Show HN: We chased a weather balloon across Montana and never found it (radi8.dev)
41 points by radeeyate 3 hours 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!
colingauvin 8 minutes ago
I live in Montana and routinely hunt the Musselshell river valley/Meagher county area. It's maybe my favorite place in the world. So few folks have been there, but spend some time there and you might just find yourself feeling depressed when you leave and not knowing why.
Glad to see other folks go through the area. The wind in Judith Gap is insane, so I'm surprised that you never found it. I'll keep an eye out when I'm out there in Sept/Oct.
happyopossum 2 hours 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
Buying a styrofoam box and just accepting that it's gotta be that shape and size feels like a huge waste.
radeeyate 40 minutes ago
I think another point I hadn't included was the flexibility I had with prototyping different boxes. The hardware was changing all the time, and being able to just 3d print another revision was very convenient.
If I did something like that with styrofoam, it probably would have gotten pretty expensive. The precision you get from printing was also a plus, as there needed to be slots for cameras, antennas, and circuit board mounting holes.
TylerE 13 minutes ago
What's expensive? You can buy a medium sized cooler for $5 at Walmart. That's a fair bit of foam.
rtkwe 2 hours ago
Seems like the simple solution is a Styrofoam sheet, a $10 hot knife and some glue solves the customization problem almost trivially.
nkrisc 2 hours 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.
macintux 3 hours ago
Impressive level of detail, impressive work for anyone, much less high school students.
verelo 3 hours 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 2 hours 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 2 hours 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.
newtwentysix 2 hours ago
ErroneousBosh 3 hours 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 2 hours 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.
ErroneousBosh an hour ago
Oh, yeah FM transmitters can require a fair bit of power.
What is it using then, LoRA type stuff?