transmit wirelessly from laptop to LCD TV??

Discussion in 'Amateur Video Production' started by Sammy Abernathy, Dec 7, 2013.

  1. I want to be able to see my laptop's screen on my 46" LCD TV. Is there
    a cheap way I can do this wirelessly and, if so, how?

    Thank you,
    Sammy Abernathy, Dec 7, 2013
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  2. Sammy Abernathy

    Paul Guest

    Locate the laptop, next to the TV set. Plug in the VGA cable.

    Now, sit on the couch, with a wireless keyboard and wireless mouse.
    You can enter input to the laptop remotely that way.

    Doing it this way, there will be a tiny bandwidth requirement,
    to ship keyboard and mouse commands over the wireless keyboard
    and mouse protocols.

    To ship video wirelessly, from laptop to large LCD TV, requires
    an extraordinary amount of bandwidth. The technology needed
    is expensive, or the technology used, degrades the noise
    floor for other wireless technologies (your wireless file
    sharing runs slow, your wireless Youtube viewing is affected).
    While there are solutions that can transmit video wirelessly,
    I'd choose to find some other solution.

    Paul, Dec 7, 2013
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  3. When I saw your first sentence I started to think "But Sammy asked for
    wireless" - then I read further and realized the elegance of your idea

    One comment - lots of today's laptops have an HDMI output, which would
    work very nicely, and following your idea, the cable could be short, so

    I have a cheap desktop computer next to my TV, and I do just what you
    say. It works well, except that it can be fatiguing to read the screen
    for 42 feet away (actually, it's just 10 feet, with a 46" monitor).
    Gene E. Bloch, Dec 7, 2013
  4. Sammy Abernathy

    Paul Guest

    Companies like this, never stop working on this stuff.

    Here, they offer a pair of boxes running at 60GHz!
    And the input and output are HDMI. Only $450 and
    in the pre-order stage. At least this wouldn't
    interfere with the Wifi.

    There was also a version using UWB (ultra wide band),
    with perhaps some kind of link compression, to make
    the output fit. I would not expect the price to fall
    much, with the uptake rate of products like this.

    This one at 5GHz, is likely in the same band as some Wifi.
    This is more likely to use some compression, than the other one.

    And this is an earlier UWB effort. Listed at $725.

    The problem with compression on the link, is what happens if you
    attempt to view a video on the laptop. The 46" TV screen may not
    keep up, and could show visual artifacts. Compression on these
    schemes, works best for static images, like PowerPoint
    slide shows put on by salesmen.

    That's why, before you buy one of those, you need to see
    a review of the hardware, and how badly it messes up
    movie playback.

    With the 60GHz one, I guess it makes microwave popcorn
    for you, at the same time as you watch your movie. That's
    pretty close to the 100GHz, that US Army device used to
    repel protesters works at. This is the one that makes
    you feel uncomfortably warm, so you run away... The
    RF on this, likely runs at a higher power level
    than the Gefen :)

    Paul, Dec 7, 2013
  5. At $450 I'd probably opt for a 10 meter HDMI cable :)

    Although it won't repel protesters, you could use the cable to take
    care of a horse thief.
    Gene E. Bloch, Dec 7, 2013
  6. Sammy Abernathy

    Brian Guest

    Good idea Paul. The only problem is that laptops have special keys that can
    only be accessed by the laptop. It depends on what the poster wants to do.
    I might consider doing the same as I want to play back a video from Vegas
    in full screen to see what it looks like on a TV.
    Brian, Dec 8, 2013
  7. Sammy Abernathy

    j Guest

    j, Dec 10, 2013
  8. Sammy Abernathy

    Paul Guest

    That is so cool. Who would have guessed you could directly
    modulate a laser pointer that fast ?

    This is another way to modulate light, with an external
    modulator. This comes in handy if direct modulation
    of a laser isn't fast enough.

    "This device is called a Mach-Zehnder modulator"

    The only problem with something like that, is it isn't
    designed for FSO (free space optical) use. It would be more at
    home with 50u apertures and small light outputs.
    I don't know if there'd be any signal to pick up on
    the other side of the room.

    Back in school, I did a direct modulated link with a
    HeNe laser (the kind with the BNC connector on the side).
    But it was running at only 9600 baud. I would type a
    character on a keyboard, on one side of the room, and
    a 5x7 dot matrix alphanumeric display on the other
    side of the room would show the received character.
    Not much of a tech challenge, but good for a lab
    session (for credit).

    Paul, Dec 10, 2013
  9. Sammy Abernathy

    j Guest

    Thanks, I had no idea of that.
    Now, that is old school! The first gas laser was HeNe. I believe it was
    "the" laser for some time.

    I have some distant memory of using one for making holograms on a
    massive massive table.

    The technological leap to get beyond 9600 is stunning, particularly for
    twisted pair.

    You are a sharp cookie, I always pick up something from your posts.

    j, Dec 12, 2013
  10. Sammy Abernathy

    Paul Guest

    That was my so-called "experimental physics course".
    About 13 teams, and a room full of equipment, and
    let loose your imagination. The "shooting the
    ASCII character across the room" one was rather
    lame, compared to what the other teams were doing.
    I did it more for "atmosphere", than for science.
    To make the lab look more respectable.

    We had all sorts of fun stuff in the room. High voltage,
    deep vacuum (diffusion pump), and liquid helium (for
    cryogenic experiments). One of my experiments was cryogenic.
    And someone else did an experiment at 4 Kelvin. Mine was
    a bit warmer than that, and rather boring. Also
    a bitch to write up later.

    I was surprised more students didn't sign up for that
    course, because you got to define your own experiments
    and build them. Not like regular courses, where you
    did "recipe experiments" out of a book.

    One of my fun projects, was building a nitrogen gas
    laser. For one of those, you put Brewster windows on
    the end. The gain of the gas is so high, to get full
    power only takes one pass. Whereas lots of other laser
    types, like the classical HeNe, need a thousand reflections
    up and down the tube. Mine was more like a "UV flashlight" :)
    It's not much of a laser - but it *is* easy to build.

    (This picture shows the shape, but not the details.
    Mine used nitrogen gas, and output is ultraviolet.
    Mine was a pulse laser, firing rate 0.5 pps.)

    For that one, I provided my own power supply. I'd
    built a high voltage DC source at home (TV flyback
    and doubler), and brought it in to run the laser.
    The power supply used about 30 watts or so while running.

    One other (Masters) student, spent two years part time
    working on his dye laser (it wasn't even for his thesis or
    anything - just a project), and never got it running.
    And not for lack of trying. That's much harder to do,
    because fluorescein-like substances in water, the light
    needs to make a lot of passes up and down the tube, before
    you get full output. You need precision alignment,
    partially silvered mirrors, and so on. He became an
    expert at making mirrors. He was all the inspiration
    I needed *not* to make one of those :)

    Not every science experiment produces output. Each
    failure "builds character".

    Paul, Dec 12, 2013
  11. Sammy Abernathy

    j Guest

    Most people like details more than abstractions. If you have any
    interest in this, look up MBTI (personality typing) and S (Sensors, 85%
    of population) versus N (Intuitives) types.
    Yeah, I see that. Interesting.

    Whereas lots of other laser
    Obviously a highly detailed and obsessed personality!
    I have said to people that were struggling with something or another
    that failure is always an option! I also say that: No matter how bad
    things are, they can get worse!

    I need a little success somewhere, to balance out the failures. That is
    the great thing about mindless physical work. There is always some

    OK. I have a weird "household" physics question that I can not sort.

    I have a "friend" with a water heater in her basement. Somehow the cold
    water pipe had gotten knocked off. So she fills up the hot water heater
    with a garden hose (and turns the hose off) and then has hot water upstairs.

    What possible physics could do that?
    j, Dec 13, 2013
  12. Sammy Abernathy

    Paul Guest

    What is the density of hot water ?

    What is the density of cold water ?

    Would there be enough convection to heat a house ? Unlikely.

    I thought those systems needed a pump ?
    Otherwise, it would be hard to get enough
    transport to get the job done.

    Filling the tank with the garden hose, implies
    a closed system. The act of filling the tank,
    displaces water or air. So stuff moves around.
    Maybe that's enough to (temporarily) transport
    some of the hot water upstairs.

    Some water devices, they're set up to have the
    cold water enter low or enter high, to give
    the "heat reservoir" certain properties. Like
    near-instant heat, or in other cases, intermixing
    so that the thermostat comes on and heats the thing
    sooner when it comes under load. So you also have
    to look where the water is coming into the thing,
    to understand what kind of water will be traveling

    If you fill with a garden hose, you can only do that
    until the system is filled to about 60 PSI. (Or if it's
    open some where, water is running over the floors :) )
    Once the system is charged, I don't think connecting the
    garden hose will help. If you want to start over again,
    you might have to drain it a bit, then use the pressure
    from city water, to do your transporting.

    The best example of convection heating, was the old
    furnace design. Houses across from where
    I lived had those. The furnace in the basement,
    has no electric motor and fan, to distribute hot
    air through the house. Hot air rises by convection.
    The pipes have to be many times bigger in diameter,
    for that process to work. The church I used to go to,
    was similarly heated. In the basement there, were
    three furnaces, each with enormous pipes, and that's
    what pushed hot air through the church. (All by
    convection.) They used to burn something like $8000
    worth of furnace oil a year through those things.
    And that was back when furnace oil was cheap. The
    nice thing about those furnaces, is if you reline
    them once in a while, you can get 50 years out of them.
    Not having a lot of fancy tech, they're quite reliable.
    It you have to get one out of the basement, they're
    also quite heavy. "Modern" folks would not like those,
    because the enormity of the design, there's no space
    left in the basement for your beer fridge :)

    Paul, Dec 13, 2013
  13. Sammy Abernathy

    j Guest

    The difference in density is slight,under a percent or so.
    This is what they call domestic hot water,like to take a shower.
    Hot water heaters have a cold water shut off. I haven't seen this but I
    thought perhaps this was filled before the shut off, then had the shut
    off closed.
    Usually the hot water takeout is higher than the cold.

    I have the remnants of a converted coal burner in the basement.I saved
    the pipes stacked inside each other. Some are nearly 3' in diameter.

    The church I used to go to,
    Oh, mine dominates the center of the basement of my '29 house.

    j, Dec 13, 2013
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