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Comment: I miss 1970s tech. (Score 2) 158 158

I started out with a TRS-80 Model I in high school. I spent a lot of time on that machine, and applied a lot of the "canned hacks" developed by others -- add-on hardware better than that Radio Shack sold, a memory remapper to let it run CP/M, soldering in another 1024x1 RAM chip to support lowercase video, jumpering the clock divider chain to effectively overclock the CPU, and so on.

Eventually, I noticed that I was starting to have wrist problems, especially when I used WordStar -- that WP used the non-existent Control key quite a lot, and the CP/M port mapped it to one of the arrow keys, which was an ergonomic nightmare. But I happened to find a pair of foot switches on clearance at Radio Shack, pre-wired to mini audio plugs. I drilled two holes in my system unit, mounted two mini jacks, and wired them to the keyboard in the same position as the shift key and that arrow key. Stomp-K-D for the win! My wrists were better in no time.

Later, I got a state-of-the-art 1200bps modem, but my poor terminal program couldn't keep up. Any time the screen had to scroll, I dropped characters. The solution: I rewired the 40Hz real-time interrupt to fire at 160Hz, and wrote a little interrupt-driven driver to catch and buffer characters coming in over the RS232 interface. It was completely bulletproof. Unfortunately, it also sped up the keyboard timing (repeat delay and rate) by 4x in CP/M.

I guess the biggest hack, though, was building a full character-based video display subsystem that hung off the expansion port. Forty or fifty SS/MS LSTTL packages spread across eight or ten solderless breadboards, with a couple of static RAM chips thrown in for character generation and storage. It ended up being something like 30 lines of 100 characters, comfortably larger than the original 16x64 display or even the 24x80 displays in the computer labs, and each cell was 8x16 pixels, so they were nicely readable characters. Luxury. I used that "in production" for a year or two, until I managed to land a Lisa.

Comment: And yet, here we are on the Internet... (Score 1) 194 194

...reading your op-ed (as opposed to, oh, I don't know, an actual report containing actual facts).

One of the unique characteristics of the Internet is that it provides a way to monetize tiny minority tastes. That way, bozos can produce books or videos on "Down is Up", "Beanie Babies: The New Future-Proof Investment", or "The Unexpected Triumph of Old Media in the Digital Age", and find enough paying customers to make it worth their while.

Comment: Hypersupervised programming? (Score 5, Insightful) 126 126

Golly! How do you suppose that having one person at a time writing code, with the rest of the team effectively doing simultaneous code review, magically produces "fewer features" but "better code quality" than having everybody writing code, then throwing it together and maybe doing a cursory bit of code review at the end?

Next, you'll be telling me that having one or two testers per developer produces better-quality software than spending all your money on developers so you can "get more features".

Comment: Never thought of plasma sheath as Faraday cage... (Score 1) 62 62

Turning the shield (conductive layer around the craft) into an antenna? I like this idea. And with the full paper freely available through the link in the source article, I could in principle learn more -- if only my math and EM physics were up to it. Sigh.

Comment: Re:skip the gender (Score 1) 412 412

Some of us are heteroromantic, biromantic, homoromantic, panromantic, demiromantic, or even aromantic.

We realize that different cultures have different hygiene practices, but really, can't you put on a bit of deodorant in the morning?

Oh, wait. Never mind.

Comment: Then why say "you" instead of "I"? (Score 2, Insightful) 412 412

"I was just being honest about my own shortcomings -- by talking about what 'you' do when there are women in the lab. 'You', of course, being a straight male, because duh, who else would I be bothering to talk to about science?"

Comment: Re:Cool, but way overstated. (Score 1) 47 47

It almost seems like you're interpreting "UV-C" to include the range from 360-380nm. There are apparently some results indicating that emitters in this range can be germicidal, if you use enough power and enough exposure time; is that where our disconnect is arising?

The Nichia page you linked lists only longwave emitters, with 365nm the shortest wavelength. I'm sure they have shortwave emitters, and maybe even samples for some of them, but if they aren't listed on the Web site, I'm not confident how much of a "product" they are to date.

Cree has never sold UV-C LEDs, as far as I can tell. They sold longwave emitters for a while, but then discontinued them.

I spent some time prowling around HaSun's list of UV LEDs. I haven't waded through every listing, but most of the emitters under 300nm seem to be in the range of 1.5mW or less; I found one ("New Technology!!!") that claimed 0.2-0.3W optical output power in the specs, but in the chart below, it said 0.2-0.3mW. WIth forward current of 20 mA and forward voltage of 7-8.5 V, getting out 200mW of anything would be quite the trick.

Again, we can see that the shortwave emitters exist, but it doesn't look like they're common enough or powerful enough to start appearing in products yet.

Comment: Re:Yes and no (Score 2) 47 47

I'm flattered that you're reposting my links from below, but I think you're missing GP's point. None of those three links appear to describe units that are "commonly available" -- in one case, it's only engineering samples, and in none of the links do they say a word about pricing or actual availability (the last one claims "mass production", but doesn't back it up).

"UV lasers" are mostly 405nm, not really UV, and the quantum dots from TFA are firmly in longwave territory. So, GP's points stand.

Comment: Re:Water sterilization is the big thing here (Score 1) 47 47

Actually, 420 would be a bit too violet for this application. Cree's XR-E emitters seem to use a blue emitter centered around 450nm (pdf), coupled with a yellow phosphor -- blue + yellow = blue + (green + red) = white. That's how most "white" LEDs work. If you used a shorter-wavelength emitter, you'd need to downconvert all its output power, losing efficiency. By using a blue emitter, you pass some of the blue light, and downconvert just enough of it to yield the perceived color temperature you want.

Comment: Re:Cool, but way overstated. (Score 3, Informative) 47 47

Links, please? Last I checked, UV-C emitting diodes were essentially experimental items, with output power below 1mW, and sky-high prices. Feel free to ridicule me mercilessly if I'm wrong, but please post links; I'm a lot more interested in learning about UV-C emitters than in defending my hypothetical reputation.

This page crows about UV-C LEDs, but is conspicuously silent about output power (beyond calling it "stable"), availability, or price.

This page claims 5-10mW per device, adding that "limited release engineering samples are available today." The datasheet is mum on device lifespan.

This looks more promising -- 10mW per device, 10,000 hour life -- but where are the products, and where are the prices?

Obviously, I could be missing some products that are already shipping. But if you actually have a bank of UV-C LEDs that's been putting out enough power to kill algae in your aquarium for the last five years, it looks like a lot of electronics and physics journals would be interested in hearing from you. And so, as I said, would I.

Comment: Cool, but way overstated. (Score 3, Informative) 47 47

We already have robust conventional LEDs that emit high power at comparable wavelengths (considered "longwave UV"). This wavelength is not especially useful for purification and sterilization. For that, you need UVC, in the range of 250nm and below. That's still difficult with anything other than a fluorescent emitter or an arc; solid-state emitters in that range have very low power and short life, at least last time I checked.

The other problem with very short wavelengths is finding packaging materials that will transmit and withstand them over long periods. Even longwave UV will cause materials to deteriorate over the lifespan of a solid-state emitter; UVC is much more harsh.

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