* Posts by da3andrew

3 posts • joined 30 Jul 2009

Vulture 1: Calling all electronics wizards

da3andrew
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Electronics

"what's the best electronics package to make this thing work."

PIC get's my vote (www.microchip.com). They come in a huge range of models depending on the processing power required, number of I/O pins and on-board perhiperals (including timers, A/D convertors, communications trancievers, hardware interrupts, etc). There's plenty of pre-assembeled break-out boards available so there's no need to do too much soldoring either...

El Reg space paper plane christened Vulture 1

da3andrew
Flame

Release mechanism

If a weather balloon is being used to launch the spacecraft, then it'll pop automatically when it reaches the highest altitude possible. A single-axis accelerometer (plus a microcontroller to do a bit of processing) will be able to provide an electronic signal indicating when the aircraft changes direction from 'going up' to 'going down'. There's a risk that the balloon pop could damage the spacecraft, so maybe the release should simply be triggered by a countdown timer from launch. Or a barometric sensor (e.g., http://www.sparkfun.com/commerce/product_info.php?products_id=8161) could trigger the release at a given height.

The release itself could be made from a piece of string tied around/alongside a low-ohm, low wattage resistor. Apply a modest current and the resistor will be set on fire and burn through the string, releasing the aircraft. Further experimentation will be required to see identify what weight of batteries could provide sufficient current. Failing that, I recall an article in the Anarchists Cookbook (or similar publication) about making an ignition device using a diode taped to a match-head. Once enough backward current is applied to the diode it heats up and set's the match alight. But of course both of these assume that there's enough oxygen at release height for a fire-based release mechanism.

Although not as exciting, a mini solenoid could be an alternative to un-hook the spacecraft from the balloon: e.g., http://www.rapidonline.com/searchresults.aspx?mode=b&kw=&manu=Dialight+BLP.

What is the target height for the launch, btw?

El Reg to launch space paper plane

da3andrew
Go

Balsa != Paper

The use of balsa wood won't make it a paper aeroplane any more! A cleverly-designed cardboard frame should be able to provide sufficient strength.

It could be tough to make sure the aircraft continues to fly (rather than just falling out of the sky) all the way down, particulary with air currents. Making it heavier will help (more momentum therefore less affected by changes in the air around it), but then of course it'll need to be bigger overall to produce the extra lift. Or how about adding some control surfaces and an inertial measurement unit linked up to an autopilot?

On-board photo/video is a must!!!

I for one will happily volunteer my time to this worthwhile endeavour!

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