Dec 122010

I have been a fan of weather and storm watching since I was a little kid. It really all started one night when I was in bed in the midst of a wild thunderstorm. I was awake and frightened and thought everyone else was asleep. I heard a noise, and as kids do when they can’t sleep, I went in search of what I was hearing. It was my grandmother. She was standing by the sliding glass window watching out across the lake. I went and stood next to her. I told her that the storm was scaring me. I asked if it was scaring her. She said no. She explained how she loved to watch the storms. We sat there together not really saying a whole lot, just watching the storm. Occasionally we would comment about the lightning or thunder hits. I forgot to be scared. It turned out that I wasn’t. I was amazed.

I have been in many storms since. I have been closer to tornadoes that I would have liked. But all in all, I am still fascinated by the storms. Since I started learning about the mircocontrollers, one of the earliest ideas I had was that I could somehow use one to measure the weather. Early on I did not know how to go about it. But as I have been exploring new areas of technology, as well as learning to build, building, and crafting new things I am starting to understand more and more what can go together. It is somewhat freeing actually.

So, weather. Where to begin. Starting with my most basic needs, I need to know how fast the wind is going and from what direction. I decided that I wanted to build an anemometer. There are several folks on the web who have built them, but true to form, I did not see one that sort of suited me. (What can I say, I like making my own stuff). So, I started to play with different ideas. I still had several skateboard wheel bearings from the windmill, but I have found that those will rust when exposed directly to the elements. I could use them, but they would need to be shielded. I wanted to integrate electronics so I could measure the speed. I wanted it to be cheap. I wanted it to be repeatable in case I wanted to do it again.

PVC is a great, low cost, experimental building material. It can be cut, shaped, sanded, and painted and put together in countless ways. It’s like Legos for Adults. The way I decided to approach it was to have a cap suspended on top of a smaller cap. The outer cap would need to freely rotate, yet stay connected to the inner cap. An issue I ran into was how to drill a hole in the exact middle of the pvc cap. I have no good scientific answer. I used a ruler and marked lines across the dome. I kept doing this from many angles till one spot showed it’s self as the center. I used a 1/4  2 inch brass bolt. I used brass as this is what they use in toilets and figured it would be outside.

The bolt was put through the end of the cap and nut tightened in place. Before I get too much farther, I should mention that I fit everything together to make sure it all worked then went back and epoxied all the non moving bits. I drilled a hole in the middle of the smaller cap and widened the hole until the ball bearings fit snugly inside. I put the outer cap over the inner cap and added another nut to the inside of the smaller cap to hold the two caps together. The 2 nuts sit directly on the inner rim and not the sleeve of the bearing. Being that the outer rim is firmly attached to the smaller cap, the inner rim spins freely. BTW, something that I did not take into consideration was how to hold the nut as I was tightening it. There is no room for fingers in that small of a space. Needle nose pliers helped out here, but it still was not easy. If you are asking why, remember that the tighter that the nut gets, the further down the large cap gets, which means you have nothing to grip onto after a while because the outer rim spins.

The next issue I needed to figure out was the scoops. I have seen all sorts of ideas ranging from as simple as easter egg cups to folks who have custom machined their own. I wanted something bigger than easter egg shells and far less complex than machining. I could use a makerbot and make whatever shape I wanted, if I had one (Man oh man, I want a makerbot).  One day when trolling the dollar store (a good source for budget makers) I saw a huge display of big plastic spoons. After being an ass and asking how much they cost, I bought 4 of em’. I bought 3 for the build and one to goof up. Not long later, I had the handles removed and ready to attach.

I used super glue at first, but it really did not work well. Epoxy eventually was the right solution. But how does one hold a salad spoon to a round spinable object until it hardens in place? You get comfortable because you are not going any place for a while. With all the goofy angles, there was not a good way to clamp it. Fortunately is was 5 min. epoxy.

For the electrical part of this, I took apart a relay I had in my kit o goodies. If you gently pull on one of the ends of this variety, the glass reeded vial will come out fairly easily. I soldered wires to the leads and covered them in heat shrink to keep the water out. I epoxied the reed to a groove I made on the outside of the inside cap. (clear as mud?) I drilled a hole in the side of the bigger cap just big enough to push a little magnet into. The magnet trips the reed which gives you your pulse for your uC (microcontroller).

The wind vane was dome somewhat similar. But, to make the assembly a little easier (which occurred to me after putting together the anemometer, I bolted in reverse this time. I had the bolt come out of the top of the big cap. Something I did not realize when I started on the arrowish part of the vane was that the 2 sides had to be of equal weight. Who knew. I cut it all out and epoxied it to the cap. It was locked in and when I went to test it, it sort of lazily flopped around, but did not really head into the wind as I had expected. I am writing this some time afterwards and seriously have no idea how I solved this one, but I found that balance was the key. I some metal bits, but it was not enough. I started looking for small, really heavy stuff so I could balance the thing. I remembered the fishing weights we had used for the pinewood derby cars. I cut a slit down the middle of a large weight and epoxied it in place. The vane came to live. While it is ugly as hell, it effortlessly moves about when even the slightest wind is present.

 Posted by at 10:21 am
Jun 132009

I have been interested in natural energies for a long time. Even back before it was the cool, “in” thing. I am being a touch snarky as I hate how the media can dictate a fad. “Red is the new orange” and all that. I guess this is not really the point is it? So, yeah, I have been interested in natural energies for a long time. I used to live in California. There was a rather steep hill in our back yard. From the top, I could see the wind farm that was close by. There were so many great shapes and methods of working. If you drove east, there were stretches of  windmills that went on for miles. They were so massive. I think that this was some sort of testing ground as there were the traditional designs in a variety of forms. But then, there were these oddball designs unlike I had ever seen. They looked like a bastardized carrot peeler stood up on end, and a big one at that. These things captured my imagination. They were VAWTs or Vertical Axis Wind Turbines. It was not immediately obvious how they worked. We moved from Ca. and I quickly forgot all about them.

A couple of years ago we went to Disney World. Walt has always been one of my inspirations. Here you have a guy who wanted to build cool stuff, and needed a way to fund it, and more, a place to put it. So he creates Disney Land. The day we went to EPCOT, I saw all sorts of windmills all over the park. They were used as more moving sculptures, not as electricity generating devices, but they were beautiful. They moved so effortlessly in very little wind. This was my spark.

When we returned home from DW, I went in search for info on windmills. Initially, I was reading about horizontals. I did not know what to name the verticals. In my mind they were just windmills.  I checked one of my web hang outs “Instructables”. There were several DIY how to’s. Some had links to YouTube vids. After watching the vids, I was lured into other streams of vids. I traveled up and down all of these little bits of education, trying to scrape just a little more detail that someone else had left out. This seems to be my pattern for new interests. Eventually I found that they were called VAWTs (vertical axis wind turbine). I finally had a name to put to the thing. You know, as far as acronyms go, VAWT just looks intimidating. Right? Oh… never mind.

I started looking for a design to settle into. There are so many great ideas out there. Some that were super simple to rather complex and overly engineered. Hmmmm. While I do appreciate overly engineered, I did not want to go too crazy right out of the gate. There’s plenty of time later for that. Right now, I needed a proof of concept for myself. I am sure I have said this elsewhere, I do not like to make a photocopy of someone else’s idea. If that’s all I was interested in, I might as well just go out and buy one. I saw a post somewhere about Jay Leno. Apparently he is very interested in all types of green energies. This video shows one of his earlier windmills. It is built by a company called Enviro Energies.

Edit: The video is no longer available as the company has gone out of business, link removed.
Update: Someone put the video on youTube with another company name on it, so I am linking to it again.

The shape of that windmill was well within my doing. It was head out to home depot in search for metal that would not rust. I found some galvanized flashing sheets. I got 2 sheets for $6. I would not supposed to though. When I went to pay for it, the lady said that it they would be 28 dollars. I told her that it was $6. We went on a walk back to the shelf where I found them. Apparently this was the price of an old item and had not been updated. She said that it was their fault and gave it to me for the price that was listed. Woohoo!

I used only one sheet of the flashing, cut it into 4ths with the angle grinder. I had some PVC tubing in my garage. I cut a small length. I drilled 4 holes at 90 degrees to each other (eyeballed), and attached the sheets with rivets. The trick here is precision folks (insert snirk here). I am sure that there was some serious math taken into consideration when Enviro Energies were developing their model. Aside from trying to keep the thing balanced, this thing was built on the fly. It was a rough draft. I wanted to see it work before I put mass amounts of energy into it.

I used several lengths of all-thread to hold the blades in place. I decided to keep the full height of the blades unlike the blades on Jay’s. There very well may be a reason to swoop them off like that, but it seems like you would loose too much surface. I purchased some bearings off eBay. These fit perfectly into the PVC tubes. I scrounged the center shaft out of an old printer that my son and I took apart.

I like the idea of mag lev to reduce friction. I went out to ACE in hopes to find some magnets. I found some fairly decent 60lb. magnets. I super glued a set of bearings to the center of the magnet cap. I placed the magnets on the shaft. I put the windmill on top of that and it floated nicely. Very cool! To get some extra height, I set up a ladder on our back porch. I set the windmill on top of it, and used a ratchet strap to secure it in place.

It works great. In wind that is barely perceivable, it just spins. It is not super fast, but it is continuous. This one was not designed for electricity. Again, it is a test of design (or lack there of). The next one will be larger and placed on something a lot higher. It was quite impressive to watch.

This post ends with a small bit of bad news. We got a storm one night. I love storms and this was a good one. The wind was fairly extreme. I was in the kitchen and had not thought about the fact that the wind mill was up. I heard a sickening whomp from the back of the house, then about a second later, a sad little clang. I ran to the back porch and found that the ladder was there, but no windmill. The ladder on it’s side leaning against the rail. I went down stairs, and into the back yard, and there lay my poor little windmill in a heap of bent metal. It was sort of funny, and sort of sad, but more funny.  I am excited about building another one.

SAFETY NOTE: (Both galvanized steel and the disks from the angle grinder can produce substances that “may cause cancer” in the state of California. It is what the label said. Now, I am no genius, but I have a hunch that it might also be harmful in other places too. Hmmm. Seriously though, be safe and wear some sort of respirator, or at least a face mask if you are using this stuff.

Edit:(New Info) – I have recently found some info that states that friction reduction via mag lev may actually not be helping that much. It appeared to make things run more smoothly on mine, but I have no real way of testing aside from what I saw visually. The article I read had all sorts scientific proof blah using all sorts of crazy high math blah blah, with all sorts of clever symbols found in the reverse engineering of a UFO tech in Roswell. Ok, I admit it, I suck at math. I do pretty well when I have something to apply the math to. I tried to follow this guy, but come on… Really?  So I have not settled into a new design yet.

 Posted by at 8:32 pm