87 thoughts on “HackIt: New uses for old CRT monitors

  1. Well, with enough of them, you could build an array of them, with some appropriately high-tech buttons and keyboards, and call it a movie set.

    You might be able to (carefully) salvage the power supply and use it for Hi-V applications like a jacob’s ladder or plasma globe… you might even be able to convert the tube itself, I’m not sure, I’ve never worked with one.

  2. I have a cool idea, but don’t know if it works, a X-ray machine :)

    CRTs are shielded, but produce some x-rays.

    Accordings to wikipedia, they are allowed to produce up to 0.5 mR/h at a distance of 5cm. A disagnostic x-ray requires about 1.4 mGy, which is about 100mR. So about 200 hours. Of course its not that
    simple: e.g. x-rays from CRTs are softer, modern CRT usually produce far less radiation than the limit, maybe its not enough to distinguish it from background radiation ….

    But maybe its enough to show the existence of the x-rays to expose a film (for many hours) sticked to the CRT (with some cardboard to shield the light).
    If that works: try to reproduce simple pattern cut out of lead foil, or paint patterns with the right input AV-input or oszi-input, and finally try to x-ray some small (thin?) stuff. :)))

    Older color CRT should work better, higher acceleration voltage is better (but DONT tweak it to produce more radiation).

  3. It would be very hard to do, but it is possible a CRT could be converted to a vector monitor. Perfect for playing Asteroids, perhaps under MAME.

    You would have to replace all the control circuits, probably with an FPGA and three ADCs (x/y/intensity).

  4. Insert a nano-board and make an all in one pc. Ive seen this done at a local shop. He took a 21 inch Cornerstone and inserted a nano-board along with hd, dvd-rom, etc. He then tweaked the powersupply so the pc and monitor were powered by the monitors power supply. A very cool looking idea. (Yes Mac has already done it. Mac is kinda like the Simpsons. Theve done everything!)

  5. Similiar, could be done with a CRT:

    I have a huge old Sony Trinitron commercial TV. The “commercial” implies that it has a huge metal frame around it, and accepts RCA input but with a weird BNC-like connection. Anyways, my brother in law wants me to put it on it’s back so the screen is facing up, and put a glass plate overtop of it, making it a coffee table. Play some cool abstract videos or visualizations and you’re done!

  6. I friend of mine is collecting old CRT monitors and televisions in order to make a small tesla coil. IM not sure the exact workings of it but if i understand it correctly he is using the transformer that puts a charge on the front of the glass. He will aqquire as many as he can and connect them in a serise and then use them too release one large high voltage low amperage charge. I will try to post a link to somre more information later if i get it.

  7. While in college I would go to thrift stores and purchase old green screen monitors. Apple Monitor iii (yes that’s 3) and even an early Mac. I’d then open them up, cut the wires leading to the deflection coils, and then wire them into either series or parallel (different monitors/axes worked better with one or the other) with the speakers to my stereo.

    So basically I made a very inaccurate oscilloscope.

    This produced analogue visualizations way before winamp or iTunes did the same. In fact, I wrote an iTunes pluggin a few years ago to simmulate the effect.

    I had a Led Zeppelin bootleg that at one point would actually draw a pretty clear guitar on the screen. Unfortunately the instrument being played at that moment was a harmonica, but it was cool.

    For those that are less adventurous, if you have an old monitor/tv with a composite (RCA) input you can simply plug in a speaker wire and you’ll get a banding pattern that throbs with the music.

    I had two monitors mounted about 12 feet high in my dorm room in college, one throbbing and one doing the oscilloscope thing. People would bring CDs buy to see what they looked like. Ben Harper was always impressive, as was Dark Side of the Moon.

  8. You can use a crt monitor as a HV psu capable of providing about 30 KV, very easy to do. All you have to do is open up the monitor, pull off the the lead with the suction cup connected to the back of the crt (+ voltage) and then use the chassis as ground. Its that easy and also very dangerous!

  9. I volunteer at the USS Midway Museum in San Diego, as a docent and in the Exhibits department. I’m restoring the Ship’s Inertial Navigation Room, and I installed an old CRT monitor in place of a broken CRT screen that displayed navigation information generated by the gyros and an old Univac 642B mainframe. I wrote a JavaScript-based web page that generates fictional navigation data based on the time of day, so now the formerly dead console looks like it’s actually operating.

  10. if they’re shallow enough, say 12″ deep, then line a load up and point them at a wall, still hooked into your usual outputs. levoila! Worlds largest ambilight – with extremely good colour reproduction.


    Use the shell as a bin.


    use the coffee table idea, but hijack the cable and send a slow cycle of white noise through each channel in turn.

  11. I’ve done the same thing John has. The quick and dirty way to do this is to find where the horizontal and vertical coils meet the mainboard and unplug them. plug the horizontal coil into the vertical plug. then attach an amplified audio signal to the vertical coil. it will produce a relatively slow (60Hz) line across the screen (very bright!! turn down the brightness!) and it will me modulated by the audio signal.

    keep in mind there are very very dangerous voltages present inside a crt. be careful!!

  12. Cover the screen with a sheet of aluminium foil and attach a wire to the foil with an alligator clip. Hold the bare end of the wire while you turn the monitor on and off.

    You get a fun shock!

  13. I have always wanted to take 307,200 monitors out into the desert, lay them on their backs and drive each one as a pixel (640×480). More resolution, more monitors.

    I figured on just sending a particular single color to each monitor, but if you really wanted to get fancy and had the horsepower, maybe you could do the photomosaic thing and send images instead.

    Since I have many big ideas and even more laziness, I think this is a job for someone else. Any takers?

  14. alex,

    Note: the following is potentially dangerous. crt screens can hold a big charge for a long time after being unplugged and can serious mess you up or even kill you. what follows does not contain any safety information so if you don’t know what you’re doing then don’t mess with this stuff.

    Steve’s description is pretty similar to what I used to do. While I did use the vertical scan signal at times to produce a more traditional waveform, I found that using one speaker to drive the horizontal and one to drive the vertical made more interesting patterns. basically I’d find the wires that go to the two coils at the back of the tube. If they could be unplugged I’d unplug them but sometimes I’d just cut them. I did this on probably 5 different montiors for various people and it was always a bit different.

    Anyhow, after cutting the two wires leading to a coil I’d then take a wire leading from my stereo to my speaker ($200 sharp all in one from a big box store, nothing nice) and wire the coil either in series or parallel with the speaker. Sometimes series would work better, sometimes parallel would. Then I’d do the same with the other speaker and the other coil. Again, each coil was different so I might do parallel on one and series on the other. Whatever produced the most deflection without going off the screen. I’d be playing music through it the whole time and turn it on occasionally to test.

    So in the end I’d have the left speaker doing vertical deflection and the right speaker doing horizontal. When sound was coming out of both speakers I’d get crazy spirograph type patterns. When sound was mostly out of one side or the other the patterns would be mostly horizontal or vertical. pink floyd would have lots of transitions from one to the other.

    The patterns were always very reactive to the music, unlike many visualizers in itunes or whatnot. more volume made for bigger patterns. bass made for big loops, higher tones for tighter loops.

    I should note that one monitor I did this to started smoking almost immediately. I assume this is because the power that should have been going from the sawtooth waveform generators to the coils for h and v scan was now not going anywhere. if I had been more sophisticated I’d have measured the resistance of the coils and put resistors on the wires coming out of the board to replace the coils.

    Again old Apple ][ and c=64 monitors always worked. I sent a friend a Mac classic modded to plug into his stereo for his birthday and he still has it and it still runs 10 years later.

    I am in the process of putting together a website that will host my software projects. I’ll include the iTunes pluggin that mimics the green screen effect and the winamp pluggin that I wrote if I can find it.

    Given that my current project combines wiimote head tracking with laser pointer detection for a fps game (I’ve got it all working but need to add polish like explosions) I’m thinking that you might be interested in posting a link to the site when it goes live in a few weeks.

  15. silic0re the lifter was way back!

    lelandwitter u buy the screens, cables, genorator and i’ll carry them and lay then out in the desert and pic the image to go on them. hmmm gotesex!! imagin the astronoughts throughing up in their spacesuites ROLF!!

    i hear all the ‘real’ rockstars drop them out of a penthouse window… now post that on utube and u’ll be famous ;D

  16. I want someone who knows about TV innards to make a howto for hooking RGB signals directly into the CRT driver circuit, bypassing the NTSC junk (like the SCART connector in Europe).

    Why? Because (most) game systems output RGB, but with a 15KHz horiz sync that VGA monitors can’t use. Since analog TV’s will be pretty much useless by next year (converter box? puh-lease…) they might as well be converted into (relatively) high quality videogame monitors.

  17. I did what #19 said with a big screen TV after experimenting with a CRT once. I would definitely say be careful with larger displays. I’ve never been tasered before but I probably got a similar sensation lol. You can get some pretty big arcs too with a grounded aluminum can.

  18. In keeping with this idea maybe some projects using old televisions would be good as well.

    the digital broadcast switchover means that there will be some good trash pickings coming up very soon in the way of functional television sets thrown out by the rich and the ignorant.
    (ghod bless ‘em)

    of course you should be careful.

    don’t want some damn fool zapping themselves with a flyback.

    …or do we?

  19. CRTs can be made into left-right-reversing mirror image displays with ease: All you have to do is reverse the polarity on the horizontal steering coil. The equivalent modification on an LCD monitor requires special DSP hardware or software, I’m pretty sure.

    So why would you want a left-right-reversing mirror image display? So you could reflect the image off a mirror, of course, and still have it legible. Why would you want to do that? Well, perhaps to make a teleprompter, or to make a video chat display that puts the camera right behind the apparent screen so that the communicating parties can look directly at the screen and at the camera at the same time.

  20. A project that I’ve wanted to do for a long time now is the ‘All-in-One’ PC using a CRT monitor casing. Removing the actual tube and replacing it with the LCD screen from TFT. Motherboard, drives, PSU etc could then all be mounted internal to the CRT case.

    I have to admit, some of the CRT cases I’ve seen have looked really nice (mainly the black and silver).

    Alternatively, from the new CRT monitors I’ve had open, there is usually a bit of free space. How about mounting a mini-itx or nano-itx board in the CRT casing?

  21. #1Show bright white on the screen, put a metal ring around the front with some mesh inside, (so you can see white if you look straight at it). Hang it up high, outside, and night, in the summer time, and attract bugs. then do some basic high voltage hack on the metal ring and screen material so the bugs get zapped.

    #2 Use the ultra-high pitched sound those things put off to be like a dog whistle, to call your dogs in for dinner, or to do some kind of dog behavior adjustment. I’m sure they can hear that sound perfectly clear, so you could train them to do stuff based on when they hear the sound. You could wire the AC into a solid state relay (or just hook it up to a DPMS screen saver) to make a computer turn the sound on and off (if say you want your dog to come back inside every night at 7pm)

  22. You could tie a solar panel straight against the screen, and have a program that controls an analog voltage based on the color it displays. You could probably regulate voltage in a very precise way doing that. The frequency would be relatively low compared to even a sound card, but it might be useful for some crazy hack.

  23. Sean:
    Ever used that idea as a prank? If somebody doesn’t have the software to flip the screen (like nvidia/intel drivers can do) they will be in trouble, and its simple to pull off.

    mike: You can just use a CFL to attract them + 120v grill to fry em’. You don’t need anything more than that, definitely not the many kV inside a monitor. It would be fun I must admit, but such a waste of power.

    Quite a few people have mentioned arrays. Is there a way to make an array out of NTSC tv signals? I only have small tvs, and a 2×2 grid of tvs would be awesome :D

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