Hacker News Reader

Hacker News

Comment by jpm_sd | Hacker News Reader

Full thread

jpm_sd

(2007)

This is really clever! But it looks incredibly dangerous and probably emits an enormous amount of RF noise.

The article never says what "TEA" stands for:

https://en.wikipedia.org/wiki/TEA_laser

Tranversely Excited Atmospheric

View on HN

Thanks for looking it up!

Since I am more familiar with rockets than with lasers, my first association with 'TEA' was 'triethylaluminum' [0] which can be used to ignite rocket engines. See also [1].

Now that we know what to look for, it does state that but it is a few paragraphs (too far) into the text:

If I understand it right, TEA stands for Transverse Excitation at Atmospheric pressure.

Writing a name out in full when using it for the first time and denoting the abbreviation that will be used further in the text might be a good idea in general.

[0] https://en.wikipedia.org/wiki/Triethylaluminium

[1] https://en.wikipedia.org/wiki/Triethylborane#Rocket

Triethylaluminum was also my first thought, so my initial reaction was "wait, you're putting what in a homemade project?"

Asking for a friend, would such a thing disrupt the connection between his neighbor's phone and said neighbor's Bluetooth speaker when he puts it next to his fence in the garden?

A spark gap generator would probably work better for that, but jamming is illegal.

Yeah I told that friend, but he feels that constantly providing background music for your neighbor's lives should also be illegal. He's looking for a more secluded house as well.

> constantly providing background music for your neighbor's lives should also be illegal

In most areas, it is often illegal, violates an ordinance, or is considered a tort.

I think this is a spark gap device. That's how it pumps the atoms in the air. Of course it's a pretty complicated way to make a spark.

"It's my arc-welder, officer."

Could you reach over / through the fence and hit the bluetooth connection button? You could probably change the volume, music, or play something offensive then. When they take it back indoors of course.

Years ago an engineer friend of mine had an upstairs neighbor who would play the same radio station at high volumes for long periods of the day, often well into the wee hours. Pleas for change had no effect.

So my friend bought and built an FM transmitter kit. He put it in his apartment in the closest spot to the guy's stereo. And then he broadcast beautiful silence on that radio station's frequency. The neighbor tried other stations for a while, but it just wasn't the same.

I wonder if a Bluetooth version of that is possible.

Uh, no. Not legally, at least.

My friend's approach wasn't legal either, so I was more asking about the technical possibility. I know Bluetooth is supposed to be more secure, but I have to wonder if random consumer electronics gear like a speaker really takes that seriously.

In a past life I had borderline crazy downstairs neighbours. They would usually wake us up by screaming at one another but on this particular occasion the radio was blasting at a ridiculous level. I actually don't think they home and perhaps it was an alarm set on the radio which had turned it on.

Thankfully after about 30 minutes of my flatmate and I getting really pissed off (it was like in the same room loud, not just a minor annoyance) I remembered that I had an old car FM transmitter for an MP3 player, after borrowing the batteries from the TV remote, cycling through the stations I was overjoyed to discover that one of the stations was close enough to the radio frequency to blot out the station it was tuned to. The reason I think they weren't home is I turned it on and off a few times but they didn't attempt to turn the radio to another channel or anything like that. I went to sleep with it on.

Technically the FM transmitter was legal at that point but using it to deliberately block someone else's radio is almost definitely illegal.

LOL. Your "friend" might be better off with a bluetooth jammer.

Probably less noisy than a car engine with traditional ignition coil. Not to mention all the PCs with glass cases.

Oh, yes indeed. And to properly shield it costs an order of magnitude more than the laser itself.

Reply on news.ycombinator.com