Axon in Space (seriously, I sent it to space)

[Admin]

How is admin going to keep his street cred if he doesn't do things like send an Axon to space?

background:
I joined up with a talented crew at HacDC to launch a physics experiments and cameras up into space.

The package had 3 cameras, 3 microcontrollers, an accelerometer, a Geiger counter, 3 temperature sensors, a pressure/altitude sensor, 2 GPS units, and 2 transmitters. About 2/3rds of it worked . Despite losing GPS for 3/4ths of the flight, we had a record recovery of just minutes after touchdown!

It went up higher than 75000 ft (23 km). My job was to measure temperature, air pressure, altitude, GPS time, and radiation. The radiation measurement failed because we dumbly used a dead battery by accident. Oops . . .

Oh, and I have more detailed videos of how I did the hardware, but I'll put those up later when I have more time.

image gallery:
http://gallery.jbwa.net/SpaceBlimp/SB3/

SpaceBlimp 3

[dunk]

good job!
congratulations on the successful retrieval.

did i hear correctly on the video that the GPS failure was due in part to the GPS being in ground vs aviation mode?
that would explain why GPS started working as the payload descended.

what was the flight time? any problem with cold killing batteries?


dunk.

[Admin]

The flight time was exactly 2 hours, and the time between turning everything on and turning everything off was 3.5 hours.

We used non-rechargeable 9V lithium batteries and homemade packs of AA lithium cells. They said lithium performs really well in cold. And they were well insulated anyway, reaching only ~-3C inside the capsule where my Axon was.

did i hear correctly on the video that the GPS failure was due in part to the GPS being in ground vs aviation mode?

There were two GPS, one stopped getting a lock as soon as we packed it up. We never figured that one out, but it got a lock again as soon as we took it out. Probably all those batteries blocking the signal I guess.

The other one, yeap, we accidentally forgot to put it in aviation mode. So we lost coordinates as soon as it went above 40k feet.

The moral is, even with a backup system for everything things can still go wrong!

[Admin]

We sent another up into space, this time 103k feet. And this time the camera didn't fail . . . well, at least until atmospheric re-entry . . .

Have I restored my street-cred, yet?

Amateurs send robot into space!

[hopslink]

Nice one Admin! 

More details please.

[Admin]

http://wiki.hacdc.org/index.php/HacDC_Spaceblimp_4

[Ryltar]

That is awesome. I'd say your street-cred is restored.

[dunk]

interesting data graphs.

i'm surprised to see how linear the rise speed was.
i guess drag must be roughly proportional to the expanding balloon size as the altitude increases.
was this because of careful calculation of the balloon size or is that just how these graphs tend to look?

i also would not have expected to see such a large temperature rise high up.
i'm guessing this is due to the reduced thermal conductivity of the atmosphere but increased heat radiation (ie. sunlight).
it would be interesting to see if you can rig a temperature sensor in the "shade" on the next one to see if this is a true representation of the air temperature or just the effect of sunlight on the probe.

were you able to correlate the lowest temperature point with any particular weather phenomena on the film?
was that where it broke free of cloud?

the lowest temperature was slightly warmer on the descent. do you think this was due to air friction or residual heat in the sensor?


2 interesting sensors for next time:
air pressure and humidity. both these variables have a large effect on the conductivity of air so would compliment the temperature data.


anyway, good job.
i'd love to build a controllable airframe that could return to base for this sort of project....

dunk.

[BANE]

admin,
I read that you used an on board data logger.  What type did you use and did you use it with the axon II?  Where can i buy one?  Can i dump the data in excel or does it have a program it works with?

Ive been wanting to do thing similar (data logging) with a robot (output from axon II) but for motor controller temperature, motor temperature, motor voltage, battery voltage... ect and have some program graph everything out.

[Admin]

i'm surprised to see how linear the rise speed was.
i guess drag must be roughly proportional to the expanding balloon size as the altitude increases.
was this because of careful calculation of the balloon size or is that just how these graphs tend to look?

No idea why, but definitely not careful calculation lol

i also would not have expected to see such a large temperature rise high up.
i'm guessing this is due to the reduced thermal conductivity of the atmosphere but increased heat radiation (ie. sunlight).

Yeap, no air to cool down the heating electronics, and sunlight is ultrahot up there.

it would be interesting to see if you can rig a temperature sensor in the "shade" on the next one to see if this is a true representation of the air temperature or just the effect of sunlight on the probe.

hmmmm good point . . .

were you able to correlate the lowest temperature point with any particular weather phenomena on the film?
was that where it broke free of cloud? the lowest temperature was slightly warmer on the descent. do you think this was due to air friction or residual heat in the sensor?

The coldest internal temperature is always during atmospheric re-entry. When it goes up, all the air goes out of it. When it comes back down, it sucks the cold air from the jet-stream to fill it back up.

2 interesting sensors for next time:
air pressure and humidity. both these variables have a large effect on the conductivity of air so would compliment the temperature data.

I did air pressure last time, it wasn't that exciting. I bought a humidity sensor for this but I didn't realize until too late that it required 5V (I was using a 3.3V mcu).

i'd love to build a controllable airframe that could return to base for this sort of project....

Unfortunately thats illegal in the US, otherwise I would have done it by now

(AUVs cannot go above 400ft and must always be in physical site, by law)

I read that you used an on board data logger.  What type did you use and did you use it with the axon II?  Where can i buy one?  Can i dump the data in excel or does it have a program it works with?

I used the EEPROM built into the Axon for memory storage. I have code I can give you when you're ready. It easily dumps into excel.

[BANE]

I have code I can give you when you're ready. It easily dumps into excel.

So true; i going to try to read and write integers to the axon's internal eeprom here in a second just to get the hang of it first. 

[Admin]

My example code (written with help from Webbot) is attached.

Just call this function in your main to run it:
writeLog();

And call this line to output EEPROM back to hyperterminal:
print_out_EEPROM();


In the attached file, you see this line and stuff below it:
// Populate the entry with the date, time and sensor values

Thats where it copies the global variables from RAM into the local values for EEPROM.

Make sure you change MAX_RECORDS to match the EEPROM size of your mcu.

[BANE]

thanks admin, this should work perfect for what i want to do eventually.

However, im currently having some compiling warnings just trying to write/read a single int.  I'll make a new thread so i dont hijack this one

[raptorwes]

That's pretty cool . Do you have to file a flight plan or anything with the state or federal gvt to launch something like that ?

[Admin]

That's pretty cool . Do you have to file a flight plan or anything with the state or federal gvt to launch something like that ?

Depends on what you're flying, and if your flight plan enters restricted airspace or not . . . you'd have to check the regulations.

We did, but we didn't have to for what we were doing.