Design and Construction

 

 

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?

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).

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??!!


Totex worker moulding a new balloon
Image courtesy of Totex Meterological

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.....

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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