldn't be feasible running on the balloon, as it was powered by Energizer Ultimate Lithium batteries.