It's great that opportunities like this exist. Doing a project like this at all is such valuable experience. You must have learned a ton and can take that with you for all future projects. The only real quibble is the experimental setup is not really scientifically valid. UV light on its own kills algae, so you're going to detect a monotonic effect roughly equivalent to the altitude increase assuming a reasonably constant rate of altitude increase just from the cumulative exposure. That's not the same thing as detecting a change purely because of altitude.
Who cares, though? Scientists train for many years to learn the details of experimental methods in their specific domain. The engineering and hacking experience on its own is what really matters here.
Congrats on the interesting project! I was curious to know more about the scientific payload: how did you measure the fluorescence? Did you apply excitation light continuously? Or did you rely on ambient light and correct for it when measuring fluorescence? Did you have a control on earth to compensate for any biological related effects? UV and even blue light can stress or even kill cells, or bleach the fluorescence proteins. How do you expect altitude to influence fluorescence? It would be great to look at some data (could not find it on the blog, or github). Acrylic blocks a substancial portion of the UV light!
Edit: Definetely agree with other comment that the whole experience is more important than these details.
Thank you for the kind words!
The fluorescence was originally meant to be measured with an AS7273 spectrometer (unfortunately bought a different one, still worked fine though), and measuring ~680 nm. Certainly not a great setup but it worked fine. Light was ambient through acrylic, and I found out far too late that UV blocking effects. Despite that, I feel like the data is still somewhat valid, maybe. I did do some testing with it back on earth, though I can't remember how it correlated.
> UV light, a form of energy, is defined as light having wavelengths between 100 nanometers (nm, 1 billionth of a meter in length) and 400 nm. [...]
> Most acrylic plastics will allow light of wavelength greater than 375 nm to pass through the material, but they will not allow UV-C wavelengths (100–290 nm) to pass through.
In terms of photonic permittivity,
Glass is better for cold frames and the like, because acrylic filters out UV light.
This is absurdly impressive. If you have any interest in doing some more flight software work in aerospace / space / missile systems, shoot me an email scott@orcrist.com
Image data and telemetry were sent in different messages, so it wasn't too much of a bottleneck. The images were about ~100 bytes while the telemetry was roughly 40.
It's great that opportunities like this exist. Doing a project like this at all is such valuable experience. You must have learned a ton and can take that with you for all future projects. The only real quibble is the experimental setup is not really scientifically valid. UV light on its own kills algae, so you're going to detect a monotonic effect roughly equivalent to the altitude increase assuming a reasonably constant rate of altitude increase just from the cumulative exposure. That's not the same thing as detecting a change purely because of altitude.
Who cares, though? Scientists train for many years to learn the details of experimental methods in their specific domain. The engineering and hacking experience on its own is what really matters here.
Congrats on the interesting project! I was curious to know more about the scientific payload: how did you measure the fluorescence? Did you apply excitation light continuously? Or did you rely on ambient light and correct for it when measuring fluorescence? Did you have a control on earth to compensate for any biological related effects? UV and even blue light can stress or even kill cells, or bleach the fluorescence proteins. How do you expect altitude to influence fluorescence? It would be great to look at some data (could not find it on the blog, or github). Acrylic blocks a substancial portion of the UV light!
Edit: Definetely agree with other comment that the whole experience is more important than these details.
Thank you for the kind words! The fluorescence was originally meant to be measured with an AS7273 spectrometer (unfortunately bought a different one, still worked fine though), and measuring ~680 nm. Certainly not a great setup but it worked fine. Light was ambient through acrylic, and I found out far too late that UV blocking effects. Despite that, I feel like the data is still somewhat valid, maybe. I did do some testing with it back on earth, though I can't remember how it correlated.
The data I have is here: https://github.com/radeeyate/StratoSpore/blob/main/software/... - just be warned that the altitude data still isn't the exact same as it was while in the air (GPS not working so I had to take it from someone else).
From https://hps.org/publicinformation/ate/q12178/ :
> UV light, a form of energy, is defined as light having wavelengths between 100 nanometers (nm, 1 billionth of a meter in length) and 400 nm. [...]
> Most acrylic plastics will allow light of wavelength greater than 375 nm to pass through the material, but they will not allow UV-C wavelengths (100–290 nm) to pass through.
In terms of photonic permittivity, Glass is better for cold frames and the like, because acrylic filters out UV light.
Also, Hydrogen peroxide (H2O2) is an algaecide.
/? hydrogen peroxide algaecide https://www.google.com/search?q=hydrogen+peroxide+algaecide
This is absurdly impressive. If you have any interest in doing some more flight software work in aerospace / space / missile systems, shoot me an email scott@orcrist.com
This is very interesting, would love to hear more about the algae based measurements.
Meanwhile in my attempt with High altitude balloon, I tried sending a whole image over Lora successfully of course in chunks.
https://codetiger.github.io/blog/sending-large-data-like-ima...
As an alternative to Lora, check out https://github.com/projecthorus/wenet
Keep doing amazing stuff and telling us about it. Very cool!
the 1080p ->> 18x10 pixel compression just to yeet images over LoRA is honestly more impressive than the algae part
It's amusing but I'm not sure I understand the point. Wouldn't it be better to use that bandwidth for more sensor data?
Image data and telemetry were sent in different messages, so it wasn't too much of a bottleneck. The images were about ~100 bytes while the telemetry was roughly 40.
++++Cool points for that name alone!
This is so interesting. I have nothing to add, other than congratulations, and good luck on your next project.