I am sure
there are many ways a remote controlled aerial camera
could be made. For simplicity, the scope of this project
was limited to something that could be lifted into
the air by a large helium balloon.
I have
seen some people go to great lengths designing sophisticated
helium balloon powered cameras with parachutes and
GPS locaters to track where the device floats to.
However I felt it would be nice to try out something
a bit... well.. less advanced.
How's this
for a simple setup? A helium filled weather balloon
for lift. A long length of nylon wire tied to the
balloon to facilitate retrieval. An old film camera
modified for remote control. Too easy?
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Started
with the transmitter/receiver unit to enable remote
control of the camera.
To the left
is a 4 channel remote control kit that I put together
- kindly supplied by Oatley electronics.
Pictured
is the receiver unit, and on the right is the little
transmitter unit with four buttons (one for each channel).
Talk about channel overkill. |
Unfortunately
I'm never up for taking photos at the start of a project,
and so I don't have any photos of the camera in its
original state. But modifying this beast was an interesting
task...
I'm
not a mechanical engineer of any sort, so it took some
fiddling to install a solenoid onto the film camera.
This had to be done to replace the original shutter
button because there was no other perceivable way of
opening the shutter remotely.
In
the picture the RC unit is hooked up with the modified
film camera with the solenoid just visible (follow the
pink wires). |
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By now
I had decided that an a film camera was probably a pretty
bad choice. So many moving parts always ends in tears.
But it was the only thing which I could easily obtain
so... nevermind.
But weight
was immediately to become an issue. Along with this
sexy foam box, the whole payload weighed 400 grams...
I had already bought a weather balloon - with a maximum
carrying capacity of 250 grams. |
This balloon
was a 100g Totex Meterological balloon, bought from
Ebay. It had a recommended inflation size of 0.8m
in diameter, and a bursting size of 1.5m in diameter.
Some number
crunching meant that if I pumped the balloon to 0.8m
radius, the helium would lift 350g, less 100g for
the balloon itself, so 250g. But if it was pumped
up to 1.2m radius, it would sufficiently lift 450g
off the ground. Maybe... just maybe??!!
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Totex worker moulding a new balloon
Image
courtesy of Totex Meterological
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So that
was the magic number, 1.2m.... until a new complication
arised. The helium cylinder only had enough helium to
pump to 1.1m radius. That meant dangerously close figures
for balloon lift and weight of the payload. Anyway,
we will see...
And
so this goes to show, everyone, that planning is a key
part of any project. Something I hope I have finally
learnt. Hmph. |
Up
to this point in time, I'd also forgotten that the string
used to secure the balloon would also weigh alot. Some
scrounging around in Big W found a 1000m roll of nylon
wire, with a tensile strength of 5.4kg. It was light,
strong, and definately perfect for the project. I had
this new idea of attaching tags onto sections of the
string to indicate altitude.
And
so I started unwinding..... |
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An altitude
indicating tag was placed on the string every 20m, all
the way up to 1000m. As you can probably imagine, this
took a HELL of a long time.
To the left
is a picture of the fully unwound wire. I had set up
an unwinding system consisting of a chair and a pole
to hold the wire. Probably just as technologically advanced
as the actual camera device itself. |
And what
comes unwound must be rewound... and so the long process
had to be done all over again. Fun times.
Here is the
finished (but rather messy) roll of string.
Now almost
ready for liftoff! Check out Launch
I for what happened on the day. |
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