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.
radeeyate 14 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.
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 1 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 2 hours ago [-]
Impressive level of detail, impressive work for anyone, much less high school students.
verelo 2 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 1 hours ago [-]
the article says 28.42 km. where are you seeing 28000 km ?
verelo 1 hours ago [-]
yeah i have no idea why my brain decided to type that (twice...), its clearly 28km
ErroneousBosh 2 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 36 minutes ago [-]
Oh, yeah FM transmitters can require a fair bit of power.
What is it using then, LoRA type stuff?
radeeyate 17 minutes ago [-]
Yep, the radio link runs LoRa on the 33 cm band (915 MHz)
Rendered at 20:10:36 GMT+0000 (Coordinated Universal Time) with Vercel.
Buying a styrofoam box and just accepting that it's gotta be that shape and size feels like a huge waste.
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.
This is all very cool but this temperature reading caught my eye as unexpected.
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.
What is it using then, LoRA type stuff?