3D Printed Ice Structure

If you're local to me, you will have noticed it rained a lot earlier in the week. And that it was very cold last night.

Well. It appears somebody didn't cover up the sandpit.

While amusing, this is not what this post is about though.

This is:

This ice structure is poking out of another outdoor toy that wasn't covered up.

How did this happen?

It looks like a triangular shaped ice tube. It may not be too clear from the pictures, but the walls of the structure are made of ice and the inside is liquid water.

I imagine that due to the temperature the water under the ice needs space to expand and pushes up through what must have been the last small opening. Each time the water pushes a bit higher the edges freeze, constructing the walls layer by layer - a bit like a 3D printer might do it. Whether this is actually what happened I don't know.

To check that it was actually ice, I tapped against one of the walls and it came crumbling down, spilling some of the liquid it was holding back.

[UPDATE 30/11/2012 17:16 GMT]

Apparently, this is called an ice spike and they don't happen often in "non-distilled" water - making me feel all warm and fuzzy that I found one in our garden.

Motion Detecting Bird Feeder Cam

It has been snowing quite a bit recently so despite never having had much success with the birds, I decided to put our bird feeder out. It is hanging from a washing line, well away from any structures that could hide predators. Well, once the snow lady has melted it will be.



Reading and watching Oli Wood's bird feeder webcam inspired me to dig out our "old" digital video camera as well. Our camera is a Canon MVX350i, which has 20x optical zoom, just what's needed to be able to zoom in on the bird feeder at this distance.

The camera is connected to the computer using a Firewire cable, and once I had figured out how to switch off the "auto power save" feature we were good to go.

The camera is directed at the bird feeder using this expensive hand optimized stand:




Because we always only get very few birds on our feeder, I wanted to use motion detection webcam software to take pictures of any birds coming to the feeder. I vaguely remembered a friend using software that took pictures when it detected motion and uploaded them to an ftp server. I don't remember what it was called and hence had no luck finding it.

I did however find open source surveillance software iSpy that appears to do the trick.
Whenever it detects motion it records a bit of video up to a certain length. It has a few settings to change the motion detection and its sensitivity.

The first day I had it running it took a nice bit of video of what I believe is a robin, but completely missed the pair of tits that appeared on the feeder a few minutes later.

Increasing the sensitivity - I think I was increasing it: the slider doesn't mention which we is up or down, so I presume left is down, right is up - only seemed to get me lots of video of the wind blowing the feeder about, so in the end I stuck to the default sensitivity.

It would probably be better to make sure the bird feeder is rigid by sticking a pole in the ground and up its bottom, and increase the sensitivity. The pole should stop the wind blowing the feeder about, while the increase in sensitivity should pick up even the most delecate of birds.

One nice touch is that iSpy buffers the frames, so that when it detects motion it can use a bit of buffered video so you get all of the action, and not just the bird disappearing. It would otherwise possibly have missed this coal tit flying in:



The video of the robin is unedited. I trimmed about a minute of feeder waving about off the end of the coal tit one.

Star struck

John reminded me just now about the first time I saw a hummingbird in real life. Where I come from you only get them in nature programmes on the telly, not outside hovering near flowers. I don't think I ever realized where they do appear in the outside world, so when I saw one I was absolutely star struck: "Look, it's a hummingbird, off the telly!". I was in a suburb of Goleta trying to find the local supermarket on my first day there, and noticed a couple of really really big "bees" hovering above a tree, about three meters above the ground. Imagine my joy when I realized I was going to see them most mornings having their breakfast outside my kitchen window.

I had a similar experience years later (a couple of years ago now, blimey, I'm not getting any younger) when I visited the Grand Canyon and noticed a big vulture sitting below us. Someone uttering "condor" made me forget about the Grand Canyon ("just a big hole in the ground after all") and stare star struck at the condor. "Look, it's a condor, off the telly!". Apparently some California Condors I had seen going nearly extinct on the telly had been moved to the Grand Canyon to thrive.