Keyless entry via SMS

[Billy's] work got new keys which he didn’t want to carry around with him. Instead he built this system to unlock the door via text message. It is based around a Spinneret Web Server which drives a servo motor. He’s rigged up a pipe hanger to add some leverage to the lock’s knob. We’re surprised that the servo has enough power to do the job here but the video after the break shows there’s really no problem. On the communication side of things [Billy] set up Twilio to wait for text messages from an approved list of senders, then used an HTML form to issue the unlock commands to the webserver.

[via Make]


  1. Aaron says:

    Hey, awesome! And if you use an MVNO as shitty as mine, you can text the door and stand around half an hour waiting for it to unlock!

  2. GotNoTime says:

    Huh. I’m surprised that the little servo has enough torque to turn the lock as well.

    The SMS whitelist doesn’t give you amazing protection though. There are sites online which let you spoof a SMS and type in whatever you want as the sender. I guess you’ve got bigger problems though if somebody knows you well enough to know your cell number, your door lock cell number, how to operate it and is malicious :)

  3. Dan says:

    Hope he has a backup power unit just in case the power goes out and he leaves his keys at home.

  4. Olek says:

    For me it is interesting, if it is possible to “override” the servo with the plain old mechanic key if the system would (for some reason) went mad?

  5. Amperand says:

    This is awesome. I want one. Or 12.

  6. aztraph says:

    not much on security. keep it lan enabled and a wireless router would be more secure, and keep your friends from unlocking your door in the middle of the night or while your away, bad way to get punked.

  7. Fallen says:

    I’m surprised that servo has enough torque to lock the door. I kind of want to see a vid with it actually unlocking the door. When it’s like this there isn’t as much binding on the bolts of the lock.

  8. jeff says:

    It’s not like the servo is connected directly to the knob.

    There is a lever attached to it.

    Notice how the servo horn turns a bit more than the knob.

  9. jimmys says:

    Is that a few copper strips bearing the load of the high-torque servo?

  10. yosh says:

    Parallax seems to be holding a Spinneret design competition with $3000 as first prize

  11. Richard says:

    Is it possible to spoof the phone number in a text messg? I.e. an attacker could send a sms with a false header saying it was from billys phone? shouldn’t he use some sort of encryption/ handshaking


  12. gilbert wham says:

    @Olek. Yes, you can turn the tumblers and the inside handle on these locks independently. And I love the fact that HAD’s comentariat’s first thought is, ‘How do we break into this dude’s house?’. Splendid.

  13. Entropia says:

    Whoa. How overly complicated can you make a system? Quite much apparently.

    How about just using a $25 GSM modem from DealExtreme mated to an AVR? Total BOM cost $30 and two potentially failing steps eliminated from the chain of opening the door.

  14. Cricri says:

    So to avoid carrying a key that unlocks your door instantly, you need to have your phone (not only can you lose it like your keys, but you are more likely to have your phone stolen than your keys, it can run out of battery, you can have poor coverage, the lock is not aesthetically pleasing, consumes energy, it can run out of electricity say if there’s a power cut, …), type and send a text message, and wait (see unlocking in the video) for your device to receive the text before you can get in or out?
    Yet another hack making a fine and perfected solution less practical, just like a binary clock.

  15. efren says:

    i would like to know how the device detects that the door is actually closed? or if there were mechanical failures, will it still reply “door closed” even the mechanical lock malfunctions? thanks for the help Mike

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