Self Buzz from Apartment

Discussion in 'General Electronics Chat' started by Panache, Jul 27, 2014.

  1. Panache

    Thread Starter New Member

    Jul 27, 2014
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    Hallo everyone, newbie from Ireland. Always fascinated by Electronics and Mechanics and everyday is a learning curve for me.

    Anyway........I am planning on making a device that will self buzz me into the apartment. We only get 1 electronic fob per flat and problem is either my girlfriend or me has the fob at one time and that leaves the other person stranded and having to wait for someone to buzz us in.

    I have these components :

    - Arduino Uno R3
    - Breadboard
    - 1k and 4k7 resistor
    - 4n25 Optocoupler
    - BC548B NPN transistor
    - Jump wires
    - 5v led x2
    - 12v led
    - 9v polaroid battery


    Well this is about all. The intercom system in the building is FARFISA PT510W (Wiring diagram attached).
    I have heard about using just the Transistor to bridge PIN 6(Call) and PIN 3(Common/Ground) so that PIN 5(Lock) will be activated but it didnt work when i did a mock up on breadboard. Should i be using NPN or PNP transistor.
    Anyway there was an alternative which was a circuit on this site:

    http://mouseextinction.com/2013/doorbell-buzzer-hack-for-keyless-entry/

    I tried the circuit and the led was lighting but i couldnt understand the code. My apartment is buzzed using a 4/3 digit code e.g 0123 or 123 meaning its 01/1 (first floor) 23 as apartment number.So you can omit first digit 0 and just put in 123 and it will still buzz. However in the code (http://mouseextinction.com/2013/doorbell-buzzer-hack-for-keyless-entry/) how will the Unlock be initiated as its not comparing input code to stored code so it can set pin 13 == High

    Any help will be greatly appreciated as long as i can get it working.

    Thanks.
     
  2. ian field

    Distinguished Member

    Oct 27, 2012
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    You can probably buy the blank fobs, I think the ones at the flats where I live were supplied by Radiospares, but the fobs have to be programmed.

    The flats recently had the fob entry extended to the bin rooms, also they put iron gates on the entrance to the pram sheds - the regular fob opens the bin rooms, but although the LED changes colour on the iron gate pad, it doesn't unlatch unless you have the right fob.

    If any old Tom, Dick or Harry could program an Arduino to open the door security, it would all be pretty pointless.

    The landlord can usually supply extra fobs at a price - or a neighbour might part with an extra one for a small fee.
     
  3. Panache

    Thread Starter New Member

    Jul 27, 2014
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    The Estate agent who runs/maintain the whole building which has apartments owned by several landlords insist on 1 fob per apartment unless there are 2 tenants sharing listed on the leasing contract. So if i had a wife and 3 grown up kids they would still regard it as 1 tenant since its 1 family.
    I have an extra fob which i had from last apartment in same building but it still has to be programmed by them and they refused to have 2 active fobs in 1 apartment.
    Thats why i am having to resort to an alternative.
    Is there an intercom system i can buy to replace what i have so it will somehow work with a mobile, an infra-red signal, a remote control or something ????
     
  4. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    Why not clone the fob you have. I know it is not a simple task but with the right knowledge and equipment it should be possible.
     
  5. ian field

    Distinguished Member

    Oct 27, 2012
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    Anythings possible - you could get a 433MHz short range link and hack it into the intercom panel to simulate lifting the handset and pressing the key button.

    Sooner or later the landlord will want to inspect the property - probably best if you don't have bundles of wires sticking out of places they shouldn't!
     
  6. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    You will need to hack into the panel in your flat to get access to the two terminals on the pushbutton switch that unlocks the door. You can purchase a wireless, remote switch receiver module/fobs on the internet. It would have to have enough range to reach your flat from the door. The receiver's output contacts would then be wired in parallel with the flat's pushbutton. And...Bob's your uncle!

    Ken

    Added: Something like this:http://www.lightinthebox.com/vgg06-dc-12v-315mhz-2-channel-wireless-remote-switch-2-remote-controls_p1257497.html?utm_source=mb_Shopping&utm_medium=PCS&litb_from=paid_pcs_shopping&utm_campaign=2689&CA_6C15C=620011720000515835
     
    Last edited: Jul 27, 2014
  7. Panache

    Thread Starter New Member

    Jul 27, 2014
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    0
    Thats some info i am seeking. Thanks so much for the responses. As for the Landlord he doesnt mind he understands we need a way to get around this so even if it meant having wires around the receiver in the apartment he doesnt mind he is aware of the issue.
    Anyway i have access to the receiver i opened it and it looks exactly like the attached file. So the Buzzer comes in through pin 6, pin 3 is ground all i need is pin 5 to activate and simulate a push button to unlock the front door.(i am guessing pin 1 and 2 are irrelavant as its Mic and Speaker for comms to the main door)
    As for wireless remote the range might be an issue i am on the 6th floor and from the door to my apartment considering i was on ground floor its still a good 60-70metres not mention the vertical distance to my apartment.

    As for solutions which can be sourced on ebay/internet please include links.

    Kind Regards.
     
  8. ian field

    Distinguished Member

    Oct 27, 2012
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    On the intercom in my flat, the key button doesn't do anything unless you lift the handset first (and then only if someone pressed the call button outside) - but there's probably thousands of different makes and models.
     
  9. Panache

    Thread Starter New Member

    Jul 27, 2014
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    Exactly what i thought as i tried to just bypass by pushing a signal back to the unlock button but didnt work. So it means the handset has to be lifted and then a signal send to unlock the door downstairs. I even tried leaving the handset off hook but it doesnt seem to work either.
     
  10. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    May require a 2-channel remote. One channel to open or close the circuit to simulate the handset pick up, and the second to activate the door lock switch.

    Ken
     
  11. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Why not one channel to initiate a timed sequence? Trigger signal is received and then simulate the handset pickup, pause, simulate the door unlock momentary switch, simulate the handset hang up. Or whatever sequence is necessary.
     
  12. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Lots of ways to skin that cat...if we just knew more.

    Ken
     
  13. Panache

    Thread Starter New Member

    Jul 27, 2014
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    Thats the way to go then,so will that remote u mentioned work Ken ?
     
  14. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Yes...but that's just conjecture, because I don't know how the handset switch is wired. The one-channel, timed sequence approach is cool, but would require some custom electronics.

    Ken
     
  15. ian field

    Distinguished Member

    Oct 27, 2012
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    If you're one of those people who like to program a PIC micro when a 555 would do, its not going to be difficult to sequence switching the hookswitch and making momentary contact on the key button in the right order and with a slight delay between the two.

    Alternatively it would be fairly simple to rig a couple of flip-flops and/or monostables, a couple of 555s would probably be OK with the existing Vcc.

    Then all you have to do is press the call button for your own flat, and before it times out use your 433MHz link to answer it and 'press' the key button.
     
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