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REQ : Stepped lighting.

Discussion in 'Electronic Design' started by I.P.off10, Mar 30, 2007.

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  1. I.P.off10

    I.P.off10 Guest

    a request for a circuit/layout for light switching that will turn on

    low level lights 2 or 3 steps in front & 1 behind as a person walks

    along a corridor or up/down stairs. Component list & values would also

    be required if possible. My thanks for your consideration.


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  2. John Barrett

    John Barrett Guest

    Option 1.. low power laser range finder at one end of the area to be
    covered, with microcontroller to read the range and control the lights (low
    level ?? perhaps LED ??) .. this setup would be able to determine direction
    of travel and do the 1 behind and 2 in front requested.. practically
    speaking, this setup would be limited to 4-6 lights due to cabling
    considerations

    Option 2.. ultrasonic or laser sensor at each light -- with wiring between
    the lights to allow one light's trigger circuit to also enable the adjacent
    lights -- this could be done without a microcontroller by activating 2 in
    front and 2 behind, or with a microcontroller at each light.. this system
    can be modular... extensible to any length of light string with no more than
    4-8 wires between each module -- CAT5 cable and connectors would be optimal.

    if you are talking more of a strip light than a series of wide angle point
    sources... the same techiques can be applied with the lights in banks, or
    with more extensive microcontroller control to actually turn on individual
    closely spaced sources in sequence.

    You are welcome to contact me via email if any of these options address your
    problem.
     
  3. hmm, force sensing resistor, 5 or so diodes, couple of logic gates,
    and of course a 555, just to annoy Bill Sloman


    martin
     
  4. Guest

    I'm more anoyed that you didn't notice that this is actually a job for
    an off-the-shelf person sensing circuit, that you can buy in any
    lighting shop.

    IIRR the fittings contain an infra-red sensor which picks up human
    body warmth - spread a couple of them along the corridor and the job
    is done. No need for logic or a 555.
     
  5. John Barrett

    John Barrett Guest

    ummm really ?? they make on that will turn on several banks at a time ?? for
    instance, if you have 8 light sources , it will turn on 123, then 234, then
    345, etc as you walk down the hall ?? and conversly 876, 765, 654, etc as
    you walk the other way ?? always with 2 banks on in front of you ?? Person
    sensors that I'm aware of only control one circuit.

    I was envisioning something more along the lines of a strip that could be
    installed along the base molding of a hall way, powered by a single wall
    wart... and if the OP is interested in the modular approach, one that could
    daisy-chain for a hallway of any length.. say in 2-4 ft sections.

    An IR sensor would certainly be a viable technique also.. but some logic is
    going to be needed for the "feed forward" to turn on lights ahead of the
    person walking no matter which way they are walking -- logic gates or an 8
    pin PIC/AVR -- doesnt really matter much.... If I put some more thought into
    it -- I could probably figure out a way to do it with no more than 8 wires
    between stations and discreet logic only -- or 4 wires (2 power, 2
    differential data) and a MCU...

    dozens of ways to solve this one -- need some more info to pick the one that
    best fits the OPs intentions.
     
  6. Like the subject line says.....
     
  7. Guest

    The logic is a red herring. The OP just wants to walk in a pool of
    light, and having the lights stay on few feet behind him (which he
    doesn't need) is a cheap price to pay for having them come on a few
    feet in front of him, and greatly simplifies the task.

    It is always as well to keep in mind that you want to provide what the
    customer needs, rather than what they think they want.
     
  8. John Barrett

    John Barrett Guest

    hmmmm you are a mind reader ?? you can figure out the complete details of
    what the customer wants based on an incomplete description ?? The original
    post didnt specify anything more than "low level lighting" -- thats easy --
    LEDs.... what was not specified was how many LEDs, what spacing, total
    length of the LED array, desired form of the lighting array -- the circuitry
    in general is simple enough, but choosing a specific implementation to match
    the target hardware requires a bit more information than we have gotten so
    far.
     
  9. john jardine

    john jardine Guest

    Yes.
    The image that instantly sprung to my mind, was that recent "wouldn't it be
    nice if ..." TV advert with the American voiceover (no idea what they were
    selling though).
    My problem is that once the image is formed, there's no escaping it :)
     
  10. Guest

    I'm not a mind reader, and I can't figure out the complete details of
    what the customer wants on the basis of an incomplete description.
    What I do know is that what the customer asks for usually hasn't got
    all that much to do with what they really need, and you have to do
    quite a lot of "what if" questioning before you start putting in any
    serious time on detailed implementation. It is a very good idea to
    strip the concept down to the bare minimum at some point in this
    process, because it can save you and the customer a great deal of
    unnecessary development time if the bare minimum is something the
    customer finds that they can live with.
     
  11. Ross Herbert

    Ross Herbert Guest

    I think the OP achieved what he set out to do - he got everybody
    hooked on thinking he had a genuine requirement for such a device when
    in fact it was a hoax.
     
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