Generate AM Radio Broadcasts With Your Monitor

tessellation writes: "Tempest for Eliza is a program that uses your computer monitor to send out AM radio signals. You can then hear computer generated music in your radio." Here is your big chance to disrupt free thinking radio programs in your neighborhood.

Comments

Done it...

[Kymermosst]

It really worked... it took more work than the instructions portrayed to get it working, but it's pretty nifty.

Can't do MP3s yet... at least, not the version I tried.

first post?

Re:Done it...

[Kymermosst]

With a crappy radio, it had to be fairly close 5 feet to make it out... my monitor doesn't put out that much rf... it's a low-rad type.

Now, putting my ham radio at 5 watts about 10 feet away does interesting things to my monitor, I can tell you that!

weird, its not working

[ddent]

I wonder if it has something to do with how thin my monitor is... now wait a second, does this work on LCDs? :) Oh, maybe thats why...

stream mp3s?

[stonecoldt]

.ogg files would sound so much better out of that AM radio. :-P

This isn't the first

[recursiv]

This isn't the first time something like this has appeared on slashdot. Way back in the day ('99) there was an article about a guy who was using the radio interference from his motherboard to do the same sort of thing.

Re:This isn't the first

[b1t r0t]

Way back in the real "way back in the day", around 1980 or 1981 or so, before the FCC got into the act, I was using the RFI from my TRS-80 to generate music. The cool part was that any code to generate sound out the cassette port was sufficient to have the sound show up on an AM radio via RFI.

Back in ancient times

[ynotds]

This is really testing my memory, but I think it was after we upgraded from our IBM 1440 to an early System/360 that our operators discovered they could tune an AM radio to a certain frequency and thereby listen to the puter.

Maybe somebody with a better memory might know a few more details.

Re:Back in ancient times

[Florian Weimer]

Our local computer museum has got a PDP-8 which can broadcast polyphonic music using its main CPU, running a specially crafted sequences of instructions. Actually, operators used the AM radio effect to monitor the machine activity. With some experience, you can here if the CPU is idle or spinning in some kind of endless loop. If you are familiar with a longer job, you can guess which part is currently running, and estimate the remaining time.

At home, my computer has a similar feature: if the CPU is loaded, the sound of the fans changes, so I can tell if the computing-intense job is still running or not.

this reminds me...

[anotherone]

This reminds me of a game I used to have for my TI-82. As I recall it was a dumb game, but it was the first (and as far as I know, the only) calculator game with music.

I think it worked by twiggling the link port's connection really fast or something, but if you held it near an untuned radio, it'd play really poor music. Really, really bad music. But, hey; what do you expect from a damn calculator?

Anyway, this is one of those completly useless, yet incredibly cool things that I like to see. Very neat.

Re:this reminds me...

[FuegoFuerte]

Actually, quite a few of the games for the TI-86 have music. Mario does, and I believe Tetris does also. (at least the versions I had). I've since gone to the TI-92+, and haven't tried it with that. On the 86, I heard rumors that you could tune it with an AM radio, but you could also plug headphones straight into the data port (with an adapter to go from the 2mm to the 3mm plug) and hear the sound great. Someone actually wrote a program to play music that way, though you can't fit much music into the memory on the 86. Pretty crappy quality too. You can probably still find the programs and info on ticalc.org or somewhere. It's been a couple years, so I don't remember where I first found out about it.

Eliza?

[the Atomic Rabbit]

Huh? Does the program use your monitor to produce a radio program about psychotherapy? How do you describe your problems to it?

Re:Eliza?

[x136]

]Hello Eliza.
Hello.
]I don't feel very good.
Why is it that you don't feel very good?
]Well, my monitor is talking to my radio.
Are you concerned about your monitor talking to your radio?
]Well, yes. It's not supposed to work that way.
Why isn't it supposed to work that way?
]Shut up Eliza.
Why do you want me to shut up?
]Because you are a stupid worthless computer program.
I sense much anger in you. Perhaps you should seek medical help.
]Oh, what do you know?
What is it about what I know that interests you?
]ARRRRRRGGGHHH!!!
I don't understand what you mean by ARRRRRRGGGHHH!!!. Please try again.
]quit
OK. Goodbye.
]

Van Eck phreaking

[jasonzzz]

For many years during the cold war, the NSA had
been nervous about natural radiations emanating/broadcasted by VDTs and electrical wiring. So much so that many government sites were constructed with TEMPEST safeguards with thick concrete walls, wiremesh shielding and isolated electrical works. Even then, VDTs, type writers, phones, and other electrical devices were never placed close to walls adjacent to the outside of the enclosed space.

Read the Van Eck document.
http://www.shmoo.com/tempest/emr.pdf

Read the TEMPEST page
http://www.eskimo.com/~joelm/tempest.html

kernel?

[ameoba]

Considering that the 2.5 kernel development cycle hasn't begun yet, is there still time to get the Monitro Sound device driver put in?

subliminal messages

[elizard2k]

This is your chance to send out the many subliminal messages to the poor listeners at your work/neighborhood. *snicker*

*crackle* this program has been interrupted by your next door geek .. buy him computer parts *crackle*

for the lazy

[swagr]

Put an AM tuner near your box, and you'll easily find a frequency (many in fact) that let you hear your PC.

Type some keys... move your mouse, open a window...

Not only are you broadcasting... you're composing...

A better way to tell the eavesdropping feds...

[i22y]

"All your base are belong to us!"

Re:Weird.

[Andux]

it could be your own personal radio station

Great. We could piss off the RIAA and the FCC, all at once.

Seriously, though, I doubt you could get a strong enough signal out of it for a decent broadcast (and if you can, you're probably glowing in the dark already). You'd be better off just bolting a big chunk of metal to the roof and doing things the old-fashioned way.

FWIW

[adolf]

While the instructions say to use a shortwave radio tuned to 10MHz, I found that a regular broadcast-band AM radio worked fine. Just chop a zero off of the frequency, and tune in somewhere around 1000. (1030 was what my tuner said, at the point where the "music" was most plainly heard).

Spooky stuff, this.

Can this be used for transmitting voice?

[dhanav]

Code a picture that will produce a voice and we have an encrypted speech. Sounds interesting. I am going to display all those pics in my collection and listen for hidden messages :).

The Fabulous Altair Connection

[foqn1bo]

I recall hearing something once about the homebrew computer club @ Cal back in the 70's doing something like this using an Altair and a radio to play The Beatles' classic, "Fool on the Hill". It was judged the most interesting and useful thing anyone had managed to do with an Altair yet. I am glad that over 20 years later programmers are dedicated to making our computers just as useful and practical.

Why it's called Eliza

[dido]

Well, it didn't immediately click because the Beethoven song he used to test the program is better known by its German name: "Für Elise" (well, that's what the book of piano pieces I used to have calls that tune). Trouble is, everyone's associations to the name 'Eliza' is the 'AI' program by Joseph Weizenbaum...

All your funny are belong to six months ago!

[ebbomega]

Someone set up us the dead horse!

Re:Privacy Issues?

[Graymalkin]

that's called van Eck phreaking and has been around for a while now. With a sophisticated enough antenna array you can get basically a screen dump from someone's CRT monitor. With even better equipment and the right processing you can monitor closed circuit signals just by listening to the EMR they give off when current in run through them. Radioshack has the parts to build a toy that can tap a telephone line without splicing wire or having access to cables or trunks.

Old News... My TRS-80 does this already :)

[Chmarr]

Eh... old news. My TRS-80 Model I had a game who's instructions read:

For sound effects, place an AM radio next to your monitor

It was a car racing game... the sound effects made a kind of sense... except they didnt stop when you crashed the car :)

Re:weird, its not working - but it does! :))

[leibnitz27]

But I've been in one of Ross Andersons lectures where him and Markus demonstrated tempest working against a laptop. Just using LCD won't protect you, see Here (google cache - page seems to be missing) and Here

Good description of van Eck

[English Guy]

Good description of van Eck phreaking in Cryptonomicon by Neal Stephenson or in this article (which is quite a large pdf)

Sweetcode had ya beat!

[TheLocustNMI]

SweetCode had you beat on this one! It's a great little site. Imagine, if you will, Freshmeat with all the chaff removed.

harumph. Another Johnny-Come-Lately

[hawk]

While remembering the 8bits and their tricks is impressive, it was hardly new. This was done on IBM's and others at least in the 60's, and possibly the late 50's.

Additionally, line printerss played Jingle Bells . . .

hawk

Re:harumph. Another Johnny-Come-Lately

[dattaway]

This was done on IBM's and others at least in the 60's, and possibly the late 50's.

This still won't stop some talented individual who is handy with patent applications from filing today. Be warned...

Re:Legal issues

[dattaway]

Oh, there are a few ways to increase the output of your monitor by many watts too. These require the case to be taken off and willingness to turn your screwdriver on parts connected to the B+ chassis (about 2000 volts.) Uplugging the computer during this process is optional. Voiding your monitor's warranty and making it a potential fire hazard is your destiny with this procedure.

Brightness is one good way. Want to vaporize some phosphor off the screen? Well, look at that funny transformer with the thick red wire going to the picture tube's top. No, don't put your fingers under that red cap as you'll discharge 30,000 volts. The capacitance stores enough current that it may jump start your heart into transporter mode to a higher (or lower) place in the heavens. Anyways, look back on the transformer where one or two or more small screwdriver adjustments are provided. One should be the focusing voltage for the electron voltage. All this adjustment will do is make your picture tube require prescription glasses when things get fuzzy. The other adjustment dangerously raises the drive voltages of your homebrew particle accelerator into x-ray producing levels. Enjoy.

The other tasty method to injure personal health is to max out horizontal drive voltage. Your adjustment of choice is on the main circuit board that is a minefield of tempting adjustments. The one I am talking about is an adjustable inductor, when tinkered with will lose the monitor's calibration for the horizontal picture width. Its the one adjustable inductor that stands taller than the rest and its frequency is so high, its design require the turns of wire to be a bundle of stranded wire. Yes, remove the powdered ferrite slug out of this coil. Current will now saturate the picture tube's yoke coils. Electronic devices and radios around the house will now bow to your monitor's new elite status.

There you go. Not only have you voided your monitor's warranty, you have just demonstrated why picture tubes are evil particle accelerators. They should be banned.