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waterfall printer

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by kagan09, Dec 17, 2010.

  1. Sceadwian

    Sceadwian Banned

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    The minimum vertical dot height is going to be directly tied to the speed the solenoid can be reliably actuated at, if you want a longer display simply adding height is all that's needed. 5 or 10 wide would be a good start. 10 would give you some possibility of simple graphics, something like the swords or tear drops.
     
  2. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Perhaps look for some standard issue automotive fuel injector solenoids and then modify their spray nozzles by grinding or drilling them out so they squirt out a stream. Around here junkyards will sell them for a buck or two each at most.

    By controlling the input pressure you will change the output from drops to a steady stream. The rest would just be timing.
     
  3. Sceadwian

    Sceadwian Banned

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    Aren't fuel injectors solenoid driven cavities with air inlets? Simply drilling the hole's bigger won't help, they're designed to deliver small pulses of fluid. Even though that's apparent result from the video the truth is all that's being done is a natural release of native free flowing water pressure at atmospheric pressures. (read very low not high like a fuel injector) With a true solenoid you can turn the flow on and off so you can control the actual 'beam' length.

    I am however highly curious about the physical construction of a typical fuel injector, it could work.
     
    Last edited: Dec 18, 2010
  4. dave

    Dave New Member

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  5. nickelflippr

    nickelflippr Member

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    Very interesting project. Those micro/miniature valves are expensive. Here is a quick link that seems to indicate a drop rate of 30HZ is possible. A solenoid could pinch a flexible tube, like a short piece of surgical tubing, if that hasn't been mentioned already.

    Some cheap solenoid links:
    Ledex Miniature 12VDC Tubular Solenoid-The Electronic Goldmine
    Solenoids-The Electronic Goldmine
    12VDC 120mA Solenoid | Alltronics
     
  6. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    The few I have ever dissected where basic spring loaded needle valves with a fine spray nozzle on the end but there could be other versions I suspect.

    I will see if I have any more old ones around and if so I will take a picture of one disassembled if I can. They are really simple in design.

    The main reason I mentioned them is because they are designed to work at high speed and the moving parts are made of hard steal that does not wear easily plus you can pick them up cheap at salvage yards.
     
  7. Mosaic

    Mosaic Well-Known Member

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    From the standpoint of economy, how about placing solenoids like these
    24 VDC PULL-TYPE SOLENOID | AllElectronics.com
    inside plumbing fittings mated to the tubing to act as flow management. Let the tips of the solenoid actuator plug the tubes. The water would cool the solenoids.


    I think 3v0's approach has strength from not requiring a pressure regulated system which is required to prevent flow fluctuations as different streams are actuated. I'd vary it slightly to achieve pressure regulation by allowing the pump to have a riser tube overflow (as high as the rainfall transom).
     
  8. #12

    #12 New Member

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    I can see the logic in the 3v0 idea. I even think he's on to something because the initial velocity of the droplets in the waterfalls on Utube is very small.
     
  9. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    I like the ideas so far but I am woundering if any of them exept maybe the injectors could prevent that last drop from falling after it is supposed to stop. The key would be to keep the exit of the the valve/gate as short as posible. Andy
     
  10. Sceadwian

    Sceadwian Banned

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    Yes sharp actuation is required. If the water is actually forming a stream when it exits the valve then it's not a problem as the 'last drop' if there is one will be so small as to be inconsequential unless the mechanical construction is sloppy. Don't worry yourself into a corner before you try a basic prototype.
     
  11. #12

    #12 New Member

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    Good point, Scead.
     
  12. kagan09

    kagan09 New Member

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    would i need a PCB design to get the project done
     
  13. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    You would need somthing but I would prototype 1st. Andy
     
  14. Sceadwian

    Sceadwian Banned

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    Probably not, you can do most projects on perfeboard or on breadboards.
     
  15. Mosaic

    Mosaic Well-Known Member

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    Valves don't drip unless they have a leak. The cohesiveness of water does not encourage the breaking of a stream to form a drop. If a valve is shut off properly the remaining water in the tube will form a meniscus due to surface tension and not drip. Have u ever used a pipette in high school chemistry class?
     
  16. Sceadwian

    Sceadwian Banned

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    All real world valves have a leak rate, engineering 101.
    You can not design for 0 leak, it can't occur in the REAL world. Give that same pipette a thermal variation or pressure on either side.
     
  17. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    A pipette will drip untill a vacuum is formed. The exit of a valve even more. The exit end needs to be small and short. After the flow is cut off the water left on any surface after the valve may drip off. The movment of one valve may be enough to brake the "meniscus" on a neighboring valve assy. This may not be much and never noticed from a distance. Just somthing to think about. Andy
     
    Last edited: Dec 21, 2010
  18. Mosaic

    Mosaic Well-Known Member

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    Anyone has any approaches for converting 1 bit depth video from, say Premiere' into a line by line sequence via USB to an MCU?
    Standard DVD NTSC resolution is 720 dots wide. It would have to be scaled to the # of streams in use.
     
    Last edited: Dec 22, 2010
  19. kagan09

    kagan09 New Member

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    where can i find cheap micro solenoid valves ?
     
  20. Sceadwian

    Sceadwian Banned

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    Build them yourself. Magnetized pin + wire wrapped core = solenoid. Cheaper by far than buying one.
     
  21. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    I would try some surplus supplyers. Andy
     

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