HABE 2

Data, Data And More Data

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Following last Saturday’s successful flight of HABE 2 and the new addition of a “black box” style SD flight logger I have collected a wealth of data. Having spent some of yesterday writing a C command line program to parse through the log file, earlier today I managed to extract the information and pop it into an excel spreadsheet.

Having plotted some fancy graphs etc the results where fantastic. All of the graphs offer a unique story and contain lots of useful information – a great success. I’ve decided to distribute the excel spreadsheet containing all the raw data and graphs etc so people can have a look at all the information. It may prove useful to some. The excel workbook can be downloaded here (xlsx) and an older (xls) version here.

I’ve posted the graphs below for all to see:

A few brief notes on the graphs:

  • The temperature graphs have the ascent on the right (slightly warmer) and descent on the left (slightly cooler).
  • It can clearly been seen that the coldest temperatures faced reside in the 10-12km altitude bracket. As the balloon rises above this altitude it actually gets warmer contrary to popular belief! The science behind this: the upper layers (stratosphere) absorb UV radiation far more efficiently than the lower layers, therefore this acts as a heating effect – it also prevents extreme UV readings on the surface of Earth.
  • The solar panel readings are extremely interesting and probably contain the most information. On initial observation I didn’t see that much information, but on closer observation there is a lot said. Firstly – why the mass scatter of points everywhere?! Well, I believe this is due to the swinging of the payload (due to winds); as the solar panels were mounted on top of the payload and the sun was relatively low in the sky (Winter), this would have caused differing levels of light falling on the solar panels, indeed at some point they were probably in shade hence the many near 0v readings. Secondly you may ask, ok, why isn’t that the case for the lower altitudes (<10km)? The answer to this – the payload was in the clouds through this part of the flight. Clouds act to diffuse the light from the Sun and therefore are bright all around inside them – so whether the payload was on it’s side or pointing upright the light falling on the solar panels was much the same. On close inspection (you made need to download the full quality versions – excel workbook) the readings seem to fall into rectangles at lower altitudes – I believe this is the case because of the different cloud layers. From the photos taken by the onboard camera it’s clear that there were multiple cloud layers and each layer would’ve had unique properties – hence differing voltage/power constraints. Interesting!

I have annotated the first altitude vs SP1 voltage graph illustrating the different “rectangles” – take a look:

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I’ve also done the customary 3D Google Earth plot of the flight path. You can download the KML file here and have a play about with it in Google Earth.

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Last but not least, here are some interesting facts about the flight:

Max Internal Temperature: 19.6
Max External Temperature: 16.3
Min Internal Temperature: -26.8
Min External Temperature: -63.1
Max Altitude Recorded: 29958
Max Voltage (SP1): 7.67
Max Voltage (SP2): 8.96
Average Voltage (SP1): 1.88
Average Voltage (SP2): 2.51
Max Power/mW (SP1): 406.28
Max Power/mW (SP2): 419.23
Average Power/mW (SP1): 44.58
Average Power/mw (SP2): 58.92

HABE2 Launch Tomorrow!

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Well – what a frantic few days it has been… I’ll give a brief run through as the payload still need completing!

Wednesday afternoon: I was on the IRC and David Akerman (daveake) posted a link for the prediction for his launch this Saturday. It looked like a good prediction, so I decided to run one from my launch site; no intention at this stage to launch. It turned out to be a great prediction, actually landing in this country (the previous weeks had been landing in France or beyond!). There were two big issues at this point: 1) The payload wasn’t even completed and there were still some nasty bugs present in the code. 2) I didn’t have permission to launch.

After a quick call to the CAA I managed to obtain permission for this weekend (4th/5th Feb) – many thanks to David Miller at the CAA for getting this sorted in such short notice. As of yesterday evening, I now have permission to launch. The next big hurdle was getting the payload completed on time. Despite the huge number of hours I had put in the past 2 weeks, it still wasn’t stable – albeit a rather buggy beta version.

Over the last day and a bit I’ve fixed all the bugs I can see and built most of the payload stuff. Yesterday I ran a full systems check and everything worked apart from the camera – oh no, not this again… (you’ll probably remember that HABE1 was plagued by complete camera failure). This however, wasn’t linked to the HABE1 bug. Initially I thought it was a software issue as I’m running a modified version of CHDK that allows me to switch between photos and video (risky, I know..). However, it appears to be it was actually a failure of the alkaline batteries due to the cold temps outside. This meant I only got around 100 photos (only the 1st 30mins of flight) before the batteries conked out. For the flight I will be using lithiums which have a much better tolerance to cold temperatures thankfully… As I’m writing this the camera is outside with lithiums in running a final check. If it’s all positive then it gets the clearance to fly from me!

Lastly, I’ve just finished soldering all the solar panel logging equip up; I just need to pop the flight board in and solder up all the antennas (not an easy job at all). After – final checks, then time to pack the car for tomorrow.

The current prediction is ok – not great – but ok. I’ll be monitoring this throughout the day and tomorrow morning.

What’s new/updated on HABE2:

  • Software rewrite – this has resulted in a fair few bugs as I didn’t test as I was going along (mistake), though it’s resulted in a more efficient and readable software
  • Swapped old temperature sensors out for newer high precision ones
  • Uplink is present – simply to test range (let me add at this point I’m not expecting great range)
  • Camera now takes video as well as photos
  • “Black box” present on the flight – SD card logging system should log everything for review after the flight
  • Cutdown module – this can be activated via uplink and is automated by the flight computer should the payload stray outside a “safe” area
  • Solar panels – 2 high performance small solar panels present; I’ll be logging data using two different loads.

Launch details:

  • Launch site: Ombersley, Worcester.
  • Estimated time of launch: 11am GMT (setting up around 10am)
  • Flight time: approx 2.5hrs
  • Check here, twitter (@adamcudworth) or the IRC for the most up to date information regarding the launch. If you would like to come along to the launch please drop me a line either by email or the IRC (#highaltitude and my nickname: cuddykid).
  • Track the balloon live during the flight here
  • I would really appreciated any help – whether it’s turning up to help out with setup/launch, or helping track by listening in – thanks!

Hopefully the launch will be underway within 24hours! Over and out…

For the most up to date info during the launch, check the live tracker, my twitter or the IRC (#highaltitude). 

CAA Permission Requested

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Just a brief update regarding HABE 2:

I have just sent off for permission to launch the balloon from the CAA. I have specified the last weekend in February and the first 2 weekends in March. I have two main doubts currently:

1) Will I complete the payload on time. There is still a LOT to do and none of the code that I have written has been fully tested yet. If a fairly major bug is present in the code then it will require a significant amount of time debugging.

2) Wind conditions – It’s a very windy time of the year and the high altitude winds tend to blow in the wrong direction (west to east) at this time of the year. Hopefully they’ll be fine for given dates *fingers crossed*.

A note on the side; if you haven’t already noticed there is now a brand new page called “Checklist” where you can track my progress. “Check” it out ;)…. (it’s in the toolbar at the top if you can’t find it!).

HABE 2 – Update

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It’s been a long time since I last updated the blog so here’s a quick update as to what’s happening with HABE 2:

Software

The code for the next flight is being mostly rewritten aiming to make it more efficient and easier to read/adjust where necessary. A few weeks back I spent a significant amount of time on the code and as a result it is near completion. There are still however a few more additions and tweaks needed.

Hardware

Whilst the core tracking and telemetry system of HABE 2 will be the same as HABE 1, there are quite a few new additions that are going to be present on the next flight:

  • Attempt at an uplink – using some easyradios an uplink is going to be attempted. Note: I am not expecting great range, this is merely a test to see just how far an uplink can be maintained with a tiny 10mW transmitter
  • Solar panels – 2 high performance small panels will be flown purely to collect data to determine the plausibility of powering future flights using them
  • Tiny keychain video camera – an extremely cheap video camera will hopefully capture some video footage of the flight (although I’m not expecting anything great – at all!)
  • A570 video mode – using the CHDK software hack I have enabled easy switching between still and video mode. Plans on when video mode will be switched on are currently undecided
  • Cutdown module – whilst I have tested a couple of cutdown modules I’ve designed using nichrome wire I have yet to settle on a design and finalise plans here. A cutdown will be deployed for 2 reasons: 1) many flights with Hwoyee balloons (ones I’m using) have developed a mysterious floating capability resulting in the loss of payloads as the balloon floats off to another country, using a cutdown with a “geofence” will allow me to cut the payload and parachute away from the balloon if this occurs. 2) HABE Glider will require a cutdown module and therefore this flight will act to test out the chosen mechanism

Along with these additions the bugs from HABE 1 have been patched (hopefully!). Most of the systems are currently in prototyping stage (on a breadboard) and are yet to be soldered for the flight. There is the chance that some of the above won’t make it for the next flight and/or some other things may be added.

My aim is to launch HABE 2 before Summer. Current target is around Easter, perhaps before if I get a move on. Though, as always this depends on a range of uncontrollable factors: CAA permit, weather…

Over and out for now

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