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Newbie Furnituremaker needs help with actuating mechanisms

Discussion in 'Robotics & Mechatronics' started by skegemog, Aug 6, 2012.

  1. alec_t

    alec_t Well-Known Member Most Helpful Member

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    Having now seen your TV lift datasheet it's clear that access to the limit switches (if indeed they exist: limiting may be electronically controlled based on motor current etc) is an unknown quantity, so I don't see how one could be used to trigger the panel opening before the TV rises. IMHO the only way you could use the existing controller in a 2-motor TV/panel system would be as an open/up/down/close command signal source, and as the power source for the lift. Additional SPDT (aka SPCO) limit switches would be required and any existing ones ignored. Its power supply would not, from the figures quoted, be suitable to power an additional motor.

    Can't you just use rollers etc to open the panel as/before the TV rises? I saw in the datasheet for the TS460 I mentioned in post #17 that rollers are available as an accessory. Much simpler :)
     
  2. skegemog

    skegemog New Member

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    U
    Sounds like another approach is called for
     
  3. skegemog

    skegemog New Member

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    I have made many many pieces using the configuration you describe and this project demands a different approach.

    The ideal scenario would be if there was an IPhone / android app that would connect via wifi with a programable controller inside the piece that would then direct both the lift and the panel to operate as desired. Is there off-the-shelf componentry that would let me do this?
     
  4. dave

    Dave New Member

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  5. alec_t

    alec_t Well-Known Member Most Helpful Member

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    Dunno. Don't do IPhones or Androids or wifi :(
     
  6. skegemog

    skegemog New Member

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    Thanks for all the help with this. I've been working on this a little I came up with this scenario. The controller for the lift has momentary contact SPDT switch that allows one to raise or lower by switching from one pole to the other manually. The voltage across the contacts shows 5 VDC. Depressing in either direction activates the relays in that direction. Given all of that and if I were to construct the circuit shown in the attached diagram it seem sto me that I would at least be able to achieve the sequencial operation I seek from one switch. Do you think this will work? Will it cause a problem using the 5vdc from the TV controller to operate the relays in the panel section? Will the limit switch on the raise tv side cause a problem? ANy thougts are much appreciated!!


    View attachment 66490
     
    Last edited: Aug 19, 2012
  7. skegemog

    skegemog New Member

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    Further, it seems to me if I could get this to work, I could figure out where on the board the signal from the RF receiver is routing the current to activate the relays in the controller and patch into those to activate relays for the panel lift using the same limit switch scenario as in my diagram...
     
  8. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    A six-pin connector would suggest 2 wires to motor, and 2 pairs of wires to the limit switches.

    Can you post ANYTHING such as a pic of the PCB, terminal designations, link to a page etc, operating instructions. ANYTHING?

    I ordered one of these: http://www.tauntek.com/tinyir-learning-ir-remote-control-receiver.htm, but never hooked it up for my intended purpose. It might be beyound you to use. This could use the TV-ON and TV-OFF signals to operate lifts.

    Another idea, is to use a current detector and detect when the TV comes on. They may just require a wrap or two of one leg of the AC cord.

    The big problem is figuring out what's needed. The above is a way of making it work, but this also assumes that there is an IR repeater in the mix too.

    There are so many ways to control what you have and it's hard to guess.
    There is potentiometer feedback
    There is hall effect pulses
    There are reed switch pulses
    There is sometimes an internal limit switch and an adjustible stroke, but no external switches.

    There could be pulse to open, pulse to reverse if opening, pulse to close. etc.

    There could be an ON and it goes to a limit and off and it goes to another.

    You seem to have issues if they are not activated at the same time.

    Overloads?

    In this scenereo, I might envision the following:
    1. Suppose you had a switch or switches that had UP or DOWN and that the actuators continued until the limit was reached.
    2. Then you could use the current detect method on the TV.
    3. Have an IR repeater hidden so that that the TV gets turns on when hidden.

    So that could work for you.

    Have an override manual mechanism to move the actuators manually.
     
  9. skegemog

    skegemog New Member

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    see post #19 above
     
  10. skegemog

    skegemog New Member

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    Any thoughts about the viability of the circuit I posted above?
     
  11. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Sorry 'bout that. Anyway a pic of the board can also offer some clues.

    You have the rocker switch as the interface, but I surely can;t tell how that works either. Is it UP/none/DOWN or (UP)/none/(DOWN) or UP/OFF/DOWN or (UP)/OFF/(DOWN)

    The () signifies momentary. none means that there is no center off position.

    How many wires to the switch.

    So, you could have an interface through the rocker. But, how does the rocker operate?

    For reference, you have terms such as DPDT center off or specifically DPDT on-off-on kind of nomenclature. DPDT tells you that there a two poles and double throw. You distinguish the rest with things like (on)-none-on which would mean no center off position; one position is maintained and the other is momentary/
     
    Last edited: Aug 19, 2012
  12. skegemog

    skegemog New Member

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    I'll get a pic tomorrow
     
  13. skegemog

    skegemog New Member

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    I am guessing that the rocker switch you are referring to is the one I referred to as the "spdt activation switch". That would be operated manually
     
  14. skegemog

    skegemog New Member

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    it could be any of the above configurations. I mentioned the hardwired switch that came with the lift and that can be used independently from the RF switch. it is a three wire switch (up)/off/(down)
     
  15. skegemog

    skegemog New Member

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    I guess my question remains: is there any reason why the diagram I posted shouldn't work? Leave aside remote wireless switching for the moment
     
  16. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    I don;t see the sequential operation occurring, I'm assuming the activation switch is momentary.

    I THINK what you need to do is activate the "other" actuator on an edge. e.g One edge activates an open and the other "edge" activates a close or some such nonsense.

    In other words, you need a "pulse" based on a switch activating and a "pulse" based on a switch "de-activating"

    But, things get a little messy because of some "crosstalk".

    As I see it, say you do an OPEN, so immediately actuator A activates in the OPEN direction. Once A reaches a pre-determined point, "ACTUATOR B" is told to open" with a pulse.

    On the other hand a "CLOSE" tells "actuator B" to close and when "actuator B" reaches a pre-determined point, then "Actiuator A" is told to close.

    So, "OPEN" and "CLOSE" are going to different actuators, and whether a particular switch "OPENS" or "CLOSES" determines tha pulse that needs to get applied to "the OTHER" actuator.

    So, I think you need a way to detect the rising and falling edges of a particular switch. It may be separate from the 4 limit switches.

    Aside:

    Another way of handing the limits is to put micro switches in the power leads that open at each limit. These switches are placed in series with the motor. Across each switch contact, a diode is placed. You can easily figure out the direction. So when a particular LIMIT opens, the diode lets current flow in the "Other direction".
     
  17. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    I know where to start looking.
     
    Last edited: Aug 20, 2012
  18. alec_t

    alec_t Well-Known Member Most Helpful Member

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    The post #25 setup looks fine to me. You say the lift controller SPDT switch is momentary contact, so presumably the up/down relays in the controller are latching types. KISS seems concerned about the switch having a centre-off position, but I don't see that matters: the limit switches will ensure both motors stop at appropriate positions even if the SPDT switch contacts were to stay closed.

    Edit: My only concern would be can the 5V source provide enough current for the relay coils? To switch a hefty motor current using a 5V relay will probably require a relay coil which takes a good bit of current.
     
    Last edited: Aug 20, 2012
  19. skegemog

    skegemog New Member

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  20. skegemog

    skegemog New Member

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  21. skegemog

    skegemog New Member

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