Cell phone controlled door lock

Inspired by the knock to open hack, [ashish] put together a fairly simple DTMF decoder to control solenoid door unlocker and connected it to a Nokia 1100 cell phone. Call the phone, input the magic code, and the door unlocks.


  1. yappingboy says:

    awesome I cant wait to build one

  2. Istarian says:

    Cool. Talk about a useful diy improvement. I think the creator/author of the device should patent it, if it’s not already been patented, because this could make someone a fair amount of money, if it hasn’t already.


  3. Genome says:

    I’d like to have more than one device wired into this cellphone.
    Then I could do other stuff like turn on/off my pc.

    Quite a nice hack though.

  4. david says:

    great idea

    u know what would be sweet? the ability to text ‘run’ instructions to my home computer, or to appliances around the house, like
    “on stove 400″ for a preheat :)

  5. Wotan says:

    I agree with #2, especially if this could be modified to use a pay-as-you-go service. This is a very good idea.

    It looks like cheap cellphones with SMS are becoming a viable remote control and data receiver/sender. We’ll see plenty of hacks like this.

  6. Bonzi says:

    i know that the palm treo can open lock boxes for realtors, i suppose soon they will open your garage door as well….

  7. Boudico says:

    #5: probably not all that farfetched of an idea. Though not sure about the stove in particular. But there are already IR controllers for lights/etc. Seems like it would be a short step to send the signal.
    Good stuff!

  8. raver1975 says:

    There are all ready programs out for cell phones that will control your home computer like you were sitting in front of it. I wrote one in Java myself. This was two years ago.

  9. Roger Jollie says:

    The more things change, the more they remain the same. I rememeber seeing a project similar to this many years ago. It used the x10 home automation telephone decoder and appliance modules to control a solenoid door strike. If you lost/forgot your keys you simply called the automation from a neighbor’s house or pay phone, turned on the particular module and the door unlocked. This was well before cell phones were widely known and before most people had answering machines.

  10. tom says:

    #2, this kind of applications has been for sale for years, so this brings nothing new or worth of patenting.

  11. hank says:

    thats what terrorists use to blow up car bombs etc remotely

  12. Jeff says:


    My buddy Ray already has the patent on that, #5.

  13. jerm says:

    For all you college students out there who have in-dorm landlines but never use them, just hook this up to your landline phone instead of a cellphone. Call your dorm to unlock the door, and you don’t have to worry about wasting a cell phone.

  14. tom says:

    in israel we have that as a product for apartment houses to open the front gate. It recognizes your caller ID so it can be narrowed down to a few users.
    much more convenient than a remote , which you have to carry around anyway..

  15. Mike Clayton says:

    Great project! Especially for every roadside bomber wannabe

  16. srilyk says:

    How many of you have ever used those voice activated menus? The one for the US Post Office never worked for me until I started calling it all sorts of dirty names. Then it worked great.

    That sure would be fun to hack as an add-on to this… “Open the **** **** door you ****!”

  17. DoctordD says:

    The terror boys in Baghdad have been doing this for years. Of course, they aren’t unlocking doors when they dial their cell phones — just blowing them up!

  18. Wolf says:

    Thats just what I was thinking #15

  19. ejonesss says:

    a hacker would not even have to brute force it if the lock picks up the tones let out loud by the phone just hide a recorder to capture the tones

  20. def says:

    Nice to see you posting real hacks again rather than wanking over Ben Heck.

  21. Mike says:

    Phreaking will live again?

  22. Seth says:

    Just check out Homeseer.com #5 and #12. It allows me to send a text message (or use DTMF tones or speak a command) to open my front door. I can also just walk up to the door and it recognizes my bluetooth signature and opens the door when I depress the doorbell button (which doesn’t ring inside in that instance).

  23. lloyd says:

    IED makers all over the world love you.

  24. map says:

    Hey everybody…
    a friend of mine recently bought for a few euro (i think he bought 10 if this for 60 euro) a gsm unit (not properly a cell phone), that is old model from Ericsson and it has external connector for power,antenna,audio and serial!!! it’s cool, easy to implement something with it, since sim cards are so cheap, u could just use it to controll the door or heating or whatever…

  25. Jasper says:

    Why not use a simple phototransistor that starts conducting when the backlight goes on. Then you don’t need a DTMF decoder!

  26. Long Nguyen says:

    The idea is good, but security is low. Someone can record your DTMF tone and open the door.

  27. AnanD says:

    wow this the gretest thing in the whole world…….zapppppp…

  28. Chuck says:

    This sort of thing has been used by ham radio operators for remote control of radio systems for about 40 years. Before cell phones they used hand held radios and a device called a tone decoder for autopatch (remote control of telephones).

  29. Ivan L. says:

    I now know what to do with my old cell phone. I thought I was going to have to recycle it. Door opener, here I come.

  30. Insteon says:

    Paying the monthly subscription fees for another cell phone just to use it as a lock seems kinda excessive. Then again this is “hack” a day and not “practical living solution” a day.

  31. Felix Kikaya says:

    Does this only work with Nokia 1100 or does it work with other phones too. I have a similar circuit, but it is not working at all.

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