So I've been drooling over Raspberry Pi for ages now, and finally got one. Now I'm staring at it like it's a giant blank canvas. What should I use it for? The possibilities seem endless!
My thinking is that I have very high ambitions for Halloween this year, and I could really use a CNC router table capable of chopping up full sheets of plywood. I've always wanted to work on robots, and this seems like the perfect project to learn about it. So... that's what I'm going to do.
I understand the concepts of CNC router tables: given a set of coordinates, one can use stepper motors to spin some threaded rod, which will push nuts which are connected to a gantry, thereby moving it back and forth. Alternatively, one could use a belt drive. In any event, a computer controls the motors and keeps track of where the router is. It raises and lowers the router, thereby controlling depth of cut, and moves the router in x and y, thereby cutting shapes.
So the questions I have are:
1) How easy (and cheap) is it to drive stepper motors using raspberry pi.
2) Can said motors spin large enough threaded rod to push a 4 ft long gantry a distance of 8 ft, and to push a router along the gantry?
3) Can I find 8 foot long sections of threaded rod in order to build a CNC router table that will cut a full sheet of plywood?
Only one way to find out!
Thursday, April 4, 2013
Wednesday, April 3, 2013
Mississippi crawls toward freedom: loosens restrictions on carrying a gun
I am a fairly libertarian guy. There aren't many questions of governmental matters where I would call for more government. In fact, as I write this, I'm trying to come up with a list, and I'm drawing a complete blank. I'm not sure if that's because there aren't any or because I'm half asleep.
In any event, a few days ago, I came across this map on Facebook. I think it was Judge Andrew Napolitano who first posted it. Basically, the map is color coded to show freedom among the 50 states. Cooler colors indicate less freedom. Mississippi ranks #41. That's pretty damned depressing, given that I live in Mississippi and honestly believe in freedom. But hey, at least I'm not living in California or New York, eh?
Unfortunately, the site doesn't give a line-item breakdown of their analysis. They give a pretty detailed list of how the rankings are calculated, but don't list how the various states score on each line-item. I largely agree with their definitions of freedom as well, as they all seem to center around the same theme I would choose: getting the government out of the lives of the citizenry.
So why does Mississippi rank so poorly? I think a lot of it stems from the strong desire of many inhabitants to have theocracy. I.e., rather than allowing freedom and shaming what they see as sin, they prefer to wield the power of the state and enforce their religious dictates upon the people. Hence a very high incarceration rate for "crimes" like marijuana use, a ban on homosexual marriage, and requiring blood tests and a waiting period for heterosexual marriage.
Are there any silver linings beyond "we don't suck as badly as New York, California, New Jersey, Hawaii, Rhode Island, Illinois, Maryland, Vermont, or West Virginia?" Well, yes. Yes there are. To wit:
In any event, a few days ago, I came across this map on Facebook. I think it was Judge Andrew Napolitano who first posted it. Basically, the map is color coded to show freedom among the 50 states. Cooler colors indicate less freedom. Mississippi ranks #41. That's pretty damned depressing, given that I live in Mississippi and honestly believe in freedom. But hey, at least I'm not living in California or New York, eh?
Unfortunately, the site doesn't give a line-item breakdown of their analysis. They give a pretty detailed list of how the rankings are calculated, but don't list how the various states score on each line-item. I largely agree with their definitions of freedom as well, as they all seem to center around the same theme I would choose: getting the government out of the lives of the citizenry.
So why does Mississippi rank so poorly? I think a lot of it stems from the strong desire of many inhabitants to have theocracy. I.e., rather than allowing freedom and shaming what they see as sin, they prefer to wield the power of the state and enforce their religious dictates upon the people. Hence a very high incarceration rate for "crimes" like marijuana use, a ban on homosexual marriage, and requiring blood tests and a waiting period for heterosexual marriage.
Are there any silver linings beyond "we don't suck as badly as New York, California, New Jersey, Hawaii, Rhode Island, Illinois, Maryland, Vermont, or West Virginia?" Well, yes. Yes there are. To wit:
- In November 2011, Mississippi voters banned the use of eminent domain to transfer ownership of land from one private owner to another. This is huge. The only "legal" use of eminent domain under the new law is for public use. I still have a problem with this, but it's much less offensive than the typical, "hey we're going to take your land to promote gentrification and build a larger tax base." What's more, the ban passed by ballot initiative, with 73% of the vote. Why 27% of the population would vote against that, I will never understand. I guess they don't own any land, or were hoping to confiscate some through the state system.
- On the same day, Missisippi voters rejected the personhood initiative, by a vote of 57% to 43%. Mississippi houses a mostly a pro-life populace, so this is very surprising to me.
- Most recently, the state house turned Republican, and gun laws were some of the first to get some freedom loving. Apparently there was a recent court case where it was judged that although Mississippi allows openly carrying without a permit, holstering a weapon will partially conceal it. In other words, if you wanted to carry your gun without obtaining a permission slip, you would have to literally carry the gun, in your hand. Because that's safer than putting it in a holster. The effect was to completely neuter the law allowing openly carrying. The new law, which becomes effective July 1, 2013, explicitly defines the term "concealed" such that a non-permitted resident can holster a weapon on their belt or shoulder, and as long as that holster is at least partially visible, they're in the clear.
(4) For the purposes of this section, "concealed" means hidden or obscured from common observation and shall not include any weapon listed in subsection (1) of this section, including, but not limited to, a loaded or unloaded pistol carried upon the person in a sheath, belt holster or shoulder holster that is wholly or partially visible, or carried upon the person in a scabbard or case for carrying the weapon that is wholly or partially visible.Hopefully these changes help the state of Mississippi crawl from 41st to 40th and beyond. Decriminalizing sudafed would be a nice start :-)
Tuesday, April 2, 2013
The Worst Injury Ever
This one time around 1995 Ben Gilley, some other guys, and I went to Tupelo, MS, to
skate this park that some guy was running over there.
We'd been there for something like 6 hours and hadn't had any food or drink, so I sat
down to gather my strength for a trip to Taco Bell.
I decided to watch this BMX dude from Memphis who was doing some pretty crazy stuff -
backflips on the short vert wall, 360's over the spine.
He was riding with a broken ankle, to boot!
Anyways, his buddy decided to start video taping the session, and he started really going off. He tried a 360 off the side of the spine, into the flat, and had to take one foot off on landing. So he told his buddy he was gonna give it another try, so it would be clean. He went back, hit the backflip with complete precision, went for the 360, and as he was going off the spine, his front wheel slammed into the side of the spine, right below the coping. Next thing I knew, he was on his back, screaming, and the bike was God-knows-where. It looked like his shoe was hanging off the tip of his toes, because it was all backwards. NOPE - his shoe was tied tight. His whole foot was dangling at his ankle. Totally nasty. So of course, every body in the park just sat down and it got real quiet. The BMX kid actually reached up and tried to put his foot back the way it goes, like it would help. His buddy came running over to him, yelling, "Just let yourself go into shock, dude!"
At this point, I turned to Ben, who was sitting right next to me, and said something like, "Hey, not to be insensitive, but do you wanna make a run for the border?" After a few minutes, we went to Taco Bell and had a bite to eat. When we got back, Ben's leather jacket was missing. After a little investigation, it turned out that the BMX kid's friends had thought it was his and took it with him to the hospital. So Ben and I went to the hospital to find his jacket. We got to talk to the BMX kid a little bit. He said he was completely dosed on morphine, but his ankle still hurt pretty bad. They didn't have it in a cast yet, because they were going to have to do surgery. It was swollen BIG TIME. Then he started telling us how when he was trying to set his foot, he could hear all the bones and what-not crunching around inside his ankle. Awful... And finally, his girlfriend mentioned that the doctors had already done X-Rays and what-not and determined that he had broken everything in his ankle. Bones, ligaments, tendons - everything. Apparently, the only thing holding his foot on was his skin.
And that is the nastiest injury I've ever seen in person.
EDIT: Some 20 years later, and I finally have a name to go with this story. Here's what my friend Kris Gurley had to say:
Anyways, his buddy decided to start video taping the session, and he started really going off. He tried a 360 off the side of the spine, into the flat, and had to take one foot off on landing. So he told his buddy he was gonna give it another try, so it would be clean. He went back, hit the backflip with complete precision, went for the 360, and as he was going off the spine, his front wheel slammed into the side of the spine, right below the coping. Next thing I knew, he was on his back, screaming, and the bike was God-knows-where. It looked like his shoe was hanging off the tip of his toes, because it was all backwards. NOPE - his shoe was tied tight. His whole foot was dangling at his ankle. Totally nasty. So of course, every body in the park just sat down and it got real quiet. The BMX kid actually reached up and tried to put his foot back the way it goes, like it would help. His buddy came running over to him, yelling, "Just let yourself go into shock, dude!"
At this point, I turned to Ben, who was sitting right next to me, and said something like, "Hey, not to be insensitive, but do you wanna make a run for the border?" After a few minutes, we went to Taco Bell and had a bite to eat. When we got back, Ben's leather jacket was missing. After a little investigation, it turned out that the BMX kid's friends had thought it was his and took it with him to the hospital. So Ben and I went to the hospital to find his jacket. We got to talk to the BMX kid a little bit. He said he was completely dosed on morphine, but his ankle still hurt pretty bad. They didn't have it in a cast yet, because they were going to have to do surgery. It was swollen BIG TIME. Then he started telling us how when he was trying to set his foot, he could hear all the bones and what-not crunching around inside his ankle. Awful... And finally, his girlfriend mentioned that the doctors had already done X-Rays and what-not and determined that he had broken everything in his ankle. Bones, ligaments, tendons - everything. Apparently, the only thing holding his foot on was his skin.
And that is the nastiest injury I've ever seen in person.
EDIT: Some 20 years later, and I finally have a name to go with this story. Here's what my friend Kris Gurley had to say:
No that guy was Jason Childers. He had stories at parks all around here. It seemed that every park we went to, he had been there the week before and wrecked himself. "Wait, you guys are from Memphis? There was this biker dude from Memphis here last week and almost killed himself!" We went to that Tupelo park the week following that particular incident. I think it was run by a dude named Matthew Robinson or he had something to do with it if I remember right.
Iocane Powder and Poison Ivy
In our ongoing quest to build a castle, we have hit our first challenge. The land we purchased is riddled with poison ivy. Jeania appears to be way more easily affected by the stuff than I am, having it spread across her body at the slightest exposure to urushiol oil. I've managed to suffer through a rash on my left wrist and right ring finger.
We've tried all the usual remedies: calamine lotion, aloe-based lotions, vinegar, commercial poison-ivy soaps, and for Jeania, a steroid shot followed by a 5 day steroid pill regimen. In general, all of them help to sooth the pain and reduce the severity of outbreaks, but none have put a stop to it.
About a week ago, we started trying a product called Oral Ivy, available at Amazon. So far, we have had no ill effects, and it has helped Jeania's pre-existing rashes to dry up quite rapidly. We do not yet know if its claimed prophylactic effects are real, but we're trying it and I will report on that later.
It is a strange product, to be sure. It is simply poison ivy infused into an alcohol solution. That sounds like the absolute last thing you would want to ingest if you're allergic to poison ivy's urushiol oil. In fact, it sounds downright dangerous. But perhaps there's some logic to it - by providing small enough doses over a long enough period of time, maybe the body reduces its sensitivity or builds up an immunity, like Wesley built up an immunity to Iocane Powder in The Princess Bride. Who knows? Like I say, we're trying it and will report on its efficacy in the coming months.
UPDATE 2013-04-04: Jeania's most recent rash has not itched since Tuesday, and has subsided substantially. So far, this is looking very promising, as Jeania's previous outbreaks have lasted much longer, and urushiol- induced rashes supposedly get worse with each encounter. Still no ill side-effects.
UPDATE 2013-05-13: Well, it's been about a month and a half, and this stuff is amazing. Last Sunday, we were cutting down some trees and I had to move a log right by Jeania's head (long story - I need to write that one up). On the log, there was a hanging vine of poison ivy that I hadn't noticed, and it slid right across her face. She has had no rash from it whatsoever. I cannot recommend Oral Ivy enough.
UPDATE 2013-05-22: Jeania developed a poison ivy rash on her leg. We are not sure if there was direct contact, or if she scratched a mosquito bite and the urushiol oil in her body from the vine-to-the-face incident found a foothold to irritate the skin, or what. She increased her Oral Ivy dosage, and the rash has subsided and is disappearing. The instructions for Oral Ivy indicate that if you already have a rash, you should take several drops, several times a day, and during the rest of the season you should take 5 drops a day prophylactically. We're disappointed that the prophylactic effect has not been 100% perfect, but pleased that the "with-a-rash" regiment continues to work. Hopefully this isn't a sign that the body will lose resistance with prolonged use. Amazon reviews seem to suggest that isn't the case. Fingers crossed.
We've tried all the usual remedies: calamine lotion, aloe-based lotions, vinegar, commercial poison-ivy soaps, and for Jeania, a steroid shot followed by a 5 day steroid pill regimen. In general, all of them help to sooth the pain and reduce the severity of outbreaks, but none have put a stop to it.
About a week ago, we started trying a product called Oral Ivy, available at Amazon. So far, we have had no ill effects, and it has helped Jeania's pre-existing rashes to dry up quite rapidly. We do not yet know if its claimed prophylactic effects are real, but we're trying it and I will report on that later.
It is a strange product, to be sure. It is simply poison ivy infused into an alcohol solution. That sounds like the absolute last thing you would want to ingest if you're allergic to poison ivy's urushiol oil. In fact, it sounds downright dangerous. But perhaps there's some logic to it - by providing small enough doses over a long enough period of time, maybe the body reduces its sensitivity or builds up an immunity, like Wesley built up an immunity to Iocane Powder in The Princess Bride. Who knows? Like I say, we're trying it and will report on its efficacy in the coming months.
UPDATE 2013-04-04: Jeania's most recent rash has not itched since Tuesday, and has subsided substantially. So far, this is looking very promising, as Jeania's previous outbreaks have lasted much longer, and urushiol- induced rashes supposedly get worse with each encounter. Still no ill side-effects.
UPDATE 2013-05-13: Well, it's been about a month and a half, and this stuff is amazing. Last Sunday, we were cutting down some trees and I had to move a log right by Jeania's head (long story - I need to write that one up). On the log, there was a hanging vine of poison ivy that I hadn't noticed, and it slid right across her face. She has had no rash from it whatsoever. I cannot recommend Oral Ivy enough.
UPDATE 2013-05-22: Jeania developed a poison ivy rash on her leg. We are not sure if there was direct contact, or if she scratched a mosquito bite and the urushiol oil in her body from the vine-to-the-face incident found a foothold to irritate the skin, or what. She increased her Oral Ivy dosage, and the rash has subsided and is disappearing. The instructions for Oral Ivy indicate that if you already have a rash, you should take several drops, several times a day, and during the rest of the season you should take 5 drops a day prophylactically. We're disappointed that the prophylactic effect has not been 100% perfect, but pleased that the "with-a-rash" regiment continues to work. Hopefully this isn't a sign that the body will lose resistance with prolonged use. Amazon reviews seem to suggest that isn't the case. Fingers crossed.
Monday, April 1, 2013
Castle, part 1.
I've decided to take on the very-long-term project of building a castle. For those who don't know, I've purchased 12 acres of land, with the express goal of eliminating debt from my life and minimizing my cost of living. That means that I need to divest myself of my current house and replace it with a paid-for house, though not necessarily in that order :-).
When I say "build a castle," I really mean "stick-build a house which looks an awful lot like a castle." I intend to do most of the construction myself, partly to reduce the cost, and partly because I enjoy construction.
There are some interesting features of the land I purchased which make this endeavor something that is not entirely unreasonable:
Oak and cypress are materials which are fairly expensive. At the Home Depot, a 1/2"x2"x4' board of red oak is $4.12 right now. That's 1/3 board feet, so $12.36 per board-foot. An 8 ft 2x4, on the other hand, is 3-1/2 board-feet, and costs $3.12, so $0.89 per board foot. That's a 13.86:1 ratio. A 32-foot long, 8" diameter log is 9650 cubic inches (32*12*8*π), or 67 board feet. That's about $800.00, or 265 pine 2x4's (!!). At 16" centers, those 2x4s would cover 353 feet of distance (not including sill plate or top plate.) That's enough to frame all of the exterior walls on one floor of my current plan. Having a source of oak is clearly a Good Thing™.
The creeks. Ahhh, the sweet sweet running water. That's pure gold, right there. First, and most importantly, local laws allow me to dam them up, thereby turning them from creeks into a moat. I'll have to cut a bit on one side of the property to make the moat completely surround the castle, but I'll still have an honest-to-goodness moat. By having a dam, I can direct the flow through a turbine and get electricity. I don't think there's enough flow to cover all of my electricity needs, but it ought to be fairly close.
But there's more. The water in those creeks is cold — very cold. Where I live, the air is hot — very hot. Air conditioning with electricity is expensive — very expensive. However, pumping cold water through a car radiator with a fan blowing over it is cheap — very cheap. In other words, I'm going to have nearly free air conditioning.
In addition, by building a water still, I can get potable water without drilling a well. The energy costs are much higher, but the up-front costs are much lower. So I can start with a still, and drill a well later. Can I make a still which provides enough water to live on? I don't really know, but I'm going to find out!
The pond is interesting for several reasons. First, it means that I can stock it with fish and have a free source of meat. Next, it means that I can use pumped-storage electricity: pump water from a low reservoir up to the pond whenever I'm using less electricity than my (solar, wind, hydro) system is producing. Later, when I need more electricity than my system can produce, I drain the pond and let the water flow through a turbine, thereby meeting my immediate need. On top of that, I would really like to get a kayak or a canoe and just go sit on the water. I don't really like to fish, so sitting on the water will generally be a "read in solitude" thing. Yeah, I know I just said I want to stock the pond w/ fish... I like eating fish, not catching fish, especially with a pole, hook, line, and sinker. There's a reason man invented nets...
Anyway, I'm embarking on this project. It's going to be dirty, expensive, exhausting, and hopefully very fun. We shall see.
When I say "build a castle," I really mean "stick-build a house which looks an awful lot like a castle." I intend to do most of the construction myself, partly to reduce the cost, and partly because I enjoy construction.
There are some interesting features of the land I purchased which make this endeavor something that is not entirely unreasonable:
- It is full of oak, cypress, and pine.
- It has two creeks which converge near its border.
- There is a pond at the highest point on the property.
Oak and cypress are materials which are fairly expensive. At the Home Depot, a 1/2"x2"x4' board of red oak is $4.12 right now. That's 1/3 board feet, so $12.36 per board-foot. An 8 ft 2x4, on the other hand, is 3-1/2 board-feet, and costs $3.12, so $0.89 per board foot. That's a 13.86:1 ratio. A 32-foot long, 8" diameter log is 9650 cubic inches (32*12*8*π), or 67 board feet. That's about $800.00, or 265 pine 2x4's (!!). At 16" centers, those 2x4s would cover 353 feet of distance (not including sill plate or top plate.) That's enough to frame all of the exterior walls on one floor of my current plan. Having a source of oak is clearly a Good Thing™.
The creeks. Ahhh, the sweet sweet running water. That's pure gold, right there. First, and most importantly, local laws allow me to dam them up, thereby turning them from creeks into a moat. I'll have to cut a bit on one side of the property to make the moat completely surround the castle, but I'll still have an honest-to-goodness moat. By having a dam, I can direct the flow through a turbine and get electricity. I don't think there's enough flow to cover all of my electricity needs, but it ought to be fairly close.
But there's more. The water in those creeks is cold — very cold. Where I live, the air is hot — very hot. Air conditioning with electricity is expensive — very expensive. However, pumping cold water through a car radiator with a fan blowing over it is cheap — very cheap. In other words, I'm going to have nearly free air conditioning.
In addition, by building a water still, I can get potable water without drilling a well. The energy costs are much higher, but the up-front costs are much lower. So I can start with a still, and drill a well later. Can I make a still which provides enough water to live on? I don't really know, but I'm going to find out!
The pond is interesting for several reasons. First, it means that I can stock it with fish and have a free source of meat. Next, it means that I can use pumped-storage electricity: pump water from a low reservoir up to the pond whenever I'm using less electricity than my (solar, wind, hydro) system is producing. Later, when I need more electricity than my system can produce, I drain the pond and let the water flow through a turbine, thereby meeting my immediate need. On top of that, I would really like to get a kayak or a canoe and just go sit on the water. I don't really like to fish, so sitting on the water will generally be a "read in solitude" thing. Yeah, I know I just said I want to stock the pond w/ fish... I like eating fish, not catching fish, especially with a pole, hook, line, and sinker. There's a reason man invented nets...
Anyway, I'm embarking on this project. It's going to be dirty, expensive, exhausting, and hopefully very fun. We shall see.
Subscribe to:
Posts (Atom)