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Making Music with CPU Activity
Tails writes "Ever wonder how you could make that useless radio interference your CPU generates into interesting noise? Forcing operations on his CPU and Memory bus, Berke Durak has made a tunable FM signal out of the radio activity his motherboard creates.. " Didn't we see this stuff in Triumph of the Nerds? Looks nifty tho.
I'd rather *stop* the interference that my computer generates. I want the scrolling of the video to not affect either my sound card or my FM radio.
and the geeky things we do. I love it!
I remember people doing this on their TRS 80 in the 80s with a radio nearby.
The article includes 8080 assembly source and machine code for the program (all 33 bytes of it), a table of three octaves of notes and the data used for the songs at the recital.
Oh, yeah. My grandfather used to have huge song sequences recorded for that old thing. After eight or nine tape misfires, we could *sometimes* get it loaded. Remember Lemonade Loaders for the TRS-80 series? That was grandpappy. -lev
Well, my Sony Trinitron moniter has engravedon the back of it the followin text:
Note the use of the word "harmful" in condition 1. I guess radio transmisions aren't considered harmful. Is anyone else bothered by that second condition though? That "undesired operation" bit always bugged me.I saw it done on tv using a blue box called and Altairs 8800, I think. It broadcast a neat little song over an AM transitor radio. Interesting! Chessucat
I don't get it. What's the point? Why doesn't this guy use the extra CPU cycles of his brain to do something productive?
if nothing is allowed to make inteference, why bother saying that it has to take interference? shouldn't there not be any? -another totally incoherent message from an anonymous coward
This was done at close range with a Sony walkman. Since the signal diminishes as you move away from the source (by the square of the distance) your CPU probably wouldn't be heard on your neighbors stereo. Anybody know the sensitivity of a Sony walkman?
The frequency at which my Sony Multiscan monitor is driven by linux by default (67 Hz, I think) produces a constant tone on 890 AM.
A friend and I created music with an IBM 1620 in the late 60's (1968-69). By moving data from area of memory to another you culd generate different frequencies of static on an AM radio nearby. Victor even got an imitation henrix playing the Star-Spangled Banner.
My guess is that the controller ribbon could be lengthened and used outside the case as an antenae. Maybe once we isolate a strong signal source we could use the power cord and electrical wiring to transfer the signal to other parts of the house. This LAN idea could work. Sure hope those N acronym people don't figure this out.
I too remember listening to a Linc-8 play music in our neuroscience lab around 1967.
Oooohhh... that's cool! As much fun as the speech synthesizer that worked by cycling the TRS-80 Model I's cassette relay switch -- audible, kind of understandable and pretty dang kewl for 1980....
So how would one go about generating some coherent AM noise from a typical PC?
C64 1451 (or was it 1541) disk drives generated enough FM interferecnce, you could tell whenever there was disk activity (It was strong enough, I'd almost bet you'd be able demodulate into something useful...). And this was from 6 ft. away! ;-)
Thanks, I had the same thing happening to me (except for me it was quite annoying... ;-). Now I know I'm not insane (I had even disconnected the PC speaker to be sure!). :-)
In 1982, I wrote a 6502 program on an Apple 2+ that read the cassette input and decoded the audio frequencies from an old drum-style Xerox fax machine to make a crude 16-level grey-scale scanner. By using an oscillator to produce grey bands on the fax machine, I calibrated the fax machine output to the shade of black. While writing the code, I mistakenly addressed an unused address rather than the cassette port, and got 60-Hz noise. I wrote a 60-Hz time domain filter to get rid of that noise before I realized that I wasn't getting the right signal at all. So, in theory, a computer could be used to decode a message surreptitiously transmitted from an adjacent computer using wireless transmission and no extra hardware. Anyone game to try?
CRTs aren't so hard. If I remember correctly, the NTSC line rate is about 15 kHz. That's a high pitched whine. What makes CRTs hard is when even a little of your hearing is damaged. The top end is usually the first to go, and 15 kHz is real close. Anyone who is a young child/woman/asthmatic is likely to have a higher range of hearing (Just for interests sake...).
;-)
What's drives me nuts is the 60 Hz (or Elsewhere, 50 Hz) buzz badly sheilded audio stuff emits on speakers, or (slightly) broken transformers and fluorescent light ballasts. Most old (but not ainchent) buildings make me wanna go out of my mind.
I've encountered several machines on which hard disk and other activity causes noise through the speakers. Muting the CD audio input usually kills, or at least reduces, this noise.
This is nothing new. We used to leave an AM transistor radio on top of the IBM 1620 and listen to the "tunes"... No need to tell you how long ago that was.
I seem to recall reading (perhaps in S. Levy's Hackers?) about the old IBM 704 Vacuum Tube-based systems where one could play music on the tubes. Apparently the large amounts of current flowing through the tube bays caused Electromagnetic induction in the chassis, causing it to "sing" and "hum" as different processor instructions were passed through them. They took the panels off of the monster cabinets to make them more audible. Then there's Printer music!! There was a program I saw once that played "She's coming 'round the mountain" on an ancient line-at-a-time printer. Depending on what characters and what number of chars were printed, you ended up with different pitches. In one part, supposedly where you stomp if you're singing it, it would throw all the character hammers at once, often blowing the fuse!
It's called TEMPEST monitoring. By my understanding, every monitor broadcasts on a slightley different frequency, so the signal really can't be jammed. The only way to avoid TEMPEST is through LOTS of shielding.
Back in the 80's.. i had an MSX 2 homecomputer (of wich most americans propably know nothing about) MSx was a Z80 based system, with memory mapper, hardware video-accel (what the PC called "windows accelerator), diskdrives.. etc.. it came in several configurations froma multitude of vendors (some 20 different manufacturers) My model (the Philips NMS8280) had a video-digitizer in it, and sound-mixing capabilities. When i put the sound-mixing slider on the front of the machine _just_ under it's full setting, i would be able to tune into non-used channel on my FM-radio.. and hear the sound of the MSX.. playing Tetris.. or anything else. I discovered this when i was driving with my father in his car, and we pulled up to the parking lot near our house, and we heard the music of my brother player Columns on the MSX.. on the car-radio.. Go figure..
You can also produce different pitched sounds by moving the head of a floppy drive at different speeds. There was a virus for ( it's name was Gaddafi ) for AmigaOS that would occasionaly play "El Condor Pasa" with the internal 3,5" floppy ! The coolest virus ever :-)
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My dad's workplace used to have a mini (couldn't identify the type... I was very young at the time) that would play the Star-Spangled Banner on the AM band when it was shut down for the night. I think it was the same one where its only response to any kind of syntax error was "EH?", on the theory that, 90% of the time, you'd know what you did wrong without being told...
The discussion in the messages had very little to do with music from system noise.
The topic under discussion was software that secretly transmits information by taking advantage of the radio emissions.
The music angle is a simple diversion/nostalgia trip, think security!
Alas, playing music is indeed an old hack. I remember listening to Christmas songs on an AM radio sitting on the console of an RCA 301 in 1965.
I was just cleaning out the garage and in a box of old stuff, I found my 1966 offer letter from Control Data. I left RCA and joined them on 6-6-66 at the grand salary of $505 a MONTH.
That was after my first real hack: A friend and I managed to program a 301 in machine code so that we could scroll messages across its memory display lights. We put the program in a test station 301 at RCA with the message "Call John at 555-1212" running - it was the phone number of the CDC recruiter!
DC Stultz
In 1980 (yeah, carbon date this, buddy), I was working at a UN boondoggle in Austria called the International Institute for Applied Systems Analysis. There I saw two very interesting minicomputers, one was a Czechoslovakian copy of a PDP-11, and the other was an original Hungarian design called a TPA-70. This charming machine had a volume and tone control on the front panel. I cannot remember if it was an AM radio receiver or a 1-bit hack making the sound, but I think it was AM noise from the memory. I still have the manuals somewhere in a box in an attic...
I wrote parts of this stuff
I seem to remember reading an article a while back about the new high-frequency SVGA monitors.. and how with the appropriate receiver, the signal could actually be mirrored via radio waves as far as 150 feet away.... through walls and what not. it all depended on how many monitors were in the vicinity and broadcasting noise on the different frequencies....
Proof that a system is still insecure, no matter how much you do to it.
Of course, I guess a large issue, is what exactly is all the EMF doing to our bodies? The normal level of background EMF is much lower than what we currently bombard ourselves with from all directions.... oddly enough, I know people who think that microwave radio transmitters ony transmit from the transmitter straight to the little dish.... there's no overage.. no.. none at all... and if you move the dish.. I guess the transmitter is smart enough to move the signal....
Reeses
-- Give him Head? Be a Beacon?
-- Give him Head? Be a Beacon? :P)
(If you can't figure out how to E-Mail me, Don't.
Anyone remember Dancing Demon for the TRS-80 model 1?
Don't you mean Root Boy Slim???
CUR ALLOC 20195.....5804M
Or at least with my old p90 I could. Whenever my computer was doing something processor/memory intensive, I could hear it making a strange sound.
I can also hear my video card making a sound when things are drawing to video memory. Actually, maybe it's the bus that makes the sound.
I can also hear things like CRTs scanning. I always know which TVs in the house are on.
It was probably the bypass capacitors for the RAM. DRAMs produce large current spikes when they are accessed and capacitors can behave like electrostatic speakers.
Mea navis aericumbens anguillis abundat
i'd try it myself but i'm on a mac and i doubt this is the kind of thing that would work on all versions of linux. maybe later i'll reboot into linuxppc, download it and see if it compiles.. but even so i doubt a 75 mhz machine will reach up into the FM band, although the CRT version might work.
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anyway, this might be a great source of random audio for the one-time-pad security thing mentioned in the other article today. put an FM radio in the audio-in jack and run SETI@home or something complex to ensure the sound coming out the CPU will be random and unreproducable. Or run RC5, just for the sheer irony value of cracking one type of encryption and generating another in the process. If OTP were actually something useful, that would be a great idea.. -_-
<ramble>
Irritable, left-wing and possibly humorous bumper stickers and t-shirts
Yeah, my dad and I did that on ours like 15 or 20 years ago.
...with a Beowulf cluster!
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As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
If you get a pair of cheap computer speakers you can do this too. I remember my Soundblaster 16 making noise when my video display had a large write to it, and when I read from my sbpcd. Anyway, isn't this a violation of FCC regulations? I thought it was, in the part about this device may not make any interference, and must accept all incoming interference?
Indeed, this is an old, old trick...and why it gets attention here is beyond me.
:)
There's even a name for it. "The Voice of God" trick... I've used this technique to determine if hardware is working when you have absolutely no other way of determining the health of a system. For example, I picked up an SGI Indigo 2 at a surplus auction a while back.. didnt have a keyboard, a monitor, or a mouse to plug into it. I basically had a power light, and thats it. Putting an AM radio in close proximity to the motherboard and tuning it to a clear frequency will result in your being able hear the motherboard go through its self check. If you hear nothing, the board is dead. If you hear alot of chatter happening on the bus, you can be fairly certain the machine is at least salvagable.
Now, if this guy were to have actually written code to play -music- by running data through his mobo at different rates, that would be different. Until then, i'll sit back and wait for someone to top the ultimate trick:
Make a Commodore 64 play "A Bicycle Built For Two" by grinding the stepper motor back and forth on the read/write head of a 1541 disk drive. Saw this done back in 1987.
Bowie J. Poag
Bowie J. Poag
Making it be done on FM is magic.
Not really. The limited edition of the 2.2.10 kernel that was given away with Kellogg's Cornflakes had a special frequency modulation module; it works best when combined with Kellogg's proprietary 'snap crackle pop' sound card. It's only got three channels, and the second one sounds like an old LP, but it's still very effective. The entire musical output of Fatboy Slim can be generated overnight and released as MP3s when you get up in the morning.
And here I thought I was the only one on /. old enough to remember Dompier. :)
I had an Imsai, not an Altair, and remember too well loading some simple programs from the front panel switches. (Let the kids try to figure out what that means.)
And then there was the ASR-33..........
--- Bill
My first exposure to computers was on a high school field trip to the old DEC factory in Maynard MA (in an old textile mill) where they were making early minicomputers - PDP 8's with 12 bit words, Link 8's etc. in 1967. During this trip we were shown a Link 8 with an AM radio sitting on top of the machine playing Greensleeves based on the program running in the machine at the time. This trick is at least 35 years old.
Could we make an mp3 "broadcaster" out of this? :) That would make an interesting output plugin for Winamp or Xmms.
It seems to me that it would prove useful to investigate the use of this ability to generate coherent signals from a processor as a method of connecting wireless devices. Your Jini laptop could use the processor as a resource and interact as it wished with other Jini. Phone lines could be identified electronically by the phone company, detectable by any technician or competent person with access to tools.
Perhaps such things will come about. I remember reading an article once about networks of processors with switchable gates that could adapt to their surroundings; as I remember, they communicated through electromagnetic signals - interference, perhaps. Very strange; when they moved the processors, they stopped working. Ah, it was in Discover magazine [...] at one point; I'd recommend reading it with this information in mind; a room could be wired with a network of low-power sensors, for instance.
Cool.
Making a system play music on an AM radio is a 30-year-old trick. Making it be done on FM is magic.
I can't seem to hear anything from my system. Maybe the shielding is good....I'll probably take the case off later....
What goes around, comes around.
99 little bugs in the code, 99 bugs in the code,
fix one bug, compile it again...
I'm a leaf on the wind. Watch how I soar.
Quite a few years back we where working on a Video on Demand system which had a Pentium 90 and 128 MB of RAM.
;)
We developed the software under DOS because the MPEG decoder only had closed source DOS drivers.
I had written the memory access routines because no DOS extenders supported >64MB.
Then when I started to run tests to verify my routines, the system started to make these funny chirping sounds. It wasn't loud but definately audible. And there where different tones. I was actually thinking of making the test routine a song, but since the whole project lasted only two months there was no time to play...
We have never been able to positively identify where the sound came from exactly, but we are pretty sure it was the RAM. It was not the power supply and there was no harddrive in the system.
When a few years later we had a custom motherboard made we told the manufacturer of this board and they just laughed at us, said it was impossible. Ah well, maybe one day I'll put that system together again...
Breace
mwahaha...
I wonder, then, what error msgs in Windows sound like when broadcast.. or those infamous Blue Screens of Death.
hmmmmm..
Insert mind here.
Who needs anything else?
/dev/urandom going at the same time, and you'll have an endless multimedia experience AT LEAST on par with CBS.
An unlimited amount of free music, much of it better than some junk on the radio today.
Get a simple cat
Vaguely related...
There were a number of programs on the Apple ][ and C-64 which played music by stepping the drive heads at various frequencies.
I had one that played In the Hall of the Mountain King which got more and more insane as it went. Kind of a test to see what level of abuse you'd let your drive go through.
I was used to realigning those damned 1541s anyway.
This shows why it is important to keep the lid on computercases. Computers are a big source of radio frequency interference and make the life of radio operators difficult.
Please put the lid on your computer if it isn't allready there.
All we are discussing here is what the military refers to as TEMPEST hazards. Your computer system (particularly the monitor) broadcasts signals in the radio frequency which, given the correct equipment, can be intercepted and interpreted intelligently. We used to have an $18000 286 System when I was in military communications - the only reason it was so expensive (a regular 286 was only $2200 or so) was because the whole thing was lined with lead to prevent TEMPEST emmissions. Like it or not your use of the computer can be monitored completely by someone sitting outside your house or apartment with a directional antenna and the correct equipment in a van.
Now the fact that someone is affecting their emmissions to play music is another matter that is quite cool. I remember a little program that someone wrote that would play "El Condor Pasa" on my Amiga's floppy drive.
"The first time I got drunk, I got married. The second time I bought a chimpanzee, after that I stayed sober" Arian Seid