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Fish Tagged For Research Become Lunch For Gray Seals

gmarsh Re: So you use Radio instead, eh? (48 comments)

True. The ping frequency is low though (hundreds of ms between pings) which limits the modulation sidelobes, and even the initial banging on of the carrier at the beginning of each ping is fairly well bandpass filtered by the high Q of the transmitter. You can't hear a tag click/chirp/whatever if you hold it against your ear.

But if seals can detect upwards of 180khz as you're saying... Yeah, that's a problem.

about 2 months ago

Fish Tagged For Research Become Lunch For Gray Seals

gmarsh Re:So you use Radio instead, eh? (48 comments)

Going higher than 69KHz reduces the range of the tags, as higher frequencies are attenuated more in water. This means you'll need a more powerful tag (with size/battery life implications) or more deployed receivers to make the system work at a higher frequency.

The tags do produce harmonics at 138KHz/207KHz/onwards, but there's no distortion mechanism present that should allow frequencies lower than 69KHz to be created. There's no modulation done on the 69KHz carrier, the carrier is on/off keyed with time differences from one ping to the next being used to encode the tag's unique ID.

about 2 months ago

Fish Tagged For Research Become Lunch For Gray Seals

gmarsh Re:So you use Radio instead, eh? (48 comments)

Radio waves don't travel well underwater. You need stupidly low frequencies like those used for submarine communication, and you won't be able to generate those frequencies from an object that's a few cm long which means you're stuck with acoustic methods. The tags in question operate at 69KHz, which as far as I know is outside the hearing range of seals - this article makes me wonder though, I've got it bookmarked and I'll give the underlying paper a good read when I've got the time.

I'm actually an engineer at the company that makes the tags in question. We're hardly a huge corporation (100 people) and we don't have the financial clout or even any obvious reason to bankroll corrupt science - we just make scientific gear that helps scientists do their science. I wouldn't consider us to be much different from a company that makes lab coats or glassware.

about 2 months ago

Shooting At Canadian Parliament

gmarsh Re:Dear Canada.... (529 comments)

If rob ford were the PM there would be swift response.

Like what, a crack-down?

about 3 months ago

Ask Slashdot: What Recliner For a Software Developer?

gmarsh Re:Automotive bucket seat (154 comments)

I've done this - I had a Toyota Cressida chair in my house, with a SLA battery and trickle charger hooked up to run the power seat bits.

However, I'll warn that it's hard to construct such a thing without making it look ghetto. Eventually, spousal acceptance factor led to the demise of the chair.

about 5 months ago

Hack an Oscilloscope, Get a DMCA Take-Down Notice From Tektronix

gmarsh Streisand effect! (273 comments)

Funny. Yesterday we had a couple of modules come in for our MDO3K series scopes, and a co-worker and I were hypothesizing about what's in the modules. We concluded they were probably using smartcard IC's, because after all you're selling these things to engineers - people who would be smart enough to break the system if you did something cheap like a TWI EEPROM.


Thanks to this DMCA takedown, and the attention it brought, we'll be breaking out the Bus Pirate. You won't need a smartcard connector or custom PCB - a half dozen pogo pins on protoboard will do the job just fine.

about 6 months ago

Study: Stop Being So Cynical, You Could Give Yourself Dementia

gmarsh Or just maybe... (153 comments)

... dementia is the highest level you can achieve of not giving a shit about anything anymore.

about 8 months ago

Elite Violinists Can't Distinguish Between a Stradivarius and a Modern Violin

gmarsh Re:Modern audiophiles are no different. (469 comments)

Given selected music with characteristics that make a MP3 encoder generate artifacts, a good playback system, a set of headphones with good treble reproduction, and a quiet environment, I can consistently point out the difference between the uncompressed music and a 256kbps CBR MP3 made from it by carefully listening for specific artifacts.

With the majority of music in the majority of listening environments, well-encoded lossy audio content isn't noticeable. But on rare occasions it is - and I don't believe accepting that fact makes me a green-marker-in-hand audiophile.

about 10 months ago

Seagate Releases 6TB Hard Drive Sans Helium

gmarsh Re:Why not? (147 comments)

Why not?

- Requires extra machinery/infrastructure to be installed at the HD plant
- Expense of buying helium
- Expense of other drive changes required to support helium (better sealing, etc)
- Expense of licensing existing patents on helium filled drives and their manufacture.

Or perhaps they're just busy validating new drive models and their assembly line, and they'll be shipping helium filled drives shortly...

about 10 months ago

Ask Slashdot: What Games Are You Playing?

gmarsh Playin' a bunch of old games. (669 comments)

Lately I've been playing a bunch of old games, using new source ports/engines, eg:

- Duke Nukem 3D (using eduke3d engine + high resolution pack)
- Descent series (using DXX-Rebirth engine)
- Doom/Doom2 (using zdoom + high res texture pack)

I've got a never-ending fondness for these old games, and the new engines allow for an enjoyable gameplay experience - 320x200 on a 14" CRT back in the day was acceptable, not so much on a modern LCD. I can't give enough thanks to the people who run these projects.

about a year ago

Australian Team Working On Engines Without Piston Rings

gmarsh Re:A car refurbishment industry (368 comments)

My VW specialist mechanic buys older VWs, overhauls them, puts in modern engines and sells them for a nice profit. Eurovans/Wesfalias primarily, also MK1 Rabbits, MK2 golfs/jettas, caddies, etc. He can't keep up with demand.

Though, I do believe VW enthusiasts are more likely to go for such a thing - I can't see someone spending several $K getting their pontiac sunfire rebuilt.

1 year,21 days

US Light Bulb Phase-Out's Next Step Begins Next Month

gmarsh Re:Regulations a bit premature (1146 comments)

Don't buy your CFLs from a retail store. Find a local industrial supplier (eg, Grainger) that sells GE or Osram/Sylvania professional bulbs and go with them. Pick some part #s off the manufacturer websites to have ready when you walk in.

My house is full of GE FLE10HT2/2/827 CFLs, 40W equivalents that pull 10W. 2700K color temperature so their light output is easy on the eyes, and they've got a rated 12000 hour lifetime that I believe - I bought this house 6 years ago and bought a case of these bulbs to replace the existing incandescent bulbs, most of those bulbs are still in place. Indoors, they start up with about 1/4 second of lag and don't have any noticeable warmup period.

I swear by 'em. When LEDs come down to the same price I'll switch over, but I'll stick with CFLs for the time being.

about a year ago

Raspberry Pi Hits the 2 Million Mark

gmarsh Things I've used them for.. (246 comments)

- SSH to serial converter. Plug a couple of USB-RS232 cables into the Pi, plug them into serial consoles on servers/industrial equipment/whatever, and you no longer have to crouch behind a rack with a laptop whenever you need to monitor/control stuff.
- Print server for a USB laser printer
- NAS/backup machine/torrent downloader/etc
- New guts for a broken NES.

I'm sure the closed-source GPU and ARM11 CPU offend some people, but hey, it gets the job done in places I've stuffed it.

about a year ago

Kickstarter For Open Source GPU

gmarsh Re:Sounds Expensive (108 comments)

Even the highest end Virtex can't touch one of AMD/nVidia's ASICs for 3D rendering, but that isn't the target market for this design.

Here's an evaluation board for a low end FPGA chip, emulating a full 80186 PC including CPU, BIOS, keyboard controller, and VGA video:


The Cyclone II on that card is several years old, a modern equivalent of the FPGA is about $12. Now if you haul the x86 and everything else out, you've got plenty of room freed up to enhance up that VGA controller into something more modern. That's what they're going for here.

about a year ago

AMD Intentionally Added Artificial Limitations To Their HDMI Adapters

gmarsh This isn't "screw customers", this is "screw HDMI" (256 comments)

If AMD put HDMI ports on their video card, they'd have to pay licensing/royalty fees to HDMI Licensing, LLC. By only putting DVI connectors on their video cards, ATI doesn't have to pay the fee. But for the small percentage of customers who *want* HDMI, they sell the adapter and pay for the licensing costs with that instead. Since they sell far fewer adapters than cards obviously, the overall license fees paid become much less.

Presumably the EEPROM is in there because the HDMI Licensing lawyers aren't complete idiots, and required the card to make sure the adapter is licensed. Tossing a 10-cent 24LC01 or something in there with a magic byte on it probably didn't break the bank.

about a year ago

Debian Turns 20

gmarsh Re:Thanks, from an embedded designer. (121 comments)

In one case I selected an ARM chip, drew the schematic, made a set of rules for the PCB guy so the DRAM/flash interface would have good signal integrity, verified the layout and had it sent off for manufacture. Then brought the prototype board up, broke out the J-Link, verified the hardware, banged out and debugged an assembly code bootloader to initialize the ARM and pull the customized kernel out of NAND. Once I had Debian running stable on there, I handed it off to the software guys for them to do their part.

But sigh, it runs an OS, so I guess I'm not an embedded designer. Got a better job title?

about a year and a half ago

Debian Turns 20

gmarsh Thanks, from an embedded designer. (121 comments)

I've used Debian extensively in the past for embedded Linux development - I've got equipment in the field running on the x86, armel, mips and powerpc ports, from biscuit PCs running full GUIs to $10 uP's doing network-attached-widget duties in the corner of a PCB.

Debian's "non-x86" ports work well, the distribution is simple, trims down small, easily modified for whatever purpose, and it just plain gets the job done. Couldn't be happier with it.

about a year and a half ago

Why Automakers Should Stop the Infotainment Arms Race

gmarsh "Infotainment" (317 comments)

... can we stop using that word? I don't know if it's the same for anyone else, but whenever I hear that word it sounds like something between the word "synergy" and an ice pick stabbed into my ear.

about a year and a half ago

A Computer-based Smart Rifle With Incredible Accuracy, Now On Sale

gmarsh This is a good thing. (551 comments)

Speaking as an outdoorsman that has come across far too many dead/wounded deer in the woods... If a hunter using this setup is much more likely to score a single fatal shot on game, killing it with as little suffering as possible, I hope this makes it to market as quick as possible.

Around here half the deer hunters don't bother going to the shooting range, and they're god-awful shots because of it. So they end up wounding whatever deer they shoot at, and the poor thing takes off and suffers for hours until it either bleeds to death or a coyote brings it down.

about a year and a half ago

Why Your New Car's Technology Is Four Years Old

gmarsh Re:Not to mention... (455 comments)

TFA mentions at least one challenge. Kit in automobiles have to be built for extreme conditions (temperature range, vibrations, chemicals, dust, etc).

Hyperbole. The engine management and other systems vital to operation of the car have to meet such specifications, but infotainment systems can be mounted in the passenger compartment side of the firewall and so don't need to withstand such environmental conditions.

Take a consumer hard drive, put it in a deep freeze and let it chill to -20C. Now take it out and plug it in your PC.

Is it gonna work? No? Well I guess the same hard drive won't work in a car that's been parked overnight in the winter.

And that's just the first test your hardware has to pass before it can be installed in a car. Next up, vibration testing...

about a year and a half ago


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