If you do something stupid with an electronic power supply, sometimes they are equipped to sense it and throw a crowbar across the output to protect the insides. Picture a Jacob's Ladder running, an evil scientist cackling maniacally, and a hero sneaking through the shadows carrying a crowbar--he then poises to cast his payload into the crackling storm of electricity--
If you're reading my blog, you probably know by now that something rather technical shows up once in a while. This is one of those posts.
I'm checking out a Con Avionics HS26-13.5 analog power supply. It weighs a good 30 lbs. and is rated at 24-28 VDC at 13.5 A. This particular unit has been dropped on its head. The front right top corner has been displaced a good inch into the volume of the machine.
I could tell the case would short a couple of contacts inside if it were powered up, so I resolved to get the cover off. Well, first thing to do is take an odd silver (matte aluminum) box off the back. It's a -Con Avionics OVH26-13.5. Google says "con avionics ovh26-13.5" doesn't exist. At the moment I think it's merely a sophisticated external overvoltage crowbar circuit.
It's connected across the output. It has large bolt-mounted diodes or SCRs of some kind and an MCR648-2 mounted on the outside on a moderate heat sink. The supply is "HS26-13.5" while the attachment is "OVH26-13.5," so it seems to me we have Over Voltage Handler or somesuch with a common voltage-current pair with the supply proper.
Thursday, February 10, 2011
Wednesday, February 9, 2011
Solfeg
After listening to his music tutor sing a long and clear note, a novice innocently asked him, "is that so?"
"Nah," the Master replied, "It's just me."
Realizing his pun had not gone undetected, "D'oh!" slipped past the novice's filter.
The Master shook his head at what a ray of light this young whippersnapper was.
Notably, he thought, This is fa' better then being T'd off. Lahts bettah.
Does that bring us back to sew?
Not without a bit more doh.
"Nah," the Master replied, "It's just me."
Realizing his pun had not gone undetected, "D'oh!" slipped past the novice's filter.
The Master shook his head at what a ray of light this young whippersnapper was.
Notably, he thought, This is fa' better then being T'd off. Lahts bettah.
Does that bring us back to sew?
Not without a bit more doh.
Saturday, February 5, 2011
Making Kinections
So, I'm the proud owner of a brand new XBox 360 Kinect bundle.
I'm kinda giddy about it.
I'm quite happy about many other things too, like my internship.
See, internally it's a specialized PC (i386-compatible? ia64?) architecture. It plays fun games. It's one of the later revisions of the hardware, so ring-of-death and other issues have been worked out by all those who came before me. (Thanks!)
Also, the Kinect (with a $35 addition) can plug into the PC and use the libFreeNect driver to pull the 3-D and other informations out of it that the games on the 'Box can. See, I don't think dancing in place in front of a camera in order to make a figure on screen pretend to imitate me is going to be much fun--but driver and algorithm development, THAT will be awesome. :)D
I'm also pondering looking into rooting the box and installing Linux--but that'd require a hard drive as the installed nonvolatile memory is only 4GB. Also, I value it's Halo capabilities a touch more than I value its Linux or computing power. (What's in those things, anyway?) (I had to look it up. Check out the wikipedia article on its internals. Apparently it would be sweet for raw power's sake.) Thus, I probably will put that task off for quite some time. (I really wouldn't mind running Windows on it--I'd just love to have a general-purpose 3-core 64-bit PPC machine of my own.)
Biggest uses for it? Playing DVDs, playing games lots of people can play, and hacking the Kinect. That's about it. :)
(Microsoft, will you Please please please pretty please allow Steam to operate on XBox Live? I might even consider that grounds on which to get a paid subscription.:P)
I'm kinda giddy about it.
I'm quite happy about many other things too, like my internship.
See, internally it's a specialized PC (i386-compatible? ia64?) architecture. It plays fun games. It's one of the later revisions of the hardware, so ring-of-death and other issues have been worked out by all those who came before me. (Thanks!)
Also, the Kinect (with a $35 addition) can plug into the PC and use the libFreeNect driver to pull the 3-D and other informations out of it that the games on the 'Box can. See, I don't think dancing in place in front of a camera in order to make a figure on screen pretend to imitate me is going to be much fun--but driver and algorithm development, THAT will be awesome. :)D
I'm also pondering looking into rooting the box and installing Linux--but that'd require a hard drive as the installed nonvolatile memory is only 4GB. Also, I value it's Halo capabilities a touch more than I value its Linux or computing power. (What's in those things, anyway?) (I had to look it up. Check out the wikipedia article on its internals. Apparently it would be sweet for raw power's sake.) Thus, I probably will put that task off for quite some time. (I really wouldn't mind running Windows on it--I'd just love to have a general-purpose 3-core 64-bit PPC machine of my own.)
Biggest uses for it? Playing DVDs, playing games lots of people can play, and hacking the Kinect. That's about it. :)
(Microsoft, will you Please please please pretty please allow Steam to operate on XBox Live? I might even consider that grounds on which to get a paid subscription.:P)
Wednesday, January 12, 2011
The Crossing
Heh. I just wanted a melodramatic title. :)
I was traversing the parking lot today and ran into a friend of mine. After exchanging greetings and customary hugs, she and her friend went their way and I went mine. Despedidas were then exchanged, and as the distance between us increased a car passed.
So what.
Well, this car passing completely annihilated (to my admittedly faulty hearing) what she said next.
Well? Shout "What?" or "Come again?"
Nah.
"POTATO!!!"
The response?
"I'm glad you got that!"
Thus ended the conversation. I'm still not sure what I got.
Amusing?
Yes.
I was traversing the parking lot today and ran into a friend of mine. After exchanging greetings and customary hugs, she and her friend went their way and I went mine. Despedidas were then exchanged, and as the distance between us increased a car passed.
So what.
Well, this car passing completely annihilated (to my admittedly faulty hearing) what she said next.
Well? Shout "What?" or "Come again?"
Nah.
"POTATO!!!"
The response?
"I'm glad you got that!"
Thus ended the conversation. I'm still not sure what I got.
Amusing?
Yes.
Friday, January 7, 2011
Odd Fellow
I don't often notice little things, especially little things about other people. I'll notice odd peculiarities in any of a number of circumstances, but I tend to avoid scrutinizing people. (Barring infosec transactions...then my CS nerd gets all excited.)
I sat in the lobby of an office today. Across from me was a kid with a light backpack and a ski jacket. He had the gaunt, taught face of someone historically loaded with worry but not yet accustomed to it. The load had yet to etch its indelible marks into his features.
He seemed to be meandering aimlessly without moving a muscle. Being in that place seemed important to him, though I couldn't tell why.
I think he noticed me. It's uncertain when a person's eyes are that glazed over just what is or isn't happening between the ears. The eyes also had a myopic cant to them; the world wasn't in focus. It wasn't a lack of physical focus only--it seemed like his next objective was clouded while his overall course was obscured completely.
Definitely muttering under his breath, that one. Some phrases encouraging himself toward some far-off unknown goal, some lambasting some turn of fortune or choice made.
There was a slackness to his posture that was odd. It conveyed that he might let go of the coat he was holding at any time, and that at the same time he might lose his seemingly tenuous connection with reality.
This guy didn't take care of himself terribly well. His gait was a bit uneven, and from the stoop of his shoulders his physical frame was an added layer of weight pressed under all the other loads he carried.
You could almost feel the warping of spacetime as his thoughts raced in tight loops of limited information, lack of perspective, fractured self-confidence, and timorous feelings. Occasionally he'd shudder out a sigh, I suppose out of sheer frustration with how limited he was in just grasping whatever the matter was.
Just after these brief moments a clarity would cross his face, and he would try to brook time and space for a moment and then rapidly descend into another spiral of angst and worry, frustration and annoyance.
His confusion increased when his test results came back.
After heaving a sigh he left with an air of determined resignation. A hint of frustration and confusion wafted in with that air, and perhaps an underlying layer of insanity.
Maybe someday I'll bump into that kid and ask what happened, where all his energies wound up. I hope so. I also hope things work out for him.
I sat in the lobby of an office today. Across from me was a kid with a light backpack and a ski jacket. He had the gaunt, taught face of someone historically loaded with worry but not yet accustomed to it. The load had yet to etch its indelible marks into his features.
He seemed to be meandering aimlessly without moving a muscle. Being in that place seemed important to him, though I couldn't tell why.
I think he noticed me. It's uncertain when a person's eyes are that glazed over just what is or isn't happening between the ears. The eyes also had a myopic cant to them; the world wasn't in focus. It wasn't a lack of physical focus only--it seemed like his next objective was clouded while his overall course was obscured completely.
Definitely muttering under his breath, that one. Some phrases encouraging himself toward some far-off unknown goal, some lambasting some turn of fortune or choice made.
There was a slackness to his posture that was odd. It conveyed that he might let go of the coat he was holding at any time, and that at the same time he might lose his seemingly tenuous connection with reality.
This guy didn't take care of himself terribly well. His gait was a bit uneven, and from the stoop of his shoulders his physical frame was an added layer of weight pressed under all the other loads he carried.
You could almost feel the warping of spacetime as his thoughts raced in tight loops of limited information, lack of perspective, fractured self-confidence, and timorous feelings. Occasionally he'd shudder out a sigh, I suppose out of sheer frustration with how limited he was in just grasping whatever the matter was.
Just after these brief moments a clarity would cross his face, and he would try to brook time and space for a moment and then rapidly descend into another spiral of angst and worry, frustration and annoyance.
His confusion increased when his test results came back.
After heaving a sigh he left with an air of determined resignation. A hint of frustration and confusion wafted in with that air, and perhaps an underlying layer of insanity.
Maybe someday I'll bump into that kid and ask what happened, where all his energies wound up. I hope so. I also hope things work out for him.
Thursday, December 30, 2010
Jonny the Jalopy--on a stick
A few of you will understand where I got that name...
So driving stick is fun. :) Mind you, it's also a pain, but today's experience wasn't too bad.
Before my first lesson earlier this year I made sure to get my dad to explain the clutch to me. No, not just what "in" and "out" mean (which are actually highly variable), but blast it, give me a mechanical drawing, principles of operation, potential quirks due to emergent behaviors of a simple system...a basic understanding of the beast. That had been the most intimidating part. After a session with my dad, a chalkboard, and some dumb ;) questions, I thought I had it. At least kind of. (Turns out the transmission has some black magic of its own: synchros.)
My first time behind the wheel of a stick was interesting. I learned a lot but didn't go very far.
Last driving practice on a manual was a bit rough. I killed it once, had a nasty bucking session (match power feed with the time constant of the flywheel mass and clutch spring constant and voila: you're sitting on a driven oscillator), and putted around the neighborhood for about 5 or 10 min. before both my instructor (Mom or brother; don't recall) were too fed up with the process and I jerkily settled the car in the driveway. This session was important, but I butted up against the session restriction: no "high" (read: 3rd or higher) gears until you master starting and stopping. You Will Master The Clutch And First Gear Or You Will Not Do Anything Cool. 'Master,' mind you, not 'get passing good with.'
Thus started today. My dad and I decided to go to the temple. We then decided to take the stick. I hadn't 'mastered' starting, let alone passing the 'sit stationary pointed uphill using just the gas and clutch to stay put' test my mom required of my younger brother before letting him hit the highway, so I figured I'd be the passenger.
"You wanna drive?" Dad asked?
"Um, sure, but we'll have to hit a driveway and..." So I explained.
"Ok. Sounds good." His response was nice; I'd get some practice in. :D
I wandered through back roads leading to the latest possible highway entrance, only managing to buck significantly once and kill it once. "Par with the last session. Stop while you're ahead, K?" I thought to myself. Well, about halfway through the leg of the trip prior to the highway, I've been up to fourth gear and started and stopped a few times without much trouble, So, methinks, I'm doing alright."
About now Dad springs on me the idea that highway driving isn't much different. Just get into 5th gear, handle the throttle differently, and you're good. If you're comfortable with open freeway driving in an automatic then driving a stick isn't much different.
He was right.
Aside from downshifting during on ramps, using the engine to brake, and some other tricks you pick up on the smaller roads, it was. I made it to the temple and back (about 20 min.) safely. While I do still have some work to do on my starting, all the time in higher gears and actually moving gave me a lot more confidence so that I could talk shop with my dad as he described how to improve. (That's where the driven oscillator conversation happened. Turns out the idea is to pick a different point to start feeling for the catching sensation or use a different initial motor speed.) I even started to make superfluous complete stops so that I could start implementing the changes. While I do still have some work to do on my starting, all the time in higher gears and actually moving gave me a lot more confidence in my ability to drive a stick. This, in turn, made refining my skills a much more pleasant and much less nerve-wracking experience.
Eat that, last driving session.
So driving stick is fun. :) Mind you, it's also a pain, but today's experience wasn't too bad.
Before my first lesson earlier this year I made sure to get my dad to explain the clutch to me. No, not just what "in" and "out" mean (which are actually highly variable), but blast it, give me a mechanical drawing, principles of operation, potential quirks due to emergent behaviors of a simple system...a basic understanding of the beast. That had been the most intimidating part. After a session with my dad, a chalkboard, and some dumb ;) questions, I thought I had it. At least kind of. (Turns out the transmission has some black magic of its own: synchros.)
My first time behind the wheel of a stick was interesting. I learned a lot but didn't go very far.
Last driving practice on a manual was a bit rough. I killed it once, had a nasty bucking session (match power feed with the time constant of the flywheel mass and clutch spring constant and voila: you're sitting on a driven oscillator), and putted around the neighborhood for about 5 or 10 min. before both my instructor (Mom or brother; don't recall) were too fed up with the process and I jerkily settled the car in the driveway. This session was important, but I butted up against the session restriction: no "high" (read: 3rd or higher) gears until you master starting and stopping. You Will Master The Clutch And First Gear Or You Will Not Do Anything Cool. 'Master,' mind you, not 'get passing good with.'
Thus started today. My dad and I decided to go to the temple. We then decided to take the stick. I hadn't 'mastered' starting, let alone passing the 'sit stationary pointed uphill using just the gas and clutch to stay put' test my mom required of my younger brother before letting him hit the highway, so I figured I'd be the passenger.
"You wanna drive?" Dad asked?
"Um, sure, but we'll have to hit a driveway and..." So I explained.
"Ok. Sounds good." His response was nice; I'd get some practice in. :D
I wandered through back roads leading to the latest possible highway entrance, only managing to buck significantly once and kill it once. "Par with the last session. Stop while you're ahead, K?" I thought to myself. Well, about halfway through the leg of the trip prior to the highway, I've been up to fourth gear and started and stopped a few times without much trouble, So, methinks, I'm doing alright."
About now Dad springs on me the idea that highway driving isn't much different. Just get into 5th gear, handle the throttle differently, and you're good. If you're comfortable with open freeway driving in an automatic then driving a stick isn't much different.
He was right.
Aside from downshifting during on ramps, using the engine to brake, and some other tricks you pick up on the smaller roads, it was. I made it to the temple and back (about 20 min.) safely. While I do still have some work to do on my starting, all the time in higher gears and actually moving gave me a lot more confidence so that I could talk shop with my dad as he described how to improve. (That's where the driven oscillator conversation happened. Turns out the idea is to pick a different point to start feeling for the catching sensation or use a different initial motor speed.) I even started to make superfluous complete stops so that I could start implementing the changes. While I do still have some work to do on my starting, all the time in higher gears and actually moving gave me a lot more confidence in my ability to drive a stick. This, in turn, made refining my skills a much more pleasant and much less nerve-wracking experience.
Eat that, last driving session.
Friday, December 17, 2010
Happy Final Exit
That sounds incredibly deep and of great import.
It's not.
It's just that I was afraid of my Mathematical Proofs class final, as I hadn't done any homework the last two weeks of class and we covered a topic that still kinda confuses me--delta epsilon proofs. I crammed for an hour prior. It seemed hopeless; I'd done well on previous tests, but the sheer volume of material and the emphasis on this last concept worried me. I forced myself to complete a d-e proof end-to-end. It was a simple one for a wee little linear function.
Lo and behold, as promised by the professor, it was on the test. Only it was a quadratic this time. After some finagling and tweaking, I found a workable delta. I even had time to double check it. All the other proofs weren't terribly worrisome either: even the inductive proof was straight induction and algebra.
I says to me, "Self, you oughta be proud of yourself. You did great. You had an answer for every question; one that felt right, even!" "Well," says I, "pride is dumb. I'll be humbled in a minute here when I see my multiple-choice score. Some of those were tricky and I'm not the best at details." "Well, self, you'll see."
Down the stairs, out the door. Pause, assess high-load layout and traffic patterns, shuffle over and look at the score monitor.
"You? 100%"
W000000000000000000T!
Hoorah!
Erm, :D
Who do I tell?
Meh. Nobody.
I could blog about it...
Happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy!!!!!!!!!!!!!!!!!!!!!!!!!!1!!!!one!!!!!!!!!
Eat that final final from the semester of internal pwnage and panzerfication! I can prove stuff!
Now you've shared in that happy moment. :D
It's not.
It's just that I was afraid of my Mathematical Proofs class final, as I hadn't done any homework the last two weeks of class and we covered a topic that still kinda confuses me--delta epsilon proofs. I crammed for an hour prior. It seemed hopeless; I'd done well on previous tests, but the sheer volume of material and the emphasis on this last concept worried me. I forced myself to complete a d-e proof end-to-end. It was a simple one for a wee little linear function.
Lo and behold, as promised by the professor, it was on the test. Only it was a quadratic this time. After some finagling and tweaking, I found a workable delta. I even had time to double check it. All the other proofs weren't terribly worrisome either: even the inductive proof was straight induction and algebra.
I says to me, "Self, you oughta be proud of yourself. You did great. You had an answer for every question; one that felt right, even!" "Well," says I, "pride is dumb. I'll be humbled in a minute here when I see my multiple-choice score. Some of those were tricky and I'm not the best at details." "Well, self, you'll see."
Down the stairs, out the door. Pause, assess high-load layout and traffic patterns, shuffle over and look at the score monitor.
"You? 100%"
W000000000000000000T!
Hoorah!
Erm, :D
Who do I tell?
Meh. Nobody.
I could blog about it...
Happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy happy!!!!!!!!!!!!!!!!!!!!!!!!!!1!!!!one!!!!!!!!!
Eat that final final from the semester of internal pwnage and panzerfication! I can prove stuff!
Now you've shared in that happy moment. :D
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