I need a quadcopter icon

I finished putting lights on the quadcopter. Image album!

This involved making little feet to raise the whole thing up 30 mm, and making a little power supply board for them (since they want 12 volts and the batteries might provide anywhere from 11 to 14, depending on battery size). It means I can fly the copter at night, because I can see it. Cassie thinks it looks like a UFO and she's totally right. I'll have to get her to take a video of it next time.

The little yard-space in front of my apartment is big enough to hover in, although not as roomy as the field behind my office. I plan to fly there plenty. :)

Next step is making the lights controllable with a switch on the radio. I'm pretty sure I know how to do that, although the last time I thought that, on Sunday, I started a small fire.

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Today I:

Today I:

- Went to EPO and spent about seventy bucks. I needed some parts for something I'm doing to the quadcopter, putting lights on it. Got 12V voltage regulators (Radio Shack supposedly sells them but they were out), LEDs (I actually already had these but I found better ones), perfboard, wires (better wires for this purpose than what I already had), stuff to make connectors, and some random odds and ends. I forgot to get a switch, which is a little annoying.

The goal here is to have red lights on the back arms of the copter and white lights on the front arms. This way I can see how it's facing in the dark, so I can fly it later in the evening, so I can fly it more often. One of the sort of annoying things about flying something like this is that it's easy to lose track of how it's oriented, since it's square and spends most of its time hovering in place.

- Cleaned my room. Cleaned off my desk, cleaned the work table, put things in boxes and in the closet. I hadn't done this since, oh, October sometime? And in that time I've built several small projects, one big project, added a tool (the cutter), spent two weeks sick, et cetera. My desk was actually buried. Like, the level of crap covered up the bottom of the monitor.

- Put the Commando 23 set on a keyboard. This was a group buy for some keycaps that I got in on a while back, and last week they were delivered. They were the final straw for junk piled on my desk. They look pretty all right on a keyboard though.

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Getting projects done

I've had a piece of cardstock stuck to the cutting mat, ready to be fed through the cutter, for over a month. Tonight I finally got around to doing that, and now I have a little custom deck of Werewolf cards. They're not too fancy but they're definitely a proof that I can make cards. I'll post pictures tomorrow.

Part of the problem is that I am about at maximum table capacity: I had to run a USB cable across the room to reach the cutter, and I'll have to move the whole thing when I want to solder anything again. I can't wait to get into a house and have a room I can line with 6-foot tables.

Cards came out pretty well though. I need to do two things: one, figure out how to do the classic WarGames-like monoline font thing (looks like this). Since it's a cutter, it thinks it's cutting the outline of something, it can't shade in solid shapes. I need to teach it to be a plotter.

Two, I want a better way to remove the cards from the mat than "peel them off individually with a spatula." It's kind of annoying, especially if I want to make multiple cardsheets.

I also got a servo working on an Arduino, and got my print on with a little mount for a laser module. I can now send commands to aim a laser (although only on one axis; I haven't finished the whole assembly yet).

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Flying a quadcopter

My transmitter module came on Friday, so today I went to the field behind my office to fly. Mike, my friend who ran the class for building them, came too.

Hovering inside is more or less easy. Holding a constant altitude is tough, the throttle is really sensitive, making it pretty much like every other RC helicopter I've ever flown.

Flying outside is a bit harder. I don't have to care as much how high I am, so it's easier in that respect, but then there's wind. Holding it steady in the wind (even a fairly light breeze) isn't easy. I did figure out how to recover from an imminent crash: cut the throttle, so I start falling, then gun it right before I hit the ground to soften the landing. I saved the thing from being carried away by the wind a few times by doing that.

We found out that there's an RC hobby place about 15 minutes from work, and although they don't have replacement rotors, they do have tools, servos, radio stuff, batteries, et cetera. I bought some tiny screws and a hot air gun (for something else I'm building).

I also found that some (expensive, carbon fiber) propellers can be had from Amazon for about $16. This is more expensive than the $4 / set prop sets from the Chinese site Hobbyking, but they also don't take three weeks to be shipped.

Why do I care about props all of a sudden? Because, naturally, I managed to flip it over (I blame the wind) and break a prop in half. So, it'll be Wednesday before I can fly it again.

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Building a quadcopter

A few months ago, Tina told me that Mike was running a class at the hackerspace on building remote-control quadcopters, so I signed up. The class was last weekend.

The class cost $250 or so, which included a bunch of quadcopter parts. It didn't include all the parts, though, because some stuff (a radio, batteries and a charger, etc) would already be owned by someone who was into RC stuff, so I had to buy those separately, another $200 or so. Which wasn't really a problem.

First day, I come in a little late, and we start assembling things. I brought my own soldering iron and some other tools, because I was kinda worried that the hackerspace would have crummy tools, and I wasn't disappointed: their iron was pretty low quality and the soldering we had to do was actually fairly hard (really giant wires, to pass really giant currents to motors) so I busted out mine. The guy I was sitting next to, Michael, was really cool and we helped each other out a lot.

First problem I had was that apparently my transmitter module was dead. The receiver works because it worked with Michael's (identical) transmitter, but I can't transmit. Still, I'm able to get everything built by borrowing his transmitter to test it. Solder on some wires, assemble the frame, attach components to the frame, use a laptop to set up the firmware and calibrate the sensors, balance the props, configure the RC controller, it took pretty much all day. But I had the hardware done!

Second day, we get to test them. Everyone took their copter out to a warehouse in the back of the building and we flew them around some. I lagged behind a little bit because I was trying to set up the firmware again on my laptop (I had used Michael's on Saturday) but I eventually get out there, borrow Michael's transmitter again, and fire it up.

The thing flies perfectly. It's completely stable, because the controller board is smart enough to sense whether it's level and adjust it. I can pretty easily hover it at about chest high, move it around, land it without letting it drop too far. Way easier to fly than my other (little bitty) one.

Of course, after flying it for a bit, I discover that the battery charger I ordered was also DOA. Argh.

So, now I have a nice quadcopter sitting on my bed that I can't do anything with. I bought another battery charger from a hobby store locally, and I ordered another transmitter but until I get it in I can't fly it. It's pretty annoying.

On the other hand, after this class, I have a pretty good idea how to build RC things. I think I want to build a little RC robot next, like a tanklike thing (maybe not a tank, maybe wheels, I dunno) with a turret I can aim. I think I can print most of it and I know enough electronics to make it.

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What the world needs now love, sweet love.

Well, no.

If you take an average sea creature and measure the elements it's made of, you find that it (like everything else) is mostly carbon. But there are also some larger elements in trace amounts, that are in a higher concentration in the creature than in the surrounding environment.

The element that is most over-concentrated like this happens to be phosphorus. Phosphorus is the limiting factor of life: given a source of extra phosphorus, life could find everything else it needs to exist in plenty.

So I would say, what the world needs now is phosphorus. That's the only thing there's just too little of.

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Don't want to jinx it

It sort of makes sense: before yesterday I didn't have the energy to post about how I was sick, so right after I did I start feeling better. I don't want to jinx it but you know how there's a sort of intangible switch that gets flipped where you go from "sick" to "tired and hungry but not sick?" That happened last night I think. I was able to eat something, and now I'm still hungry.

I'm also a little stir crazy. I am thinking about maybe going out to a bookstore or something this evening and pretending I have christmas money and spending it. :)

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Happy Isaac Newton's Birthday!

On the 13th or so, I started coughing, a lot. I coughed up white stuff, then yellow stuff, then brown stuff. Then I stopped coughing up stuff, but I didn't feel any better: I still had a fever, I was dizzy and light-headed, and I couldn't eat anything. And I kept feeling like this. I took off the entire week before I was supposed to go on vacation, then stayed in bed the entire time I was on vacation. My fever stopped a few days ago, but I've still been light-headed and crappy. I alternate between lying in bed reading and sitting up watching Parks and Recreation on Netflix.

So I have had a kind of shitty christmas. I spent all day either in bed or on the couch, watching the Doctor Who special and Indiana Jones and the Last Crusade. I ate a couple of ginger snaps and Cassie's leftovers from going to the Cleburne Cafeteria. Finally got Cassie to go on christmas day, and I couldn't ever go with her!

Hopefully I'll start to feel better now. I can do stuff I had planned to do over the past two weeks, like mailing out christmas presents.

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Rescuing Jeb

In my last Kerbal post, I had gotten Jeb (and his assistants, Bill and Bob) to Duna. They landed, they walked around some, they took off again. Then they were out of fuel and hung out in orbit for a couple weeks.

Tonight, I rescued them!

The first attempt was to just get them some fuel. I built a little robotic probe with a big fuel tank and flew it over there. Unfortunately, it took most of the fuel in it to get it there... I'm not good at interplanetary flight yet. So that was a bust. That was about a week ago.

Tonight I tried again though. I built a probe with a larger tank and a nuclear engine. I was able to get it into orbit really easily (I discovered a foolproof way to build launch vehicles), and then flew it over to Duna. I'm getting better, slowly, at interplanetary transfers. The hard part isn't getting to the planet, it's getting to a decent orbit once you're there. You have to spend a huge amount of delta v to get into orbit at all, and unless you make correction burns way before the encounter your orbit is going to be crazy tilted and really high. Like, the first Jeb mission ended up in a polar orbit around Duna.

So, okay, got there. Rendezvoused and docked with the stranded ship. Now for the second part of my plan: the ship that I first sent there had four small landing rockets on it. These are great for landings but they use way too much fuel for interplanetary flight. The nuclear engines are the exact opposite: low thrust but extremely low fuel usage. The same tank that had maybe 2000 m/s delta v gave me over 5000 with a nuclear engine.

Which meant that after I got to Duna, normalized my orbit, rendezvoused, and docked, it made sense to just throw away most of the original ship and carry the crew capsule home with the probe. Which I had about twice the delta v I needed to do. I burned back home, made a correction burn (getting decent at those by now), and got back into Kerbin orbit. I could have made a really fast reentry there, but I figured what the hell, and actually took a couple orbits to slow myself down. I managed to actually stay out of the red zone on the G meter during reentry.

Next task: rescue the guys I left stuck on Duna's moon. That'll be tough because they can't even take off, they're so out of fuel.

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