High altitude balloon payload, from Sable-3 discussion Options

[paxdan]

I have been following this thread pretty closely. I though the following links from makezine.com might be interesing:

Video podcast part 1 and part 2 about lanching a balloon with 4 canon sd cameras set up to take a panoramic picture every 7 seconds.

The second is a successful following the make guidelines using a video camera.

seeing the gondolas used is very interesting.

My 2cents, make sure you stick your name, email address and telephone number on the outside of the box and on the individual components inside.

[djellison]

Their wiki doesn't have many details on the timing circuit - that's exactly what I need. PICAXE might do the job - looks like the sort of controller that a moron like me can code, but will do what we need.

I have a LOT of that foam around - it's awesome.

[JRehling]

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[djellison]

It's probably wishing too much

We're talking about a digital camera bought for less than £10.

Doug

[DEChengst]

This sounds pretty exciting In my mind this can be something with a lot of potential. First starting out with simple designs just to learn how to build, launch, take data and finally make a safe landing. The next step would be to fly real scientific instruments. The final step would be to fly on a commercial suborbital rocket. With companies like Masten Space aiming for $250 per kilogram to 100 kilometers altitude, I really think this is something we could pull off.

Before we start to do any real design work we first have to think about how to run a project like this. What software tools do we use to design the hardware ? How do we make sure parts designed by different teams are compatible with each other ? How do we communicate and share designs ? Perhaps the first step would be to look at how open source software projects are run. To put it as we say in .nl: "a good start is half the work".

The second thing that came to mind is that to achieve mission success, we need to keep things simple and cost effective. One way to achieve this would be to use off the shelf components, and thinking of creative ways to use them. One crazy idea that popped up in my head was to use MIDI for timing and synchronization.

Last night my mind kept racing and I couldn't stop myself from thinking about technical issues as well I mainly thought of ways how to decide when to open the chute:

• Open the chute as soon as the payload is released from the balloon
• Open the chute after x seconds
• Open the chute at x meters per second
• Open the chute at x meters altitude
• Open the chute at x g-load.
• Open the chute at x meters altitude and y meters per second

I guess the first option would be the easiest to trigger, but also has the highest risk of the chute not opening properly. With the last option you can calculate the dynamic pressure in real time and open the chute based on that. I think this would have the highest chance of the chute opening properly, but also has the highest risk of the triggering going wrong.

Can't wait until first ATLO

[djellison]

I mainly thought of ways how to decide when to open the chute:

Balloon
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Chute
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Gondola


Balloon bursts - chute opens automatically - couldn't be simpler. It's worked for hundreds of amateur HAB's.

Doug

[nprev]

Really! What kind of sensor is used to detect the balloon burst? Only things I can think of are some sort of tether tension cell (like a maritime winch) or an indirect acceleration measurement from an onboard nav system. Would be interested to know the actual method, because both of these techniques seem pretty awkward.

[ElkGroveDan]

Really! What kind of sensor is used to detect the balloon burst?

A sudden acceleration of -9.8 m/s/s is the triggering signal. When that force is applied on a (now) untethered gondola there will be (relative to the gondola) an upward movement of air that will inflate the parachute.

I tried to take out a patent on it in mine and Doug's names (using Doug's diagram) but apparently its been done before.

[JRehling]

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[djellison]

The 144.8 Mhz FM APRS kit arrived. I need to get a 10mw radio module for it ( pin compatable swop out coming soon ) - but it WORKS.

This is the module just sat on my desk, the gps rec on the window - and my Icom IC-R5 listening in with an audio cable into my PC using 'Packet Engine Pro' and AGW Tracker. Couldn't BELIEVE It worked first time! Screenshot of the first lat-long coming out of it attached.

Just turned it on again - slightly updated Lat Long this time - and plugged the GPS Coords into Google Earth. It's REALLY working. That point is the corner of this garden - <10 metres.

Doug

Attached thumbnail(s)

 

[ElkGroveDan]

This is rapidly becoming my favorite topic.

That is so cool Doug. Gotta get me one of them things.

[djellison]

Tonight I'll try and do a little vodcast thing about all the stuff I've got and how it's going. When the packet watch came up and 'NOCALL' appeared - I actually punched the air and screamed "YES! - NOW we're on the way". Need to get a serial cable so I can tweak the MiniTrak's settings.

Doug

[AndyG]

Can't beat a few Ents at the end of the garden.

Meanwhile, how come the unit returns a course (82 deg) when there's no speed?

Confused, Andy

[djellison]

Well - the course remains once you're stopped I think (technically, it would then become a heading rather than a course0- and as it got more sat's ( it was stuck up against the window to get sat visability) it updated the location, so the motion from the first rough position to the later more accurate position was 80ish degrees ( which, in retrospect, is about right - the first plot was SW of the later one.)

Doug

[marsbug]

The only contribution I've got to make to this is enthusiasm-so here it is: GO DOUG, GO BALLOON!