One of the the worthless cats* woke me up too early, so I ended up re-watching a favorite old film, “A Boy and His Dog“.  It never fails to cheer me up or chill me out!

A minor snip of Wikipoedia on it:

Blood’s opinion of the human race is not generally positive, and Blood is somewhat of a misanthrope. His opinion of humans may have something to do with the fact that Blood is most likely the most intelligent and learned living thing left in the world, and he looks down upon the “stupidity” of humans. In addition, Blood notes that “human sex is an ugly thing”. Blood does however have a more positive outlook on life in general, and believes in a place untouched by nuclear radiation he heard about from a police dog. Blood refers to this place at various times as “Over The Hill” and the “Promised Land“, where “deer and the antelope play and it’s warm and clean and we can relax and have fun, and grow food right out of the ground.” Blood wants to look for “Over The Hill” with Vic, but Vic does not entertain it as a sensible suggestion. Vic states that their current situation is as good as it gets, and there is no “Over The Hill.”

What can I say,  except to mention that:

• • “Harlan Ellison is God” (or at least should be)
    
  • Footage from “A Fistfull of Rawhide” is featured
  • I’ve got to expand that Wiki entry
  • I don’t know another film with both both Jason Robards and ‘Mr. Kimble’ from “Green Acres” in it (please correct me if I’m wrong).

I keep it on the DVD stack next to “Harold and Maude“, “M” and other classic films.

____________________________________________________________
* worthless, that is, until I need an emergency food source.  “The secret is in the marinade!”

(C’mon, you knew I was gonna say ‘Well let me count the ways‘, didn’t you?
All  the outrage that follows is couched in light of the limitations of the WordPress interface.
WordPress is free, so they aren’t disrespecting their customers every moment of every day and
charging them thousands of dollars for it).

So, I’ve been fighting with Mentor Graphics’ DX Designer for the last week or so.  I’d been using Altium Designer previously (and giving them Hell about minor issues, honestly), but the company decided to standardize on Mentor Graphics for PCB design.

I have to say, compared to Altium, using the Mentor Graphics “PADSFlow” (or ‘PADSFlaw‘ as I like to call their abysmal constellation of half-assed software) is like trying to teach a pig to whistle.  The Mentor Graphics product really SUCKS and they know it well (because that is self-evident & I’ve told them so in detail).  I want to share my opinions about it with you (whoever “you” are).  Jesus H. Christ, I get a better user experience with CadSoft EAGLE, the pencil and quadrille paper I was designing with 30 years ago, or even the 80’s version of  “HiWire”  (the very first CAD I ever used).  I could deal with a Windows 3.1 level of user interface, even a DOS 5.0 user interface,  but with DX Designer I feel like my productivity would be better if I was actually PISSING my designs into a snowbank.

The DX Designer user interface is either un-evolved or just plain insulting for starters. Half of the time when I click on the “Help” button it will crash the application, and the times that it doesn’t  the information you need is just not there.  Don’t EVEN bother with the vestigial context-sensitive help icon, it will just open a browser window that tells you to look somewhere else for information.  (This “feature” alone puts Mentor Graphics at the top of my list of nominees for “Death by Mass Rabid Weasel Attack”).  It’s reminiscent of the scene in “Office Space” where they guys are trying to figure out how to launder money by looking up the definition in the dictionary; they found words but not answers.

If you are trying to manipulate a component on a sheet of your schematic but need to rotate it, you’ll need to open a pop-up menu for that component by clicking on one of the pixel-width lines within the component to open the window.  This will likely take you several tries (and that’s after you manage to zoom in on the component, more on that later).  If you are lucky enough to get that darned menu open, then you get to select the “Transform” option, then the “Rotate CCW” option, which will rotate it 90 degrees.  Boy, that sure makes more sense than having a hot-key and a smart selection routine that will grab the component when you click inside its boundary and then rotate it 90 degrees, doesn’t it?  (Please say ‘no’, so the righteous chain-whipping can begin in earnest).

Oh, you’d actually like to connect some components with lines (AKA ‘nets’)?  Here’s another really kludgey part of DX Designer: component pins had better be three grid increments apart or you are going to see your nets do some pretty weird snake-dances on the way (and then they will probably still evaporate like Karl Rove’s wet-dream of a permanent Republican majority after your terminating mouse-click).  Every pin seems to have this mysterious 3-grid “line of death or disfigurement” around it.  Kiss-off your hopes of making a fairly compact-yet-clear schematic in DX Designer or get ready to do the Snake Dance!  (This alone merits the “The Angry Mobs Decapitated Me” dis-merit badge for whoever made this the Mentor Graphics cannon).

Of course, to make a connection you have to be able to see a pin or endpoint clearly, and if, like me, you are working on some middlin’ complex stuff you’ll be needing to zoom in and zoom out at specific points of interest.  Well, DX Designer makes this a “Thing of the Future” by defining “zoom” to mean “zoom to center of sheet”.  Positioning your mouse and using the scroll button gets you a well tempered finger (from Mentor Graphics) rather than a clear view of the circuit element you want to see!  You are going to have to zoom in a little, then fiddle with the scroll bars at the right & bottom of the window, DC al coda.

Say you are working on a banked memory subsystem, with, say 16 each address and data lines (global signals) going to say 8 identical memory devices.  Can you do it one time, then paste copies of all the nets and labels on each memory device?  Not well or easily, unless you copy them off a different page because the idiot DxD product deletes the “global” attribute when you do this within the same page.  Lets count it up: 8 devices times 32 connection, times 4 mouse-clicks to access the local/global ticky-box = carpal tunnel syndrome, high blood-pressure, eye-strain and justifiable homicide.

As Ed Hurlihy would put it: “Time is on the competition’s side when you use DX Designer by Mentor Graphics!”.

Don’t even get me started about the friggin’ “pin files”, the bizarre “HETERO” settings or having to open symbols in MS Word to manually correct bogus default settings and such, the whole “get used to clicking on every signal on your schematic at least 10 times” or the “well, the ’save + check’ function just barfed a lot of errors, but the error messages in the little  window aren’t linked in any way to the general region of the ‘note’, ‘warning’ or ‘error’ (so if DX is whining about something related to an oftentimes irrational default / invisible attribute conflict you don’t have a prayer of making use of the worthless Mentor Graphics product to find it).

Mentor Graphics is just a waste of time, spontaneously trashing designs.

Hint:  if DX Designer decides to screw up what you are doing…. just delete all the connections, labels and properties you can, then start over again (and again and again…) — it will take less time than finding the source of the problem {eg, your initial purchase decision} and correcting it.

DX Designer is the least capable and most infuriating schematic capture system I’ve used since 1982, bar none.  If you see it coming at you, SHOOT TO KILL or it will steal all your ‘essence’, defile your women, stampede your cattle and give you the Clap.  Yes, DX Designer is that unclean.

At several thousand bucks per seat and in light of the ‘issues’ built into the product (and I can only conclude it was with malice aforethought), if you don’t end up wanting to sue these bastards for gross negligence and misrepresentation, you deserve every bit of malfunction you’ve paid for (Duwane, I hope you are reading this!).

Mentor Graphics should be debarred from selling inside the USA just on the basis of the lack of a usable help system (it sucks so bad only to encourage you to buy their “training seminars” is my guess), the finicky non-response to selecting a net, bus or component, the poorly documented features (like refusing to recognize lower case pin numbers), the really cool way their software crashes leaving your design in ruins and their contemptuous license system (you want to be able to actually look at your CAM output… well, that’s an additional charge, you understand!  Sure, Pads can place/orient parts on a radial grid… but only one at a time, unless you give us even more money… and the blood of virgins, MWUAHAHAHAHAHA!).

Mentor Graphics as a whole, and DX Designer in specific, is either an EPIC FAIL or an EPIC ABUSE (or a continuing criminal enterprise), I can’t decide which.   It is hard to imagine this level of incompetent applications programming (after all these years), the product’s user unfriendliness and unwieldiness and the level of corporate “up yours, Bud” attitude that this product radiates as being anything except an embodiment of everything that’s going wrong in America right now.  Bring in the guillotines!

Does Mentor hire anyone that’s NOT a psychopath bent on destruction? Companies that put out this kind of excrement need to be shut down and their executives and managers blacklisted.  This gang has turned a once pretty okay product into crap, and nobody should pay them to do that again: they should be sentenced to screwing up orders in a fast food restaurant where the angry customers can call them personally to task for their sins, forever and ever amen!

If Mentor Graphics was located in my city, their executives and managers might suffer a much higher than normal rate of unfortunate “accidents” involving falling masonry, flammable substances or large object forcibly inserted into their rectums (as a warning to all who dare follow the ‘Mentor Graphics path to the Dark Side’).  These kind of sub-humans need to have their birth certificates savagely revoked: they steal from all Humanity, even while knowing better.  At this moment Mentor Graphics pisses me off even more than what’s left of the GOP KoolAid mixer/drinkers, the Birthers, the Birchers, the Klan and all those other of wastes of protein:  fuck’em all unto death, I say!

Don’t waste your money or time using Mentor Graphics products, gang!  Save yourself a lot of aggravation by sticking to almost any other product on the market:  it will be just as capable (if not more so) and lots less buggy… or wait for the wintertime, drink a lot of coffee and get your aim honed for action.   You’ll be glad you did.

Some free advertising copy for Mentor Graphics and their DX Designer ( I hearby formally and legally renounce to all parties and for all time the use of the following text by anyone including Mentor Graphics (may their nipples crumble into crusty bits in very public places and to their great displeasure, just because they deserve it for vending such UTTER CRAP as USABLE PRODUCT,  PraiseBob!):

• Mentor Graphics: more SUCK for the buck!
• I just love not being able to zoom to a selected location by default, that’s why I use DxD!
• DxD: Couldn’t we have beaten the ‘outsourced’ people harder to get a useful product?
  
• DxD: where even clicking on ‘Help’ can crash your system
• Dude, it’s totally ‘rad’ and ‘totally random’:  DxDesigner!
• You’ve got time to guess for a living: DxDesigner!
• Tear up your work and do it over again because you use Dx Designer!
  
• DxDesigner, from Mentor Graphics… because the other packages enhance productivity!
• You don’t hate life enough?  Try DxDesigner by Mentor Graphics, it’s ‘Craptastic^©‘!
• Death by a thousand mouse-clicks: Dx Designer?
• When I deleted this component all the buses and signals disappeared, too!  Dx Designer will blow you away!

Personal issues , 100+F degree weather, an SBIR proposal and an article for “Steampunk Magazine“ (as well as my investigation into low-tech hydroponics)  have had me offline for a bit… (it’s an ADD thing, hope you understand).

I’m re-tooling a different low-tech wind energy approach now, and working on a small-scale “smart grid” application, but expect something on methane digesters ‘real soon now’ (with typical low-tech, ‘tinkerer-sans-garage’ appeal).

As ever,
Offlogic
26 July 2009

I finally got to play with PurEtch, a photopolymer etch resist film sold by Cape Fear Press.

It’s easy to use and uses no toxic chemicals: laminate it to your copper/other metal plate under “bug light” (the process is similar to applying sun-shade film to a window), dry it with a hair-drier, attach your transparency artwork, expose to sunlight (about 12-16 seconds at noon), then wash out the shadowed part with soda ash/washing soda solution and etch (see Cape Fear Press site for videos).

Instead of electro-etch, I use H2O2/muriatic acid at 2:1.

First impressions:

1. I’m still not up to the repeatability I’ve achieved with toner-transfer.
2. I think I’ll like this stuff once I get the hang of it.

The two recurrent problems I have (besides working hurriedly to keep cats/dog/family from flipping the lights on in the kitchen) are heating the plates/resist long enough to get the water out (I ruined first plate by over-heating), and leaving it to develop fully (I keep pulling it out early, then battling a transparent residual mask).

I’m sure this will get better as I gain familiarity/confidence with the new resist.

This is my favorite cartoon (like EVER) by Bernard Kliban [my early working years were haunted by this image, really].

From Wikipoedia:

“In 1962, Kliban became a Playboy cartoonist, contributing cartoons until his death. He is best-known for the book Cat, a collection of cartoons about cats drawn in Kliban’s distinctive style. The cat cartoons were discovered by a Playboy editor and the 1975 book Cat was born. This led to several other books of cartoons ending with Advanced Cartooning in 1993. Since Cat, his cartoons have adorned many products including stickers, calendars, mugs, and t-shirts.

The books that followed Cat consisted mostly of extremely bizarre cartoons that find their humor in their utter strangeness and unlikeliness. Many of these are cartoons that Kliban drew for Playboy. They often contained dysmorphic drawings of nude figures in extremely unlikely environments, as if to spoof Playboy’s own subject matter. Kliban also had a recurring series of drawings called “Sheer Poetry”, in which the page would be split into six panels, containing random images of objects whose names, when spoken in the order presented, would form a rhyming, nonsensical verse.

According to Art Spiegelman, Kliban invented the form of cartoon, popularized by Gary Larson and others, of a single panel with a third-person caption describing the action”.

To William Burroughs, wishing that he was still alive.

Thanksgiving is good, not all dark, but in memoriam of a lot of good things, gone like water under the bridge:

Thanks for you, Bill.
You are missed.

Odds & Ends
Odds and ends make up the majority of my bills ‘o’ materials, with most materials very cheap if not free.

Yes, certain “consumables” do require expenditures at the drug store or beauty supply (hydrogen peroxide, acetone), hardware store (muriatic/dilute hydrochloric acid) or (in the case of copper-clad PCBs, semiconductors and more “interesting” chemicals) even ordered in from the internet.

Still you can have a lot of fun by just becoming a “rational pack-rat”.

Maybe it’s the thrifty Scots-Irish genes on my mother’s side, but face it: junk is fun and very useful!
Recycling is very chic these days.  Remember: it’s only garbage is you don’t make use of it.

I’m not talking about old car parts type junk (though I wish I had space for more of that), I’m talking the more mundane items of everyday life that are free for the storage space.

Containers
I am a container freak, I admit this freely:  pill bottles, film cans, margarine tubs, the little plastic cases that doodads come in. There is nothing so useful as an appropriately reusable/disposable container. (Did you know that PET plastic pop bottles will turn into little gloopy boogers when sulfuric acid hits them? Know your plastics!).

Dead Appliances and Electronics

Wall Warts
I never throw away a wall wart, EVER!!! I’ve got a drawer of them, most with the plugs still attached. There are so many plating, etching and hydrolysis experiments that require you to pinch off just a little bit of the power on the Grid that I’m sure most of us would go to Hell for wasting such a resource.

Dead Circuit Boards
Always have a few sacrificial circuit boards (from a dead UPS, say, or last year’s VCR/DVD) around to play with.

Organ Donors
When your weed-whacker dies, keep the motor, switch, power cord.
Become a recycling Ressurectionist, a ‘Knox-doctor of Appliances’, a ‘Parasite of the Disposable Culture’.

My favorites are cheap inkjet printers. They usually cost less than a set of replacement cartridges, and every one of them has a power supply (usually external/wall wart), a stepper motor, a “regular” DC motor and at least one photointerrupter-type paper edge sensor.

A real “Cannibal Commando” can come up with at least a dozen ways to use parts like this to start his new Warlord Kingdom: “Every Person a Monarch, Every Home an Embassy”.

On Amateur Science

If you want to explore bad enough, you will. If you are lucky, you will find the tools &  supplies you need (beakers and stuff show up at brewing supply shops, I find) and hopefully, someone more experienced to influence your efforts in positive (not getting ARRESTED)  direction.  Mayhaps you’ll found the next Bose or Intel?

These  are the best of times and the worst of times. Drop me a line if you can find a chemistry set with anything stronger than dilute ammonium hydroxide solution in it. Then go to the grocery store and buy a pound of “household lye”: the world seems immune to irony, no?

I read the other day that prescribed drugs caused something like three times as many ODs as illicit narcotics… but don’t let me get on any soapboxes. I just LOVE Big Brother all over the place, in every mathematically conceivably way and every chance I get.

Whenever I check my blog traffic, I am amazed by some of the search terms I see (“steampunk babes”, “does water effect a zinc penny”, etc).

I’d love to give you answers to some of the questions not explicitly covered in the blog already, gang, so just email or comment me, and I’ll tell you/find out what I can share.

This blog is all about DIY. The more Doers/Makers out there the better I like it!

[Updated 02April09]

[Indian Territory is returning to temperate conditions for a few weeks, so I'll be able to continue the windmill work: hooking up a genny to the 75 watt S-rotor, refurbing the break-down HAWT, etc.  Lots of stuff's been going on lately, sorry].

What the… a portable windmill?” you may well wonder.
Well, my thinking is that I can’t make a very effective photovoltaic panel in my workroom, windpower has a lower cost per peak watt than solar panels, and I know I can make a windmill (see the Otherpower website).
The projected application is for emergency power (we had this ice-storm, see, and we were without power for 10 days, yeccch!) in a knock-down form that is easily stored and transported. I figured portability and cheapness would be ideal for disaster recovery and remote operations (I know this guy that does the ham radio emergency communications thang) and, hey, “infantry portable/field maintainable by indigenous personnel” has gotta be a plus for just about anything, right?

Besides, windmills are cool, especially if they are funkily home-brewed.

While perusing homebrew windpower efforts on the web, I came across an interesting approach by “Cowboywindmillbuilder” in his Instructable . Some of the key inspirations contained in his design were:

• Cheapness and simplicity
• Semi-rigid, fabric covered blades
• Downwind design
• Using a 90 degree drill adapter to bring the torque to ground level

Cheapness, simplicity and portability would be impossible in a high-tech, high-efficiency system, so in my homebrew system moderate efficiency and simple construction (and did I mention cheapness?) were my goals. [Cheapness and simplicity are, of course, requirements of anything (and anyone) that I do].

One strength of a downwind style windmill is eliminating the need for a tail, that part acting like a weather-vane to keep the prop turned to the wind. The drag of the prop, mounted on the “down wind” side of the pivot is enough to keep the blades facing the wind. Some efficiency is lost from turbulence around the mast, but that’s just pocket change in the bottom line. Lower weight and simplicity will make up for this.

I’m breaking this project down into several sub-tasks:

1. Hub/Blade assembly
2. Alternator
   • Coils
   • Wiring scheme

Making the Hub (Method 1)

I am fortunate to work at a company with a large variety of shapes and sizes of scrap aluminum and steel left over from the water-jet machines. Many of these pieces are mild steel and circular. I found a few 8- 3/16th circles of 3/16th steel that seemed perfect for my project. I marked the center (using basic geometry constructs) then used a protractor to mark the circle off in 12 even angular divisions, like a clock face.

To hold the 1/2″ plastic conduits for the leading edge supports I purchased a set of three 3/4″ set screw couplings for metallic conduit and attached them at 4 hour intervals around the upwind side of the hub. This scheme should make balancing the blade easier, just loosen two screws and fiddle around with the protruding length.

To hold the fiberglass rods for the trailing edge supports I purchased 3 steel 1 x 3/8″ pipe nipples. I used a flux-wire welder to tack these on the downwind side of the hub at intervals 1 hour behind the conduit couplings. I added a little bit of weld to the open inside ends of the nipples to act as a stop for the fiberglass rods.

The hub, all welded up (by the worst welder in the world)

Making the Blades

For small wind turbines, there is a delicate balancing act between the lift and drag of the blades. For all practical purposes, 3 blades is the cannonical sweet spot, so I just went with that. The reason you see so many blades on the old farm windmills is for torque, since these were used to pump water, and that needs a lot of torque to just get started. To generate electricity (something I hoped to achieve), you need some speed, which the farm windmills don’t do so well, due to the drag of all them blades.

Since my windmill isn’t ever going be placed more than 10-20 feet up (I’m living just outside Downtown on a tiny plot of land), I decided that low mass was a requirement: if the spinning part didn’t weigh much, chances are it wouldn’t be able to deliver a head-ectomy if I stumbled into it.

For the original blade “frame”, I’ve elected to use 1/2″ ID PVC electrical conduit for the leading edge and fiberglass rods (originally driveway markers) for the trailing edge. The more flexible trailing edge supports allow for some self-regulation of speed without adding braking mechanisms: as the wind speed increases the trailing edges bend with the wind to reduce the prop speed passively. Since this is a downwind design, there’s no problem with the blades bending enough to contact the mast.

The plastic conduit is rated for above or below ground use, so it will be more resistant to UV aging than white PVC water pipe. It is also flexible, but larger diameter and less flexible than the trailing edges. The larger diameter of the leading edges vs. trailing edges will (I hope) improve the airfoil (once the frame is covered with a tight plastic skin).

Blade Frames

I cut 3-1/2 foot lengths of 1/2inch conduit and drilled a 5/16th inch hole about 1 inch (one hammer head width) in from the outside end. The trailing edges uses the cheap fiberglass rods ( found next to mailboxes at the local hardware store) that measure almost 4 feet long x about 5/16″ in diameter.

With the 1/2″ conduit and the fiberglass rods mounted in the hub, carefully bow the fiberglass rod and stick into the 5/16th hole in the 1/2 inch conduit. This will give you a nice curved frame for the blades with a low angle of attack (pitch).

Blade Covers

Once you have all your blade framed bowed, it’s time to cover them. Continuing my cheapness theme, I made my blade covers using black Visquene plastic (LDPE sheeting, I’m guessing 4-6 mil) that I had laying around. Clear would have been cheerier, but I figured the black would add more UV resistance. It is thick, strong and bonds well using a “Eurosealer”, no glue and no tape required. The Eurosealer was picked up at the local drug-store’s “As Seen on TV” aisle a few years back. The gadget was marketed for resealing plastic food bags, but it’s seen more use making hot-air blimps and oddball projects.

The Infamous Eurosealer

Note: there are battery only models out there, but mine also came with an AC adapter. I’m not sure how long a set of batteries would last making long seams like this project requires.

I put the hub/frame assembly flat on the ground, then draped the Visqueen over each blade frame in turn. Folding the plastic over the 1/2″ conduit, I sealed it around the curved trailing edge using the Eurosealer. I Placed a few “tacks” near the narrow ends and around the center, pulling the plastic as tight as I could easily, then went back and did as continuous a line as I could around the curved trailing edge.

Once the blades were covered (took me a half-hour or so), I tightened up the covers by loosening the set-screws on the couplers holding the 1/2″ conduit to the hub and pushed the conduit into the center of hub just a little further. This bowed out the trailing-edge fiberglass rod to hold the covers taut. (Yes, having an extra pair of hands would be helpful at this stage, since the bowed rods can be kinda strong, but this is not required).
Photos of the process are coming just as soon as I get around to repairing the one blade covering that the dog managed to gouge while the thing was sitting on my porch.

Making the Hub (Method 2)

Cutting PVC lengthwise can produce very usable blades as well. I’ve recently come across some 4 and 6 inch diameter pipes salvaged from a construction site (legitimate scrounged), ann will look at a multiple rotor design along the lines of the “Sky Serpent” method (which I find really impressive).

Measuring Performance of Hub/Blades

Before making your alternator it is helpful to have some data about how the spinning-around-thing performs.
You can spend as much as you want to on a wind data logging unit… or you can spend $10-20 on a bike computer that can tell you a lot that you need to know. For instance, your windmill’s revolutions per minute.

I picked up the cheapest bike computer I could find (a Schwinn). It consisted of a largish digital watch looking thing to mount on the handlebars, a cable/magnetic sensor assembly, and a magnet to clamp to a spoke of the wheel. Instead of a bicycle wheel, attach the magnet (or a magnet, anyway) to the hub of the windmill, and attach the sensor to a part of the windmill mount close enough to pick up the passage of the magnet (it should swivel with the hub/blade assembly). Get the bike computer into set-up mode (I think I had to hold down both buttons for three seconds) and get to where you set your wheel circumference. If you set the wheel to be 1.666 meters in diameter, the KPH readout will equate to RPMs if you discount the decimal point ($10-12 test equipment is GOOD).

The Alternator

For this, my first attempt at homebrew power generation, I took a cue from the gang at the Otherpower website and the very informative How-To file and went with a three-phase dual rotor axial flux design. Unable to decide on which wiring scheme is optimal (star vs. delta) I decided to dress all the coil leads out so that I could switch between them while experimenting. The initial wirir=ng was in :star: configuration.

Since my generator is smaller than any I’ve read about (about 4 inches in diameter, (perhaps too small viz the relationship between disk diameter, RPMs, angular velocity and power output) with only six coils and nine sets of magnets mounted to the rotor disks (a very minimalist design, setting me back $10 in 3/4 x 1/8inch circular rare-earth magnets from the hobby store), results would be uncertain. This is especially true since I made the rotor disks first, and then started doing the math on the coils sizes required, so, anyway, here’s the warts and all situation report:

I’d salvaged two steel disks from the recycle barrel at work (call them 3.9 inch disks). These were used to make the the rotor (magnet-bearing) disks.

I gave them a good de-greasing and washing (and a mild pickling with dilute muriatic acid), smoothed the burrs, and drilled holes in their center points, then marked them up like a clock-faces, with radial marks (center to edge) at 30 degree increments.

I positioned nine 3/4″x1/8″ Neo magnets (from the craft store) about 1/4″ in (one butane lighter’s width) from the edge on each of the two steel disks, let some super-glue ‘wick’ under them, then made a masking tape wall around the edge of the disks, just deep enough to cover the faces of the magnets. I filled the depth of this wall (to the rim) with polyester resin. This encapsulated the magnets, for better or for worse.
That much worked fine.

Arranging the coils inside a coffee-can lid mold didn’t go as well; I think it was the process of placing the weighted lid over the top that disturbed their alignment that threw the coils off-center. Note that the pink stuff around the bolt in the center of the (left) stator disk in a latex masking agent used to keep the plastic coatings from fouling the threads. You can just make out the dental floss I used to tie the coils together in the stator disk before embedding them in polyester resin.

The disk on the left is one rotor, with magnets embedded in polyester resin. Another identical disk is under the stator disk on the right. All those green enameled wired coming from the right-hand disk are from the coils of the stator (connected in “star” configuration, another diagram coming soon).

The scarring on the top rotor disk (left) are from magnetic fragments attracted to the magnets (the silver circles embedded in polyester resin). The stator disk (with the coils) sports a fresh coat of urethane conformal coating followed by a thin coating of silicone conformal coating, to protect the coil wires that had been abraded in early testing. I also increased the air-gap about another .060 inch with an extra washer.

At 1000 RPMs I saw about 12 volts peak-to-peak per phase, which should result in 15 volts or so after rectification with Schottky diode bridges and an output cap on each bridge section. Not bad for a 4 inch diameter brushless alternator weighing less than five pounds built with craft-store magnets. I used no bearings in this early design, as it was a prototype, soon to be reconfigured for extended used.

Since I work with BFMs (big freaking magnets) 8-5 weekdays, I was lucky enough to have a gauss meter/teslometer at my disposal, whereas most home ‘mill builders don’t. If I read the crazy dingus right, with my rotor disks about 1/4 inch apart I was reading 3-4 thousand Gauss. So, that’s the number I’ve plugged into a spreadsheet (of unknown lineage), for calculating the number of coils to use in a given alternator configuration (as well as this one, which could be of use to those ‘rolling your own’). I am assuming these to be simplistic and rough approximations… but they give a starting point, use at your own risk (and I’m new at Google docs, gimme a clue if you got one to share).

[UPDATE 2 FEB2009:  I've been updating my spreadsheet lately.  Bear in mind that the strength of the magnets are of paramount importance, followed by the air gap, then thickness of magnets is my perceived order of precedence in making an effective alternator.  Get the strongest magnets you can, the thinnest coils you can (like single-layer) and spin them as fast as you can.... all else is commentary, except to say if you can't get a full T (Tesla) in the middle of your air-gap (where your coil is) you will have a wimpy thang instead of an alternator, okay?].

16Nov08 Note: the spreadsheet has evolved (not posted yet) but I’ve added an S-rotor calc page, and linked a lot of the variables together from different pages to make it easier to optimize a design for wire AWG, magnet configuration and strength, RPM/windspeed relationships (theoretically tied in with tip-speed ratios and rotor coefficients). It isn’t ready for publication yet, but it should be soon, and I hope it is some help to others in the homebrew community. Chasing all these variables around on separate sheets was like chasing rabbits and starting to make my brain hurt…).

Rethinking the Alternator

Update 16Nov08: Well, the little alternator isn’t performing as well as it needs to for my arcane purposes. I’m only getting 10 volts from it at 1000 RPM, far under expectations. Along with doing some powerful cypherin’ for a new stator/rotor combination (remember that PCB coil thing I was yakking about in another post?), I’m going to remove the excess thickness of plastic ‘potting’ over the rotors and try to tighten up the air-gap, at least until I test to destruction (and can then get on with doing it the right way the second time).

My .75x.125 inch craft-store magnets appeared (after calculation) to be at least N42 NeoFeB disks, which ain’t so bad, but the flux goes to crap at much over .1 inch separation, and I guessing that getting them just a tiny bit closer together could see useful output.

Just noticed that K&J Magnetics has a special on their DX06, a nice little N42, 1 inch round by .375 thick. I’m trying to order a 50-pack for a project at work, and see how they’ll do (Bog willing and the PO goes through).

Some “Real World” Blade/Hub Testing

In my latest test attempt to gather RPM and output data to my windmill (more photos, prose coming on this), I managed to hoist the knock-down bladed windmill up on the 10-foot 1.25 inch length of conduit, only to have the windmill head fall off and land on my foot. Yea, verily and for sooth it did hurt savagely, falling as it did with the rigid conduit straight down. (Note to self, find a way to use a light weight aluminum bade-hub in future designs).

“Oh, fudge” I said. This little piggy got an ice-pack.

Understandably, I’ve backed off just a bit since then, sorry… but more information is coming, as soon as I beef up the mounting method used for the blade/hub assembly (I got in a hurry last time, and it hurt lots).

19Nov08 Update: Have laid in some new materials to correct prior shortcomings in the hub mounting. More pics and prose as they develop.

Some “Real World” S-Rotor Testing

It has to be said, I have a one story house, between a pair of two-story houses (with big trees all around); the worst case scenario for wind-power testing close to ground level. The “good” news is that tonight there are severe thunderstorms moving through the area, with enough wind to really spin the two 5-gallon bucket S-rotor at the top of a 10-foot section of metal conduit I’ve got ‘posted’ in the back yard. I’ve go the bike-computer strapped to it, and will be publishing wind-speed and RPM data as soon as possible tomorrow.

The bottom plywood disk has an 11 inch zinc pulley screwed to it around the central 1/2 inch shaft, and I’ve obtained some angle-iron to mount an axial-flux generator (currently being scaled up) to this with a pulley ration of 11:1 3/4. For the belt I’ll be using the tubular neoprene seals from the bucket lids (it’s only garbage if you don’t use it).

Update 06Nov08: The little Savonius that I built using two split 5-gallon buckets (“Homer” buckets, from Home Depot [cough-sponsorship-cough]), and some 2-foot diameter plywood disks survived the “severe” weather last night. The whole assembly was mounted on a 10 foot vertical metal conduit on a flange bearing, with data collected by the Schwinn bicycle computer. With the lightning flashing last night, I was up on the pole trying to secure a magnet and pickup for data collection, St. Ben (Franklin) was telling me, “Dude, I got fried like this once. Get DOWN!”, but I hung with it. Here’s the data I got:

1. Max RPM:247
2. Average RPM:47

WeatherUnderground shows gusts up to 32MPH for that 24-hour period (I currently lack on-site wind-speed instrumentation. Plugging that data in to my calculations shows that one of two things happened:

1. Either it gusted much higher than 32MPH, or
2. My TSR is greater than 1.2, which is highly doubtful

My current working hypothesis is that I let St. Ben get me panicked, and I forgot to clear memory, leaving previously collected data stored in the bike computer to screw up my results.

Even so, dropping the two-bucket stack (twice) from 10 feet didn’t seem to phase it, so , inefficient or not, the Savonius is a rugged design. That all aside, the rotor did throw the speed sensing magnet sometime during the night. I’m applying more permanent mounting for the magnet (better than electrical tape, anyway, St. Ben was really trying to rush me at the time).

Update 16Nov08: After rearranging the magnet-sensor (and remembering to clear the memory) I re-hung the S-rotor for 23/75 hours starting 2PM 15Nov08. Today the bike computer showed:

• Max RPM: 120
• Average RPM: 40
• 3.75 hours of travel (over 3KPH)

Weather Underground showed a gust of 33 MPH just as I was getting set up, so I’ll call that the 120 RPM maximum figure. These sound like more reasonable numbers for a TSR equivalent of between 0.5 and 0.6 (and 3.75 hours * 4.0 KPH = 15 KM correlates well with the odometer readings), so I’m calling the numbers at least not totally bogus.

19Nov08 Update: Figures from a 3-day trial are in line with last reading:

• Max RPMs: 120
• Average RPMs: 37

If not totally bogus, at least the figures are consistent with my preconceptions. Hopefully upgraded instrumentation will verify these figures.

21Nov08 Update: After a day of strong northerly winds with gusts to 34 MPH:

• Max RPMs: 222
• Avg RPM: 57

Have corrected the dimensions used in calculations. 1.6 ft wide, 1.84 feet high, 2 ft end-disks (1/2 inch plywood). Looks very close to a TSR of 00.52!

08Dec08 Update: It’s been a good and windy couple of days!

• Max RPM: 242
• Avg RPM: 49

(Sorry for the slow progress, pressure of business is keeping me in over-time mode).

Experimental Contagion

The bug is catching… my comrade that runs the water-jet machine is starting to work on his own design, so there should be some interesting synergy. He’s getting interested in the Lenz-type turbine as well. I’m still sticking with the S-rotor (just because of the low level of machining involved and building with mostly scrap materials/found item art aspect).

Continuing…

Currently side-tracked with axial-flux generator stuff.

In answer to the musical question as to “Can a flat coil on PCB work for a wind/water powered project?”, the interim answer is a resounding “Yes!!!”.

As to whether this is the best use of engineering person-loading… well, I’ll get back to you on that.

Check out Otherpower.com for more information on this interesting alternator scheme.