How come?

How come as soon as you have a new hobby, events conspire to make sure you can't do anything about it? In the last week we've had a hurricane (can't fly kites in a hurricane), a wildfire that almost took out my neighborhood (can't fly kites in smoke with helicopters), a tsunami warning (ok, ok, so you can fly kites during a tsunami... besides, it hit at 3am), and some nasty sessions at work (no flying at lunch.) I just wanted to fly!

So how come when you think you have your best hobby day in a long time, you find out later you're wrong? To be fair I have to temper that statement somewhat. I took off for work early (we're going to be at a remote work site for upwards of eight to eleven days, and I got a head-start). It was howling tradewinds when I left home (upwards of 40kts) but it was just a nice steady breeze at the pu'u I wanted to photograph. Kite went up, it was rock solid in the air, so I hooked up the rig and let out line. Hot dog! The rig was stable, I got lots of photographs (81), and the camera didn't go to sleep even once during the entire hour-long session. I was stoked!

Aaaaand then I took a look at the pictures. I can't say I was disappointed, bu... no, actually, I was pretty darned disappointed. I missed several targets (I still can't aim the thing well) and the rig was right in the sun most of the time, so I was flying blind for the most part. I think I'd have had better luck with an autoKAP rig and a lot more walking.

In any case the wind cooperated, and I'm interested in trying it again later in the week.

On other news, my shop is still a mess, but I've come up with some projects to do. A lot of strictly 2D milling, but if I can get all the parts to fit in a 6"x6" square I can prototype them in 1/16" 6061 and then make the final parts using carbon fiber. But I'll likely have a waterjet house cut the carbon fiber. It's hellish on tools and lungs.

I convinced some folks at work to look into the Atmel ATNGW100 network gateway demo board. It's an AVR32 processor running an honest to goodness installation of Linux. Out of the box it's running Samba, Apache, sshd, and a bunch of other stuff. We're looking at it for the automation project that's going on, but I'm also interested in it for a few other reasons as well:

Your typical Linux server (not desktop) draws roughly 100-200 watts constantly. Say you've got a server that serves web, mail, disk, and a handful of other services in addition to ssh for logins. 100 watts, 24 hours in a day, that's 2.4kWh to run the thing.

Now just suppose you used an ATNGW100 to do the same thing. It consumes around 100mW, though it has no disks. It can act as a USB host, though, so USB or network attached storage can provide disk. (It does have an SD and MMC card slot, but constantly banging an SD or MMC card will kill it in short order.) If you can manage to arrange your fetchmail cron jobs so it only turns on the disk once every ten minutes or so, you're still looking at roughly 150mW. 24 hours in a day, that's 0.0036kWh per day. That's a lot better.

Mind you I haven't tested this, but it's a plan in the works. I should have the ATNGW100 in about a week, and should be able to try setting up a replacement Linux host shortly after that. Radio Shack sells an IDE->USB enclosure that'll take any IDE drive. (But for a little more I can get a 250GB USB drive, so I'll probably ask my boss to spring for that instead.) Hope it works.

By extension, these could also be extremely cheap DNS, DHCP, NIS, etc. servers. One of the best DNS/DHCP implementations I saw was this very scalable, highly redundant multi-server setup a friend of mine did for Tivoli. If this could be done on a slightly smaller scale using ATNGW100 boards, but losing none of the redundancy and fail-over functionality, that could be a really nice alternative to the single point of failure model so many small business use.

A quick rant: At home I run a single Linux server that takes care of several tasks. But I would never ever do this in the work place. It's asking for trouble. Get separate machines for each service: one for mail, one for DHCP/DNS, one for web, etc. Preferably get more than one so you have some fail-over assurance. But at no point should a single point of failure for one service mean that another service might be compromised. I've been at places that use the home model at work, and it never performs well.

This is one of the reasons I'm so interested in seeing if the ATNGW100 can be used this way. Figure your typical new Linux machine is between $500 and $2500 US. An ATNGW100 is $89. Add a nice case and a wall wart power supply and the price is about $120. You can get four of those for the price of a desktop "server" or upwards of 20+ for the price of a decent server. Set some up as load-balancers and the rest up as redundant single-service servers, and you have an infrastructure that would be very very hard to take down, and dead-easy to maintain and upgrade with nearly zero down-time.

Can't wait to find out if I've got my foot shoved in my mouth for saying that! Only time will tell.

Tom

Ups and Downs

It was the best of times, it was the... well... no, actually times have been pretty good.

Sports mode on my camera is lame (it goes to "sleep" (as opposed to "powered off") after five minutes, despite the auto power-off setting of 30 minutes), the servo change gets me a full 90-degrees of tilt (good!) the new kites rock the house, and I got several hours of flight time over the weekend and this week.


I got my first real honest-to-goodness planned shot (a vertical portrait) and my first kite-photographing-another-kite shot (I had two line tangles before all was said and done, but I got one decent picture). I completely drained the batteries on my transmitter, found out the new charger automagically powers off when the battery is charged, and feel a lot more confident in the setup now.

I've got plans to make either a 6' or an 8' rokkaku to compliment the Flowforms, and should be expanding my available wind range by a lot in the very near future. Life's good.

Then I unwittingly stepped into the proverbial "it" in a discussion forum, making some off-hand comments in a thread on rig stability that was a lot more heated than I thought. I hate it when that happens. I hope my comments didn't do anything to throw fuel on a fire, but chances are they did. In any case I'm new to KAP, I really don't have any usable input to share, so I'm dropping out of that discussion.

Which leaves more time for flying, so I'm taking that as an up and smiling, regardless.

In the meanwhile I spent some time this morning cleaning out the shop. I don't have any plans at the moment to make new stuff, but it's getting close. A fellow KAPer from Brazil posted some videos of his CNC router doing gear-cutting on Youtube. That got me to thinking about my whole strategy of proofing robot parts on the scrollsaw. I think maybe I should come up with a sacrificial router table I can bolt to the mill and use it to make bot parts instead. Take off the rotary axis, take off the vise, and just leave it in 2D mode for a while. It might see more use that way.

Something else is coming up at work that might involve thread milling. That's something I've been itching to do for some time, so I'm looking forward to it. This technique can also be used to make things like filter rings for cameras, so there's plenty of cross-over potential.

Ups and downs, but on the whole life is good. Plus, the wind is up, the sun is shining, and my kite bag is in the car. I'm flying at lunch time. Can't beat it.

Tom

Airborne At Last

My kites should've arrived Saturday, but there was no notice at the post office. I checked on Monday, but no notice. So Monday night I used the USPS tracking page and... Yep, it had been delivered Saturday morning at 6am, but I never got my yellow card to tell me it was there. So Tuesday morning I asked if I had a box, and sure enough there it was. NEW KITES!

By the time I got back to my car, the rain had started... The fates love me.

So I spent some time installing the PeKaBe blocks (which are great) re-rigging the tails to fit onto the Flowforms (which was dead-easy) and finding some way to put a thousand feet of #250 dacron line onto a winder (I used an extension cord reel from the hardware store). Yep, still raining.

It rained the next day, too. So I drove home at the end of the day and... no rain! No rain?! No rain. I grabbed the kite bag, grabbed some kids, and almost sprinted to the pasture near my house only to find... It was full of cows who'd probably bolt at the sight of a great big flying mattress, and probably poop on my gear. So I threw kids in the car, threw my kites in the back and took off. I drove until sun-down, and one after another I had no-go flying sites (no wind; wind, but helicopters; no wind; wind blowing into power lines; wind shift, and the power lines moved to the other side, so back into power lines; rain). The fates love me.

So finally it was clear this morning. I had some time before an appointment, so I launched. The new kites are outstanding. The wind was gusty, so I can't say they were rock solid (no kite would be in gusty wind) but it was pull and lull in turns, not wild gyrations all over the sky like the older kites! I threw caution to the wind (har) and hooked up my rig. A quick gear check and I was airborne again! Click click click... click click... click... Five minutes before my appointment I walked the kite down, put the gear away, and took off. It was a good two hours before I got to look at what I'd captured on camera. I loaded the card, opened it up, and... Quicktimes? Somehow my camera had been set to movie mode. ARGH! The fates love me.

I went back out at lunch (of course) and made sure the camera was set to photo mode. All in all things worked out well. There was maybe one keeper out of about thirty images, but I learned a lot from my mistakes. I have some wind-induced tilt to the rig I need to think about. I found a sports mode setting on the camera that gives significantly faster shutter speed, making for fewer blurred shots. I found out that KAP movies make me nauseous. Even when I did them on purpose the second time. Too much motion.

All in all, though, I'm stoked. I have some stuff to try out (sports mode, check rig balance, try to get more travel out of my tilt servo), I have an utterly unphotogenic site to test at, and I have a weekend full of beautiful beaches to look forward to with my hopefully newly developed technique.

Maybe the fates really do love me after all!

Tom

Back in the Shop

Since it's the shop that let me buy my kites, it's the shop I'm turning back to now while the kites are still in the mail. I've sorted through my ongoing project list, and picked two of them to really hammer on:

The first is a spindle tachometer. The need's easy to demonstrate. This question shows up on the online forums all the time: how to tell how fast my spindle is going? There are a number of approaches to sensing, but what's needed at the other end is a numeric display of some sort. This implies either LEDs or an LCD. For readability, the bigger the better (within reason!)

So I took a look at the AVR Butterfly, which has a pretty big segmented LCD. Six characters, so it'd be good to several tens of thousands of RPMs. And the Butterfly has an ATmega169 onboard running at 8MHz (with the right fuse settings) so it's got plenty of horsepower. Only problem is all the I/O pins that can act as clock sources for the onboard counters are all tied up with the LCD. ARGH! And INT0 and INT1 pins are tied up, too. Which leaves the normal pin change interrupt routines, which are slower. But at 8MHz the 169 can easily keep up with a spindle rotating at up to 30kRPM.

Rather it could keep up with a spindle sending out 30k pulses per minute, which is different. For sensing I'm going to document three approaches: One uses an optical interrupter to read holes in a plate. My mill has a single index hole, my lathe has a 60-hole indexing plate for doing live tooling index jobs. So the number of pulses/rev would have to be user-settable. The second method is to use an optical reflector reading black and white stripes off a pattern that's copied or laser printed and affixed to the end of the spindle pulley. The third is to drill and embed a neodymium magnet into the pulley and read it with a Hall-effect switch. (Surely among these three the interested reader could find one they'd feel comfortable with! The article would then give instructions for downloading the Butterfly's source off of AVRfreaks or Sourceforge.


The second article would be a much longer and much more thought out version of my toolbar article for the mill-as-lathe. The difference is I'd also go ahead and include all the stuff for using the mill as a lathe, multiple tools, switching coordinate systems to pick up offsets, etc. This would hopefully be useful to someone with a CNC mill but not a CNC lathe (like me!) and also force me to start using multiple tool settings. In the process of writing the article I know I'll stumble a lot, so with any luck the final article will point out some of the more likely pitfalls and try to save the reader from running into them full-tilt (like I'm sure to do.)

This means I'll have to finish my second toolbar, drill the cross-holes so either one could be mounted vertically or horizontally, and add the holes in the second bar to take drill bits (or make bolt-on units in place of the tool caps.) In the end I'll have what'll probably wind up being a multi-issue article (my first!) and a full-blown twelve-tool plus six drill position toolchanger for my CNC face lathe.

I just hope it doesn't take three years to get this stuff published this time... Need more kites...

Tom

Chewing Fingernails and Shifting Gears

Ok, so when I posted last I'd picked out the kites of choice, but hadn't been able to order. Now I've ordered, but won't have the kites for several days. Gnargh! Gotta stop chewing my fingernails and relax, I suppose. If it was only that easy...

After measuring the two kites I do have (both parafoils, both unstable in the air) I have a 2.0 and a 14.5 sq ft kite. The line I thought was #200 wasn't, so I picked up a thousand feet of #250 black dacron line and a new hoop winder. (I repaired my old hoop for the third time, and plan to put my old line back on it. It's good line! And now I've learned if I fall, not to land on the winder.)

The check for the article really was $240, so that left me with a little extra. Almost $40, to be exact. Which is just the price for four PeKaBe blocks. Yahoo!! I've been eyeballing PeKaBe blocks for my RC sailboat for years, and have been eyeballing them for KAP since I first started trying to design a real KAP rig. Every comment I've seen people write about the PeKaBe blocks has been positive. And since it's something that tends to be a buy once, I'm hoping it's $40 well-spent. The only real concern is something from http://arch.ced.berkeley.edu/kap/kaptoc.html regarding balance. The PeKaBe blocks are so friction-free, any imbalance in the rig really really shows up. So I'll probably be due for a re-balance, and it'll be time to finally strap on the permanent battery and retire the AA battery pack.

Taking some more advice from the KAP forum, I'm going to spend at least a couple of outings just learning to fly the Flowforms. The next step will be to hook up a 713g dummy weight 100' down-line from the kite, and fly it as if I have my KAP rig on there. Once I'm comfortable with the kites, and know their limits in the winds we get around here, then I'll hook up the KAP rig and get airborne again.

So I'm still chewing my fingernails, but at least I've changed gears. I started off chewing my fingernails because I couldn't get my kites to reliably lift my rig. Then I was chewing my fingernails because I knew what the fix was, but couldn't afford the new kites. Now I'm chewing my fingernails because I know the fix is sooooooo close, but not here yet. But at least now I know it's in sight. It'll happen. And I will eventually get airborne and be able to keep it that way.

Aaaaahhh...

Ok, time to write the next set of articles. This last one saved my butt!

Tom

KAP is Another One of Those Hobbies

My wife and I have expensive hobbies. I'm a home shop machinist. She's a jeweler. We both do photography. We both like to fly kites. And now I'm combining the latter two with KAP.

"No problem!" I thought. "I have kites, I have a camera, I have a radio, it's gonna be easy!"

Hahahahaha! Oh how naive I have been. As life turns out, the kite I've never been able to get to fly well still doesn't fly well. Last Saturday the kite pulled a 180, screamed for the ground, and wound up in a kiawe tree (think of a mesquite tree, lengthen the thorns, and you're there). Recovered, flew again, things got stable, put on the rig, flew it to about 50', then the kite dove for the ground again. KAP rig in the kiawe this time, the kite out on the lava. Recovered, packed up, and moved to another beach. Stable as a rock. GREAT! Nope, the kite pulled a 180, the KAP rig hit rocks, the kite hit asphalt, the line was draped over all kinds of scrub.

So I fielded some questions on the KAP forums. The consensus was that parafoils are notoriously hard to tune, finicky, and yeah, what I'm seeing indicates an out of tune kite. Rather than frustrate myself and lose my rig with the thing, I started looking at replacements. Lots of good advice there, too. I'm planning on getting two Sutton Flowform kites. One's an 8 square foot kite (to replace my smaller parafoil with a slightly larger sail - great for Waimea). The other is a 16 square foot kite (to replace my 14.5 square foot parafoil... the one that's giving me fits.) Throw in a thousand feet of #250 line for the FF16, a 9" hoop winder for the new line, and my price is up to $200 US.

Sigh... And here I thought I'd finally found an inexpensive hobby I enjoy. NOPE!

Good thing is I just got notice that an article I'd written three years ago actually got published. I ran through the article as printed, compared it to the payment schedule from three years ago, and figure it should be around $240 for the article. Egads I love how life turns out sometimes. I hope to get the check in the next few days, and will order all the new kite gear the same day. 'Till then I'm grounded.

But being a tinkerer and being unable to let something go just because it's "broken", I'm still planning to tune that parafoil. I may never hang a camera from it again (in fact I mean not to). But if I can get it tuned, it'll be one more skill I know I can pick up, and I'll have a kite I can dedicate to flying with the kids.

Tom

My Third Eye Really Is Blind

I used to do a lot of photography. 35mm and 4x5 were my media of choice. Then came kids. And I hate to say it, but the cameras really took a back-burner. Sure, I learned to use a point & shoot, and learned to do snapshots. In the process I learned that doing hard-core portraiture on a rapidly moving, often gooey target really wasn't all that fulfilling. So the cameras sat idle, my photographic synapses sat idle, and time passed.

About two years ago my wife and I sold all our 35mm camera bodies and film point & shoots, and used the money to buy a digital SLR body. Since we already had Canon EOS lenses, we went for a Canon D20 digital body. Fantastic camera. I love it. I just wish I got to use it more. Granted, I'm using it far more than I did the 35mm gear in the Post-Child era, but it's still nowhere near what it used to be when we were going out on the weekends simply to shoot.

I went through some pictures I've taken with the D20, and while technically the keepers really are keepers (sharp, no motion blur, good exposure levels, etc.) artistically they're a wash. If I look at some of my earlier work I can take in a shot and think, "Isolation", "Growth", "Perseverence" (and toss in every other catchword you've seen on a motivational poster.) Looking through my recent stuff I'm seeing "plant with rocks", "beach", "forest".

What it boils down to is this: I wouldn't hang any of it on my wall. We do have some of our own photography hanging on the walls at home. We've also got some Ansel Adams, Redeka, and Brandenburg, just to keep stuff in perspective. But I'm still happy to hang the shots of ours that we did. I'll never have Ansel Adams's artistry, but I can sure try.

I think it's still a problem of time. By way of example, I love doing 4x5 photography. You have one film holder with two sheets of film in it. The image on the ground-glass is upside-down and backward. Composition isn't so much placing objects in the frame, it's placing shapes and colors on a canvas. And I could easily spend an hour or more composing a single shot. Since I typically shoot B&W when I'm doing 4x5 (only one of my lenses is corrected in more than one color), I'll then spend another hour dinking around with filter choice. Then I'll decide the light's not right and make notes so I can come back to that spot some other day when the light is better. It's a glacially slow process that in the long-run can be very very rewarding. But to an innocent bystander? It's the Hell of Watching Paint Dry.

Needless to say, in this, the Era of Children, I don't often get the chance to spend hours on end staring at a ground glass with a towel over my head. I also don't often have the chance to work that way with the Canon gear, either. Photo sessions are a lot more rushed, and rather than being able to take the time to work with the camera until I really get what I want, I'm having to make do with what I can get. It shows.

My photographic eye is blind. I've lost track of what really makes a good shot. But I'm determined to get it back. I know I only developed it the first time by really working hard, shooting truckloads of film, and studying what I like in other photographers' work. So it'll be a long, long process. But it's worth it to me.

Tom