I tried building a few pieces of wind art. The most successful creation was one of the simplest to build. This was my first attempt at using a bicycle part. It was quite quick to make – perhaps a couple of hours.
I cut a bunch of identical rhomboid shaped pieces of galvanised iron sheeting to wrap around the spokes to catch the breeze and make it spin. There is a slight bend in each to make them fit the spokes as the adjacent sides of each piece wrap around are not parallel. I thought I would have to use some additional fasteners to hold them in place but simply tapping the folds down with a hammer has been enough to keep them tight for over 10 years during some pretty strong winds.
I used an old hardwood garden stake to fasten everything on to. I used a metal tube on an earlier one I built with an old desk fan blade and it was quite noisy and swapping to timber made it quieter, so I went with that again for this one. I’m not sure I would do the same again. If I did use timber I would use thicker timber. Although this Australian hardwood is quite tough for size. Notice the lichen that is growing naturally on it. The tail is just another piece of galvanised iron sheet.
I made a bracket out of a short piece of angle iron. Two bolts hold it on to the timber.
The pivot point is quite basic. I don’t think I would use this method again even though it has worked quite well. I cut two pieces of steel that were the same width as the timber and drilled three holes through the steel and the timber. The timber is sandwiched between the two pieces of steel and held in place with two bolts through the outside holes. Grease was pushed into the centre hole. It turns on a bolt which rubs on the steel plates as the timber would wear out quickly without the steel. The whole thing mounts on a bolt that is fitted through a hole drilled in the end of a pipe end cap.
Every couple of years I top up the grease on the pivot point and clean and re-grease the wheel bearings. This keeps it running quietly.
Last week I bought one of those new Raspberry Pi computers. It is a small single-board computer about the size of a deck of playing cards. It was developed in the UK by the Raspberry Pi Foundation with the intention of making a cheap computer to be used in schools for teaching about computers as opposed to teaching about Word, Excel and other applications.
There are two main versions. The one I got (and I think the most popular) is the slightly more expensive Model-B which I bought in Australia for about $38.00 (without SD card). While it doesn’t look like it could do much it has a 700MHz ARM processor with 512MB inbuilt RAM (like those used in some mobile phones), 2 x USB ports, composite video output, HDMI output, a 3.5mm audio output, a SD card slot, an Ethernet socket and a micro USB socket used to connect a 5v power supply. It can run Linux (I have a version designed for it called Raspbian) which is installed on a SD card. All that’s needed to start off is a keyboard, mouse and screen (a TV will do) and a connection to the internet (I use a USB wireless network card). The other thing it has of interest is a GPIO (General Purpose Input Output) header that lets you connect sensors and other things.
The first thing that stood out is the box. It looks like a box of tablets. I opened it up and removed the small circuit board and spent the next 15 minutes admiring it and passing on all the “interesting” facts I knew about it to my wife until I thought she could take no more. The next day when I had more time I inserted the SD card, connected my phone charger as a power supply, a keyboard and wireless mouse and the TV via a HDMI cable and switched it on. Lots of text came up on the screen followed by a prompt for a username and then password. I read the instructions that came with the SD card that I bought on ebay and got the Linux GUI desktop running. I felt like I did when I got my first Commodore 64 computer. I was excited that I could get it to boot and realised that there was so much to learn. Eventually I got an old USB wireless networking stick to connect to our network so I can put that LAN cable away again.
The thing that is perhaps the most exciting other than the value for money it offers is the potential it holds for hobbyists. Already there is a community sharing tips and project ideas. They are cheap… cheap enough that money is not really a reason to avoid using them. Cheap enough that it doesn’t matter if you destroy one and cheap enough that you can buy a few if you want to have several projects going.
So what are my plans? I’m finding the learning curve is a bit steep at the moment and I’m not very confident that I can get very far with it. Initially I want to get it to run as a server and be able to log into it remotely. Next I would like to see if I could connect a sensor or two – maybe a seismic sensor and be able to monitor that remotely. After that I would like data from the sensor to be stored and remotely accessible.