I need a laser for my space program

[Tabish]

Hmm. Ya don't use a laser for this. I doubt the laser will work at -70 degrees.

Here is a simple idea. Why not attach a really long needle to a servo.
I assume you have the ability to send a signal up to the balloon and trigger a servo or something. It can then push the really long needle up into the balloon lol.

 

[Tabish]

EDIT: Double post. My first post took a while to appear, weird...

 

[Krutz]

wow! thats damn impressive!

I would as well use a smashed lightbulb with blackpowder to burn the string. could be as small as a 10mm long thin drinking straw. if its all blackpowder and plastic, you could connect two strings to it, the "cap" in the middle. when it burns away, the strings definitely will be disconnected. with a 1.5v bulb, it will definitely ignite, how low the voltage might ever sag. 0.5v should be enough to ignite it.

do you want to use a rocket as "stage 2" to further lift the cam/payload?
i guess its all timer-based, and not directly (radio) controlled?

how far does the payload/cam drift while falling down? do you use gps or a sender or something to recover it?

really great project! wouldnt have expected some private hobbyist could pull that off!

manuel

 

[Greendream]

Interesting project

Will it be a day launch? Perhaps you could use a solar cell as a power source? I'm not sure if a small one would generate enough current, but it might do, and the sun is more intense the higher you climb.

Another possibility might be a small charged capacitor. Not sure, but I have a feeling they might work at much lower temps than batteries.

Or you could just use a slow burning fuse cut to the correct length and attached to a small charge... or even fuse on it's own if you used it in place of rope/string, depending on what you have in mind.

If you work it out well, I think you might be able to perform both the tasks you want using fuse alone, providing you can find a suitable type of fuse that burns at the correct rate for what you want to do.

 

[pseudolobster]

You can make a simple ignitor by grabbing a filament of steel wool and shorting a 6+ volt battery across it.. The steel will glow red and melt. If you pack the area with gunpowder it'll easily burst into flames. Estes model rocket ignitors are pretty much just this, only I think they use nichrome wire instead of steel.

I actually think you could just wrap a very thin wire around the base of the balloon, pass a heavy current through it and it should heat up enough to melt the latex and just sever the balloon from the payload. I think something like this: 100ft Quality Nichrome Model Rocket Igniter Wire 36AWG - eBay (item 300343386985 end time Sep-06-09 17:52:50 PDT) should serve you quite well.

 

[HIMNL9]

^ but the latex expands, when the balloon rise ..... lowering the external pressure, the inside gas expand, and this may also be 8 or 10 times than at ground level, so probably stick something on latex can risk to break it just when it expands .....

Probably the better thing is use a cotton rope or string for connect the apparate to the balloon, like the ones that are used for DIY candles (not waxed !) ..... just made a mix of potassium chlorate and sugar, dip the part of the rope that you want to burn, and left it dry ..... stick one or two igniters (estes are good, if you don't want to made your own ones, too) in the point of the rope that was dipped in the mix, and wrap with a bit of tape, or some domopak plastic, just for protection against humidity, and all is done