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interlocking switch

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by Adrian116, Jul 30, 2008.

  1. Mikebits

    Mikebits Well-Known Member

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    One point. How about the middle switch position detection that the OP wanted? Another switch pole maybe?
     
  2. john1

    john1 Active Member

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    Hi Ken,

    You have improved on that circuit.
    As to the red and green, Adrian doesnt mention anywhere that he will use two different colours, but yes it is quite reasonable to think so.
    And yes, to appear similar brightness they would need slightly different resistors.

    Curiously, i was also thinking that the switch might be able to discharge the opposite capacitor but i didn't set anything down, nor did i think how it might do that.
    I was thinking along those lines, simply to enable the use of reed-switches, but i did not actually come up with anything.

    I am most taken with the simplicity and small number of components in this circuit.
    I have taken the liberty of re-drawing the same circuit, using reed switches, and adding a picture of the type of switch.

    The OP (original poster) has a choice of ordinary relays or reed switches.
    As to the contacts getting damaged, ive abused relays for years and i think that any normal relay could discharge a few microfahrads without a problem, but using the switch is of course much better.

    We have not heard from Adrian in a while.

    Regards, John :)

    ***************************

    [​IMG]
     

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    Last edited: Aug 3, 2008
  3. Mikebits

    Mikebits Well-Known Member

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    That is pretty clever :)
     
  4. dave

    Dave New Member

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  5. john1

    john1 Active Member

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    Mikebits,

    Just seen your last post,
    Did Adrian want indication for the "OFF" ... ?
    I dont recall that, he may have mentioned it as a possibility, i could look back i suppose.

    Cheers, John :)

    last but one now
     
    Last edited: Aug 3, 2008
  6. john1

    john1 Active Member

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    an indication for the OFF might be difficult,
    as those type of switches have no contact in the middle position.
     
  7. Mikebits

    Mikebits Well-Known Member

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    Here is the requirements as I understand them.

    With that said, I would recommend holding off anymore effort until we hear something from OP. This could turn into a talking to ourselves sorta thing :)
     
  8. KMoffett

    KMoffett Well-Known Member

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    Mikebits,

    I agree!...I'm putting my brain on hold. ;) Oops...there I started thinking again.

    Reading back over the thread, it looks as if Adrian has changed perameters as different questions came up...like adding "Clear" and 4 LEDs as opposed to two, from Torbin's attempt to flesh out the design requirements.

    Ken
     
  9. Adrian116

    Adrian116 New Member

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    Hi John, I'm sorry to reply so late because my LCD have some problem that nothing was shown.......

    Actually, indication for the "OFF" is necessary for a single 3 ways switch since the customers may choose neither "clean" nor "don't disturb",
    But the difficulty should be focused to if there have such a switch which appeared in your designed circuit.

    "OFF" function can be eliminated if two 2 ways switch are used. But remember that they should be interlocked.

    Thank you John for helping~
     
    Last edited: Aug 3, 2008
  10. john1

    john1 Active Member

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    Hi Adrian,

    Hope your LCD is alright now.

    Could you accept the off as being neither "clean" nor "don't disturb" ... ?
    Unless you want it as some sort of 'double-check' ?

    I'm afraid i am having trouble following the rest of your post.

    Using a single switch,
    is effectively "interlocked",
    because it can only be in one position at a time.

    Cheers, John :)
     
  11. Adrian116

    Adrian116 New Member

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    The off being neither "clean" nor "don't disturb", then what the "OFF" function be? Actually the "OFF" is used turn off either "clean" or "don't disturb" alarm.

    I am also think that a single switch is better. You may forget about 2 toggle switches:)
     
  12. Mikebits

    Mikebits Well-Known Member

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    I started thinking about this a little more, and I came up with something I thought might work for ya, and it is very simple to construct. To boot, you do not even need to reverse engineer your remotes as this will just wire in place of a remote switch.

    Now I do violate your single switch rule but before you dismiss this idea read on. This configuration would have two switches, one would be dual DPDT with OFF and two momentary contacts. Like
    Momentary - OFF - Momentary
    Second switch would be a pushbutton used to clear alarm. Also this circuit uses no expensive relays and consist of 10 parts.

    So 1 switch set alarm and notifies remote and lites LED, other switch clears LED and notifies remote.

    Parts List

    • SW1 - Pushbutton switch
    • SW2 - Dual DPDT
    • Q1-Q2 SCR Value TBD
    • D1-D2 LED value TBD
    • R1-R4 Resistor

    I did not select any parts as I did not want to do the research and find this idea is not going to be to your liking. So will help select values if you wish to continue.

    One question, what will the remote be doing? will it notify a computer or something?

    Circuit attached
     

    Attached Files:

    Last edited: Aug 4, 2008
  13. Adrian116

    Adrian116 New Member

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    Is the switch 1 used to reset all the alarm status to "OFF"?

    Is your idea like the following?
    Toggle the "momentary-off-momentary" button to set either "clean" or "do not disturb " to alarm status. If I want to reset the alarm status to "OFF", press the reset button, isn't it?

    the remote is used to notify a receiver, the remote and the receiver is a set of security device.

    Thank You.
     
  14. Mikebits

    Mikebits Well-Known Member

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    Well, I think you get the idea.
     
    Last edited: Aug 4, 2008
  15. Adrian116

    Adrian116 New Member

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  16. Torben

    Torben Well-Known Member

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    Hi Mike (and Adrian and John and Ken),

    I was up late last night putzing around with this idea and came to a few conclusions, which it looks like Mike has also reached.

    The whole thing would be fairly easy if we assumed the use of a 3PDT switch instead of a DPDT switch--otherwise Mike's idea of the separate "Clear" button is necessary. Using a DPDT centre-off toggle switch and a pair of relays I built a simple circuit which pulses the relay and lights the appropriate LEDs. I wired the DPDT switch so that when going to "Please clean" it would discharge the capacitor on the "Do not disturb" side and vice versa as Ken suggested, but I haven't yet figured out how to wire it to do that when returning to the centre-off position. I'm not sure it can be done without the 3PDT switch. Anyway, this means that the thing can still be confused by switching rapidly back and forth between centre and one side. Rapid switching all the way from one side to the other works fine, though.

    Getting the centre-off position to trigger a pulse on a third relay is also slowing me up. I am currently thinking about diode-transistor logic to try to get that effect.

    However, it seems to me that the unit will wind up being fairly bulky in the end if it contains three relays. If the remote control contacts need only that one side be brought high or low then using transistors instead of relays may be able to save quite a bit of space (and some current too).

    Anyway, I'm kinda rambling here. I have to go do some housework but I'll take another look at this later on.

    Mike's question about whether the remotes have unique codes or frequencies or such is a really, really good question too. :) The whole system would kind of break down if one unit triggered the central receiver for several rooms.


    Torben

    Oh yeah. I've attached the basic schematic I've been using so far. It's drawn just for one side and only addresses the pulse generation. If I get a bit more time later on I'll draw out what I actually have wired up. This is just the RC differentiator/relay portion of the circuit.
     

    Attached Files:

  17. Torben

    Torben Well-Known Member

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    Hi Adrian!

    I have some more questions. Some of these questions aren't about the actual circuit, but they may help us help you better if the answers mean that we can look at other possible solutions.

    Is this actually for a large-scale installation in a real hotel? If so, how many rooms must be serviced, and what is the expected range?

    Is using the remote controls your idea, or the hotel manager/owner's? I ask only because it sounds like they already have something central installed.

    Do you know for sure that you can get enough remote controls with unique codes/addresses/frequencies/whatever to handle all the rooms?

    Why do you want to do this with relays and capacitors only? If semiconductors and ICs were allowed it could possibly be made smaller and cheaper.

    What is your expected budget for each unit? What about the budget for the whole system?

    What is your deadline?

    What electronics experience do you have? Do you have the ability to load HEX code onto a microcontroller such as an 8051 or a PIC or something?

    Would it be possible to use a rotary switch instead of a toggle?

    I am sure I've forgotten some questions but if you can answer the above it might help us to help you.


    Torben
     
    Last edited: Aug 4, 2008
  18. Mikebits

    Mikebits Well-Known Member

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    Ya know, when I was in the Navy we had this piece of gear for sat-comm stuff. Anyways I remember it had this really cool switch on it. It was 3 way, but middle position was push button. Now that would be cool, just can't figure out what you would call it. So it was like ON- PB -ON. I ordered a few switch catalogs to see if anything resembles what I remember.

    _______________Edit__________________

    Brain fog is clearing. It was a rotary knob switch, with a center PB...
     
    Last edited: Aug 4, 2008
  19. Adrian116

    Adrian116 New Member

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    :)
    Thank You so much
     
    Last edited: Aug 4, 2008
  20. Torben

    Torben Well-Known Member

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    Hello again Adrian,

    By "range" I mean how far must the farthest remote control be from its receiver.

    I agree--wired would be more reliable. I don't know whether you can get the range, reliability, and ability to tell one room from another using the remote controls. Using microcontrollers and proper RF modules it should be doable but it's a pretty big job.

    I thought the receiver was going to be in a central location? Are you saying that the remote control is going to be in something the customer can carry around the room? I thought there would be a switch on or near the door which the customer could use to control LEDs inside and outside the door, while the remote would send the state to a central location where all rooms could be monitored at once. Which is it?

    OK, that opens things up a lot.

    Microcontrollers might be the easiest and cheapest way to solve this problem.

    OK, that's good to know.

    Thanks for the answers, and if you can answer the above questions (and any others you think we might ask) things can move forward.


    Torben
     
  21. Adrian116

    Adrian116 New Member

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    Is this switch like the one shown in the attachement?
     

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