best way to control lot of buttons

Discussion in 'General Electronics Chat' started by anhnha, Mar 7, 2015.

  1. anhnha

    Thread Starter Active Member

    Apr 19, 2012
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    Hi,

    I am thinking about an idea to do a circuit to check who is present or not at the working room.
    The idea is as follows:

    There are about 40 people working in the room.
    I want to use do a circuit using Pushbutton Switches A16 as in the link.

    http://www.ia.omron.com/products/family/1101/

    Each person will be assigned a button, therefore there will be 40 buttons.
    Each day, when a person goes to the room, he/she should press his/her button and the led in
    that button light up.
    At the end of the day, he/she will press the button again and the led will be off.
    To control the on/off of leds attached in these buttons I will use a microcontroller.
    However, there will be a lot of wires and soldering work here.
    Each button there will be a two wires for switch and two wires for led.
    So for 40 people there will be 80 wires at least.

    Could you suggest some idea to make this circuit more elegant (simple, less wires, less soldering work)?
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    What some pushes someone else button ?
    Why not use an RFID unit. Simple and less wires.
     
  3. tcmtech

    Well-Known Member

    Nov 4, 2013
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    Micro managing at its best! :(
     
  4. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Perhaps you could arrange the switches in a 8x5 matrix and use the microcontroller to actively scan them. With some clever multiplexing it may also be possible to drive the LEDs from the same matrix that reads them by connecting each LED in parallel with its switch. A closed switch will short out the LED and prevent it from illuminating so make closed the "not present" state. I'm assuming latching switches are used but it may be possible to devise a scheme using non-latching.

    There's still plenty of soldering and wiring to do, though.
     
  5. anhnha

    Thread Starter Active Member

    Apr 19, 2012
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    Good night!
    The main circuit is to check if someone going to work or not so that we can call them if necessary.
    So no one will be interested in pushing other buttons.
    The control is very simple. The first time pressing the button, led will light up. If the button is pressed again, the led will be off. Now if we press the button, it will light up again.

    I haven't thinking about that but RFID may be not allowed in my workplace.

    I also think so. PLC will be very expensive and require lots of input/output.
     
  6. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Key card or Fobs are not allowed at work.. that's funny.

    How far are the buttons from the LED's
     
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    [​IMG]
     
    Roderick Young likes this.
  8. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    ^^ This is all you need to do..
    Why do you need a micro to control the LEDs?.. Thats what the toggle switch is for?

    But do you not have a time clock or other attendance system?
    Do you not have a paging system?
    Do you not have managers?
    What happens when someone forgets to flip their switch either at the beginning of the day or the end?
    What problems are you currently having that you think you must resort to this switch/led system?
     
  9. anhnha

    Thread Starter Active Member

    Apr 19, 2012
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    Well, actually I want to use these buttons because they look nice and each has a built-in led
    Well, the problem is that I want to use these buttons. They look nice and have built-in led without external resistors.

    [​IMG]

    At present, we have a tablet on the wall in which each person represented by his/her picture. The picture has two side. One side has green background
    and the other side has red background.
    When a person going to work, his/her flips the picture so that green side is at the front. And when before going home, he/she will flip the picture and
    the red side now is at the front.
    With that case, when someone looks at the table, he/she can easily know who is absent ( red side will be at the front).
    So, I am thinking about replacing these pictures by buttons.
    If one is present, the button will light up.
    It is just a mistake and we will remind them again.

    Well, we do have. This system is not supposed to strictly control who is present or not.
    This is just a quick way to see/summarize who is present (maybe not 100% correct).

    As I said, the leds are built-in on buttons. And there are lots of them (about 40 leds). So I want to use microcontroller because micro is not expensive at all.
    Toggle switches doesn't look nice for this purpose!
     
  10. anhnha

    Thread Starter Active Member

    Apr 19, 2012
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    Yes, I may ask for again but not sure it is approved.
    The led is built in on each button.
    It is right under the button.

    [​IMG]
     
  11. anhnha

    Thread Starter Active Member

    Apr 19, 2012
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    That seems interesting, I will look at this more. Thanks for the idea.
     
  12. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    It would make this a lot more sense if you located an equivalent lighted switch with a push-on/push-off function. No need for a lot of long wires or a microcontroller.

    Ken
     
  13. R!f@@

    AAC Fanatic!

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    With the switches OP showed it is quite simple.
     
  14. anhnha

    Thread Starter Active Member

    Apr 19, 2012
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    It is hard to do this because I want to use the available buttons. A microcontroller is not a problem at all. It is also small and inexpensive.
    I want to place all button on a table and hang it on the wall. So I want to make it look neat, clean and not so big. It would be nice to look as if a picture on the wall!

    I want to layout all buttons (with built in leds) on this board. At the front are button and the back
    is wring and microcontroller.
    The problem is that how to make it look neat, not so cumbersome.

    [​IMG]
     
    Last edited: Mar 7, 2015
  15. strantor

    AAC Fanatic!

    Oct 3, 2010
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    these Omron switches that OP likes do come in a pushon/pushoff configuration. OP should choose the buttons with "A" (ex: A16L-J[]A-5D-1) in the part number, not "M" (ex: A16L-J[]M-5D-1).
     
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  16. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Some years ago, companies running buses in our city decided to implement kind of top class service.

    The driver, before letting you get on, checked if there was space available simply by looking at a board where a LED showed a passenger occupying a certain place. A sensor in each seat, able to detect even young kids, provided the information. Could something like that be of help?
     
  17. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Can I assume that the tablet was someone else's idea and you want to improve on it? Because to me it seems that the tablet solution is the better solution and if you had come up with the tablet solution you would realize that going for buttons is taking a step backwards.

    If the tablet is too small, get a bigger tablet. Or get a large touchscreen monitor and cheap computer. The benefits of a tablet or touchscreen computer are many:
    1. It can be easily reconfigured as employees leave/join the company, or as work rooms are added/removed from the building. If another workroom is added, all the work is done for you already, just copy the program; with switches you need to make an entire new board.
    2. it can be easily networked and integrated with management systems
    3. there are more but I am out of time
     
  18. anhnha

    Thread Starter Active Member

    Apr 19, 2012
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    Well, it would be great if that is the case! :D:D
    I will order these buttons.
     
  19. MaxHeadRoom

    Expert

    Jul 18, 2013
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    You could also get away with 3 wires for each P.B. if you use the same common for P.B. and LED.
    Max.
     
  20. anhnha

    Thread Starter Active Member

    Apr 19, 2012
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    It is interesting but much more complicated than my case.
    I think a sensor at the seat is not appropriate for office as people sit down and stand up regularly.
     
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