An umbrella made of telescopic capillaries and alginates. The handle and the ribs are made of elastic rings of capillaries in tapering tubes, and the canopy of a concertinaed layer of alginate. As the air gets damper, the canopy absorbs moisture in the air and becomes more flexible and elastic and expands. This change in consistency acts as a fairly reliable predictor of rain, like seaweed. It can then be kept outside in preparation for rain. Once it starts raining, it can be dipped in a puddle handle first. Capillary action pulls the water up the handle, causing it to swell and expand vertically and horizontally. The horizontal expansion pushes the segments of the handle and then the ribs up and out. During dry weather, the umbrella shrivels up and shrinks until needed again.-- nineteenthly, Mar 01 2009 Rainwater collection seen from orbit http://i122.photobu...enthly/domicile.png(Fairly rare to do that, i admit) [nineteenthly, Mar 01 2009] Bun if I can fold it up without the use of a battery-powered hair dryer.-- placid_turmoil, Mar 01 2009 OK, well sprinkle it with some kind of desiccant, for instance ordinary salt, caustic potash or silica gel, and it'll collapse.-- nineteenthly, Mar 01 2009 I envisaged propping it up in the corner while it collapses. Right, so there's another way. There could be a pump to remove the water, or it could become flaccid by transpiration. Alternatively, collapsing the umbrella could squeeze out the water into a bulb through a valve. Concerning dirty puddles, that needn't be a problem as such because you screw in a handle later. You don't actually touch any of the muddy bits. There's also such a thing as foresight. If you look at the linked picture of our house, you will note a series of vaguely rectangular blurs in the back yard. Those contain clean rainwater filtered through pieces of fabric. All i'd need to do is go out and dip it in one of those. Not everyone stores large amounts of water in their back yard of course.
A bigger problem might be stopping grid from clogging the tubes, but they could be covered in a fine mesh, or indeed be a fine mesh.-- nineteenthly, Mar 01 2009 random, halfbakery