Hacked Gadgets Forum

December 8, 2009

Button Code – Single Button Code Entry System

at 2:13 am. Filed under Cool Gadgets, DIY Hacks, Electronic Hacks

 This is a project that I have been working on, it is just completed and ready to go! The video may be a bit dry since it is just going over the features and how to use the controller. If you want to see it interfaced to a rotary phone have a look at around 7:40 minutes into the video.

The Button Code is a system that allows a single button to act as a keypad. The user enters a 4 digit code into the system using button taps. The button can be placed where the public can access it since like a keypad there are many combinations to keep guessers from activation the system. When the correct code is entered a form-C relay is activated (Normally Open and Normally Closed relay contacts). When activated it can either activate for a programmed time or simply toggle the output whenever the correct code is entered.

This simple circuit allow for simple control of things such as:

  • Garage Door Openers – Pulse the door open button for a second to operate.
  • Lighting – Toggle to turn on, toggle to turn off.
  • Door Access – Pulse the door lock for 3 or 4 seconds.
  • Simple Security System – Toggle  alarm power on or off.


To purchase this controller please have a look at our online store.



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16 Responses to “Button Code – Single Button Code Entry System”

  1. Muris Says:

    I will feature this project on my web page today, if you don’t have any complaints 🙂

  2. Alan Parekh Says:

    Thanks Muris.

  3. vic Says:

    Nicely done. Good job interfacing all the functionalities through only 2 wires 🙂 Lots of options, too. While you’re at it, you could add the possibility to trigger the relay through the serial port, to enable home automation kind of stuff. Also you should print the max. switchable current on the product page, the relay says 10A but maybe the traces can’t hold it (hard to see through the PCB ^^).

  4. Tom Fisk Says:

    Great project!

  5. Alan Parekh Says:

    Hi Vic,

    I will have to add that. The max current is 2.5A

  6. Oler Says:

    Nice kit.
    Quite some heatsink too, im guessing thats necessary for the relay and the ability to use 9 volt battery’s.

  7. Oler Says:

    how much milliamps does it use behind the regulator @5volts ?

  8. David Says:

    Very nicely implemented.
    The “single button keypad” reminds me of the
    “Stealth Keyless Entry System”

  9. Alan Parekh Says:

    Hi Oler,

    The heatsink is needed since the relay could be activated continuously. When the relay is activated the circuit current draw is 100mA.

  10. Alan Parekh Says:

    Hey David,

    Nice find! Looks like someone else had the same idea.

  11. Paul Says:

    Nice project, I like the way it can easily be setup to accept the old rotary phone as input (I’m currently trying (via auctions) to buy some old rotary phones for projects at the moment).
    When the video started and it showed your name I was wondering how your last name is pronounced, luckily for me (and my curiosity) you pronounced it at the end of the video 🙂

  12. John Says:

    I love the 1-button implementation, that makes it extremely versatile… I could imagine a dozen different contexts and devices that could be used with it.

    The rotary phone use is awesome btw, connect it to a hidden door in the floor and you can be like a james bond villan.

  13. منتدى Says:

    The rotary phone use is awesome btw, connect it to a hidden door in the floor and you can be like a james

  14. paul Says:

    Is this the next prize in the contest?

  15. Berni Says:

    This is a very nice idea, nobody would suspect the little button to be a combination lock.

    Oh and you can dial telephone numbers in the same way with a switch(thats why a rotary phone also works on it)

  16. Alan Parekh Says:

    Hi Paul,

    I am thinking this would make a great contest prize. 🙂

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