Quote: Original post by owl
Of course, sitting with your ear against his door while his having sex with his girlfriend is a way more... ehm, fullfilling?

I just threw up in my mouth a little [sick]. And I'm not too scared about when he finds out it was me. Heck, tomorrow morning I'm going to move them into more audible spots. He's not getting annoyed enough :) I mean, we live on the Engineering Floor here at the U. I'm kind of depressed I'm the first one to actually do any kind of pranking.

@Sneftel: That fits me to an almost scary level. Just a couple days ago I was seriously considering buying 50,000 forks so I could fork my friend's house... I'm glad I decided to wait a day and think about it.

Certainly not as expensive as buying enough rolls of tape to suspend your 190 lb. friend on the ceiling.

Let me tell you, that's a shitload of tape.

Quote: Original post by Zipster
Certainly not as expensive as buying enough rolls of tape to suspend your 190 lb. friend on the ceiling.

Let me tell you, that's a shitload of tape.

Please tell me you have pictures...

Quote: Original post by MikeTacular

Quote: Original post by Zipster
Certainly not as expensive as buying enough rolls of tape to suspend your 190 lb. friend on the ceiling.

Let me tell you, that's a shitload of tape.

Please tell me you have pictures...

yes, pretty please.

I think you greatly overestimate effect of that things. Dunno about ya but I'd get used to it rather quickly even with random timing.

Though I know how to locate source with pc. I only need to connect 2 microphones at specific distance to pc and leave it recording in stereo, then move microphones for several beeps. Each trial confines possible source locations to hyperboloid.

Quote: Original post by Dmytry
Though I know how to locate source with pc. I only need to connect 2 microphones at specific distance to pc and leave it recording in stereo, then move microphones for several beeps. Each trial confines possible source locations to hyperboloid.

Not all of us are fortunate enough to live in an anechoic chamber.

Quote: Original post by Sneftel

Quote: Original post by Dmytry
Though I know how to locate source with pc. I only need to connect 2 microphones at specific distance to pc and leave it recording in stereo, then move microphones for several beeps. Each trial confines possible source locations to hyperboloid.

Not all of us are fortunate enough to live in an anechoic chamber.

not all of us are unfortunate enough to not have... ok I wont say it, would be rude.
What problem, exactly, would echoes cause? The sound that did travel line-of-sight shortest distance arrives first, anyhow, so start of the beep is anyhow unaffected by echoes and interference.

Now, plotting the hyperboloid. That's extremely high tech. Attach ends of regular sewing thread to microphones, tie a knot on it so that distance difference from knot to microphones is equal to measured distance difference, then maintain the difference by folding excess thread in two from that knot and winding it onto spool. Very simple, you don't even need to know word "hyperboloid".

Quote: Original post by Dmytry
What problem, exactly, would echoes cause? The sound that did travel line-of-sight shortest distance arrives first, anyhow, so start of the beep is anyhow unaffected by echoes and interference.

Ideally, if the sound source is floating in the air. If it's right by a wall, however (EDIT: or, of course, behind an object), diffusion will cause even the beginning of the wave to be difficult to pinpoint in time, and make it considerably positionally dependent. Additionally, depending on how the beeper circuit is constructed, the noise may ramp up over a few cycles, making the correspondence between the waveforms further ambiguous. It's not a worthless method, of course... even with all that noise in the system, the error would probably be within a foot or so. Seems a little elaborate compared to just listening for where it came from, though. Never underestimate the power of the outer ear.

Quote: Original post by Sneftel

Quote: Original post by Dmytry
What problem, exactly, would echoes cause? The sound that did travel line-of-sight shortest distance arrives first, anyhow, so start of the beep is anyhow unaffected by echoes and interference.

Ideally, if the sound source is floating in the air. If it's right by a wall, however

what then? How a wall will muddle arrival time of front of pulse?

Quote:
(EDIT: or, of course, behind an object), diffusion will cause even the beginning of the wave to be difficult to pinpoint in time

one is inside light fixture, other inside wall socket. Of course, the accuracy will be limited to size of opening of light fixture, and of course you may need to reposition microphone if you find that beginning of beep is not sharp.
You could make a case if sound were to get from air into wall (where speed of sound is higher) and then from wall to air, arriving quicker than line-of-sight. At such frequency, that is negligible.

Quote:
Seems a little elaborate compared to just listening for where it came from, though. Never underestimate the power of the outer ear.

one little detail: victim did not find it by ear... why, of course, because it is hard to locate 12khz sound source that beeps shortly once every few minutes, especially when there are two sources and you suspect one.
Ever been outside, heard grasshoppers? Those are far easier case: no flat surfaces nearby, kind of chirp modulated sound, *made* for position detection (by other grasshoppers), regular rather short interval.

Quote: Original post by MikeTacular
So far things are going well. I heard him and his girlfriend talking in his room. He asked her "What the hell is that ringing sound?" to which she replied "I don't know but I've been hearing it every once in a while," and he said "Yeah, I keep looking for it but I don't know what it is." [grin]

I'm hoping that the annoyingness builds up over time and he just freaks out eventually. If he doesn't start giving better reactions in the next couple of days I'm going to move them into more audible locations and hope that helps.

As far as sabotaging his stereo or competing with a bigger, better stereo... where's the fun in that? I want to watch him suffer. All in good fun, of course.

Go to a hardware store, you may need to find a larger supplier, mom-and pop stores may not carry it. Look around for the following item (Or items to build one from):

Warehouse Door Bell: One that runs on standard household current and is designed to be plugged into a light socket.

These things do exist, they are a large bell of some sort, and are designed to be heard over machines and such. The point of them was they could quickly be wired into place with conduit and a standard light switch and fixture.


How is this useful as a prank? Works best in winter when it gets dark sooner. Wait till you know the person is going out to party and consuming alcohol. Sneak into their room, and replace their light bulb with one and unscrew all other light bulbs on that switch. Expect to be woken up by a loud ringing, but expect your target to require new pants in the process.

One of my profs admits to having used this prank on several occasions.