The Rodent's Burrow

A couple of weeks ago I picked up a Maglite LED flashlight, since I'm pretty fed up with the flakiness of my Coast ones. It wasn't until after I got home that I noticed that the package said, in REALLY BIG LETTERS, that it uses a "3-Watt LED!"

It also runs on two AA-sized batteries. Which are 1.5VDC apiece. Now, unless I'm totally fried, or things have changed since the dark ages wherein I tool electronics, Ohm's Law sez that in order to produce 3 watts of power, at 2 × 1.5VDC, there needs to be 1 amp of current flowing.

This seems unlikely to me on several levels. Trying to pull 1'000mA out of two AA batteries is going to be a challenge, and one that's over pretty quick. And pushing 1'000mA through a normal (or even super-bright) LED is going to be an experience that'll be over even quicker.

So what the hell are they trying to say here? Other than razzle-dazzle the ignorant customer with Something Shiny™.. Maglite, I'm disappointed in you.

Technorati tags: Maglite  LED 

Scribed by coar at 2008-07-01 14:42:47 at 2008-07-01 14:42:47 (0 items in this thread)

Ever since I upgraded the firmware in my Nikon D70 to version 2.0, I can no longer mount the camera's CF card as a USB disk via a USB cable direct to the camera. (Yes, I know that's a slooow method, but I don't particularly care to lug card readers around when I travel.) What's worse is that so far I haven't been able to find any description of the problem being experienced by anyone else.

In Windows all that shows up is 'USB device.' And in Linux, the system log shows lots of messages like

Jun 29 13:06:52 nodename kernel: usb 5-2: new full speed USB device using uhci_hcd and address 25
Jun 29 13:06:52 nodename kernel: usb 5-2: device not accepting address 25, error -71

I haven't started looking for those messages yet; I've been busy with actually taking the photos.

It'll probably be something simple. This used to be a no-brainer; plug it in and there it was. Now the 'upgrade' has borked it. Bah.

Technorati tags: Nikon  D70  firmware  upgrade  USB  mass+storage 

Scribed by coar at 2008-06-29 22:17:51 at 2008-06-29 22:17:51 (0 items in this thread)

We decided to take a couple of days' holiday this weekend, as a sort of belated anniversary gift to ourselves. (Twenty four years a fortnight ago.) This weekend because that was when we could get one of the fancy rooms at the hotel, with a Jacuzzi. So now we're on the ninth floor of an oceanfront hotel in Carolina Beach, North Carolina. All the rooms here are oceanfront, so we didn't have to worry about getting tricked. (We found out two decades ago that 'ocean view' can mean 'you can see the ocean from your balcony if you lean out dangerously far, crane your neck, and squint — and if the weather conditions are favourable.')

We arrived yesterday afternoon, and around sunset we walked down to the beach and along the water. I saw some telltale signs, dug into the sand in a retreating wave, and pulled out a couple of sand fleas. Although there is a biting critter found on beaches that goes by the same name, the ones in the surf are harmless and are not fleas at all; they're related to the crab. Digging up sand fleas and coquinas was a fun part of my younger years, so it was great to do it again.

Last night was kinda restless. At one point the SBH woke me up to see a line of thunderstorms marching along offshore; the lightning displays were impressive, but we couldn't hear the thunder over the surf. Looking at the weather site, finding out that the storms we were looking at were actually about fifty miles away probably had something to do with them being fairly silent, too. And at some point later in the night (or early in the morning, I suppose) I woke her up because the crescent moon (one of her favourite phases) had risen and was shining across the water on one side of the view, while the storm line was still flickering and grumbling along on the other side.

By that time it was close enough to dawn to wait, so we did. I haven't seen the Sun come up over the ocean in decades; I'd forgotten how delightful it could be.

Technorati tags: Carolina+Beach  North+Carolina  Atlantic+Ocean  Atlantic  sunrise  holiday  coast 

Scribed by coar at 2008-06-29 15:19:53 at 2008-06-29 15:19:53 (0 items in this thread)

This basically says it all: Opinion of the Court. It's 157 pages long, and the opinion was far from unanimous.

Held:

1. The Second Amendment protects an individual right to possess a firearm unconnected with service in a militia, and to use that arm for traditionally lawful purposes, such as self-defense within the home.

It doesn't mean you can pack a flamethrower or nonchalantly walk about with a bandolier of hydrazine grenades, but it should finally put to rest all the bullshit about referring to the National Guard.

Technorati tags: U.S.+Constitution  Second+Amendment  2nd+Amendment  rights  freedom  law  Washington+D.C.  gun+ban 

Scribed by coar at 2008-06-26 13:22:27 at 2008-06-26 13:22:27 (0 items in this thread)

Now that I've got the mill and lathe in usable shape, it's time to start, er, using them. Of course the first things that come out of them are tooling and improvements for the machines themselves, such as an arbor for my diamond saw so I can cut more meteorite dice, a chip guard for the lathe's carriage handwheel gearing, an adapter sleeve to let me use my 0.375" boring bars in my 0.500" boring head, an axis marker for the lathe, and so on. Still on the soon-to-make list are a saddle clamp, a cam-lock for the tailstock, and a carriage stop that can shut off power when reached. And, of course, more dice, an optical punch, a 2" centripetal fan, a Ranque-Hilsch vortex tube, and I want to try cutting a dodecahedron.

As usual, I'm putting photos online at my Flickr pages. Check out the 'Mini-mill' and 'Mini-lathe' sets.

Technorati tags: mini-lathe  mini-mill 

Scribed by coar at 2008-06-25 15:57:17 at 2008-06-25 15:57:17 (0 items in this thread)

It's been a while since I blogged anything, primarily because every time I think of something I'm not where I can do anything about it — and then I've forgotten by the time I can post something.

So I'd better do little postinglets as I can. Starting now.

I've been diagnosed with ADHD, which I supposed explains a lot — such as the condition of my office. :-) It's a physiological/neurological condition, and right now we're working out the correct dosage of medication to address the symptoms. Supposedly once we've zoned in on them, I'll be a lot more able to focus on things for longer periods of time, and deal better with activities I find tedious or tiresome.

Technorati tags: ADHD  ADD 

Scribed by coar at 2008-06-25 12:13:32 at 2008-06-25 12:13:32 (0 items in this thread)

Papa John's pizza chain sends us regular email about specials. This week it was to announce their new (?) whole-wheat pizza. Since we're currently trying to eat more whole-grain food, and there was The Whole Wheat Pizza Factory in Amherst where we went to university, we thought we'd give it a try.

In a word: yuck.

Yes, that rhymes with 'suck.' It was awful. We ended up scraping the toppings off and eating them plain (which left the crust looking like a sad poster-child for terminal acne). As soon as we were done I rushed to get the remains out of the house and into the dumpster.

YMMV. Try it for yourself if you like.

Don't say I didn't warn you, though.

Technorati tags: pizza  Papa+John 

Scribed by coar at 2008-05-27 16:10:45 at 2008-05-27 16:10:45 (0 items in this thread)

I used to think a microsecond (µS) was a really, really tiny interval, at least for purposes of any electronic doodads I'd cobble together. That is, if you performed operations at a 1MHz rate, you'd always have plenty of ticks available for a task. Doing a little calculation based on a project I'm considering has enlightened me otherwise.

Tomorrow the shim stock arrives and I can align my lathe and tram my mill, and then away to the races. I have over a dozen projects in mind, mostly improvements and modifications to the machines themselves, but one or two actually useful in other contexts. For instance, making a flagpole bracket — by Sunday night — so we can hang the new flag on Memorial Day, and the dice made from nickel-iron meteorites that I'm trying to sell on eBay.

One of the former type is whacking together a tachometer for the lathe. Looking round the Web, most of the custom-machined versions seem to focus on eyeballing something that uses the spindle's RPM and the household AC (in the form of fluorescent lighting) to give different appearances at different speeds. Aside from the fact that one of the safety rules I learned decades ago is to never use machine tools under a strobing lighting source, I also don't happen to have any fluorescent lights in my 'shop.' (Nice way to stay on the high ground, there.) So I'm thinking of actually using some of these photointerruptors I've scavenged from printers, making an interruptor disc to put on the spindle in the gearbox, and process the results using a PIC circuit.

Which is where the microseconds come in. I was thinking of including a 'keybounce' delay to ensure noiseless readings from the photointerruptor, and did a little math to see how long it should be. Ten milliseconds, maybe? For human-pressed key, possibly, but not for this. Assuming a top measurable RPM of 3'000, and an interruptor disc with 16 holes or gaps, there are only 20µS between signals. That's not much time for anything, especially keybounce suppression, when your microcontroller has a 1MHz internal instruction clock.

So a microsecond tick really isn't that small after all. Yeah, I know that gigabit processors and gigabit Ethernet require timeslicing to a degree orders of magnitude more fine, but, see, I never expected to actually make anything that needed anything shorter than a few milliseconds. Now I find that a 1MHz clock isn't really fast enough for complex computing regarding a non-extreme real-world application. So this microcontroller stuff is quite the eye-opening learning experience, and I'm glad of it.

This weekend is going to be spent getting the machines aligned, and the digital readouts installed on the mill, and maybe even making the flag bracket and an arbor for my diamond saw so I can cut more meteoric metal to make more dice.. A digital readout (DRO) installed on each axis of the mill should make for much more precise (and accurate) work; right now the backlash in the handwheels is sufficient to make me completely distrustful of the values on the dials.

The surprising — and disappointing — thing is that there was essentially no interest in the dice. I mean, they're unique! Not only are they cut and machined by hand, but as far as I know you can't get dice made out of meteoric nickel-iron anywhere else.

O well. I'm going to clean up the auctions a bit and relist them for longer than 7 days and see what happens.

Technorati tags: mini-lathe  mini-mill  alignment  tramming  PIC  microcontrollers 

Scribed by coar at 2008-05-23 23:47:35 at 2008-05-23 23:47:35 (1 item in this thread)

I've finally gotten the mini-mill and mini-lathe installed and running, though as a consequence moving around in the office has gotten much more difficult — and doing so barefoot more dangerous. I've started recording what I work on at Flickr, and the first actual product is a half-dozen 0.2" six-sided dice made from a slice of nickel-iron meteorite. You can see them in my eBay listings for as long as they're still at auction.

Here's a sample photograph; click the pic for an enlarged view.

A lot of effort went into making these, and since the dice made from stony meteorites are about U$100 apiece, when and where you can find them, I figure the even rarer ones made from meteoric metal should be more expensive.

Collect 'em all! ;-D

They weigh approximately 1 gram apiece.

Technorati tags: mini-mill  mini-lathe  Cummins  Harbor+Freigh  ToolsNow  machining  eBay 

Scribed by coar at 2008-05-15 14:52:29 at 2008-05-15 14:52:29 (0 items in this thread)

A bunch of months ago, I started getting an inkling of how short life can be, and realised there were lots of things I hadn't done but wished I had. Some of them I'll never do, but for others I can correct the omission. Three of those are hacking with chemistry, hacking with electronics, and hacking with machining. I've got a cabinet full of reagents, a case full of glassware, and some crucibles, but all I've really accomplished with them is to puddle some low-temp elements (such as tin) and smelt some very low-quality bronze. The machining I'll cover another time.

For the electronics aspect, I've always kept my hand in a little. I've got a few of those multi-drawer parts cabinets full of ICs, LEDs, transistors, resistors, capacitors, and what-not. I also have a 18" x 18" x 24" box full — and I mean full — of TTL ICs I scrounged from a computer electronics lab that went belly-up. I recently added to the instrument collection with a capacitance meter (very sweet). and a few weeks ago I buckled down and actually tried something new.

I got interested in the RepRap project at OSCON a couple of years ago (although I still haven't finished building one). That led me to get interested in stepper motors, which subsequently got me interested in microcontrollers. So I bought a programmer, some chips and crystals, and have started playing with them.

The absolutely coolest part, though basic in the extreme, was that my first microcontroller programme, in a language I'd never used before, for a device I'd never used before, to do a thing I'd never tried before — worked on the first try. Running a very close second for coolness is the fact that this is the first time, in decades of writing code, when something I wrote had an immediate and direct effect on the Real World[tm]. Admittedly it was just blinking some LEDs in a particular pattern, but it was the first time I've written software to control hardware. It wasn't a very complex programme, to be sure, but it did involve setting up a timer and handling interrupts.

One thing with which I'm not yet comfortable is the dedicated nature of microcontrollers. For years my code has been geared to 'get the job done as quickly as possible, and then relinquish the CPU.' That's the timeshare model. For microcontrollers, though, it's perfectly acceptable to stick in an infinite loop when you want to while away some wall-clock time.

Technorati tags: PIC  microcontroller  electronics 

Scribed by coar at 2008-05-02 11:06:49 at 2008-05-02 11:06:49 (0 items in this thread)