'Secret Knock' Door Lock defends home from rhythmically-impaired perps (video)
By Joseph L. Flatley 
posted Nov 4th 2009 8:14PM
posted Nov 4th 2009 8:14PM
The Arduino board has been the engine of many wild and wacky projects over the years, from bakery tweeting to various musical instruments. For its next trick, our man Steve Hoefer has taken his microcontroller and, along with a piezoelectric speaker, a gear reduction motor, and some PVC pipe, programmed it to listen for a preset sequence of knocks -- a secret knock, if you will -- and unlock the deadbolt upon hearing the right combination. Although this might not be the security system you want to put in place for your home, this definitely looks like a fun weekend project. Check out the read link for instructions and schematics, but not before you see the video of the thing in action. It's after the break.
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Awesome
You said it, man. THIS is innovation. Seriously
and everyone else is all wacky over multitouch...
It will be henceforth known as:
Knock Lock (tm)
oh, how i love Arduino!
I got back from work and found my door all knocked up.
I'm a door, and the 'Secret Knock' Door Lock was my idea.
hahaha. Took me a second to get the reference.
This looks fun although if someone hears it once your secret stash is pretty much compromised.
Knock knock who's there jokes goes here ...
this is why i love arduino; its like a festivus for the rest of us
I see what you did there...
alright keys im happy for ya and im gonna let you finish, but secret knock detecting lock had one of the best door unlockers of all time
engadget ban this person plz... im very offended
Get over it.
i'm kinda tired of that joke, but seriously, using that word, ESPECIALLY in that context, is NOT ok.
Want
It brings new meaning to port knocking.
When I first saw the three feet, I thought it detects the location of the knocks. Like an invisible numpad.
Now that would be awesome
Love that project.
What if you lose your arms, and after being in the hospital for six weeks come home to this? Guess you can always bang your head against the door.
If you lost your arms I think trying to knock on the door would be the least of your worries. Let alone how the hell would you unlock your door with keys with no arms?
"Special" agent, indeed.
My giant dong opens any door.
If by 'door' you mean your boyfriends pants, then yes.
Hrm.. gays are normally pretty tolerant about jokes, but they might actually find you putting him in their category (even for a laugh) offensive.
also: giant in internet inches = 2cm. you can't knock with an innie, stupid.
Incredible idea, unless there is a woodpecker in your back yard.
I can't wait for the Ministry of Silly Walks theft deterrent system...
http://www.youtube.com/watch?v=IqhlQfXUk7w
Wait, so that one knock is called "shave and haircut"? really? alright, something I didn't know there.
You haven't seen Who Framed Roger Rabbit.
the words go:
shave.and-a-hair.cut.....two.bits
oh man, its been a very long time since I have seen that movie. I wouldn't remember.
http://en.wikipedia.org/wiki/Shave_and_a_Haircut
Best DIY gadget ever!
I have a clapper version of this device.
This is a must for that secret panel in your wall where you don't want handles to show! genius!
ahh man, i was thinking the same thing!
Exactly my thought too!
FBI knocking on your door? No problem. Run to secret wall, knock, knock-knock, knock, and *bam* wall opens to your secret hideaway.
I'm surprised nobody commented on how you can't get in the door if your battery runs out. :)
You can still use the key.
Yes, I'm assuming the motor will turn without damage if the battery fails, allowing you just to use the good ol' tumbler device :P
Don't use the Terminator theme. It's too catchy. *tap,tap...TAP...tap,tap*
So, everytime you bring someone home, you have to say "wait a minute, put on your earmuffs and close your eyes" so you can unlock your door? Brilliant.
This one is inferior to the real one...the real one you can "enter" as many digits before you start to enter the real code, so you can enter 100 'digits' before entering the up to 6 digit code. Or just enough to confuse anyone who might be listening.
Ahhh! endless jokes about drummers spring to mind!
Man...this kills my idea of a Laser that kills people that don't get the combo right.
I guess I got Kanye'd.
http://www.nokey.com/knocknoctoac.html
Knock locks have been available for over 7 years now (that's just the time I vaguely remember considering one anyway)......just need an electronic strike.
Is this news?
You must be new.
lol@ dzi. so true.
Metro: I agree - This would make a great secret entrance to a top secret secret lair/lab!
I dont know about for the front door of my apartment, but maybe for like bedroom or something like that lol.
Yeah, I'm sure you have a problem with all the people trying to get into your bedroom.
Maybe to keep them IN the bedroom...
sadly ur neighbor will hear it so its best if theres a voice recognition so no one can ever immitate u.
even still, voice recording? I think probably the biometric scanner would be best bet, although that would mean whoever really wants in is going to slice off an appendage...bummer.
If my neighbor heard me knocking on my door, they'd think that I had guests, not that I was unlocking my door with a secret knock....
Just don't tell your goddam neighbors.
Intersperse decoy knocks on the other side of the door maybe?
Say I run to the 7-11 without my key. I come back, and it has fallen off because it's held on with SUCTION CUPS!
What then?
I suppose you could make a variant that screws in...
"Open, sez me!"
So white guys and Jews* won't be able to open doors with these locks on them??
*South Park reference, don't get offended.
id set it to the knock pee wee does on Francis Bucktons door.
I'd program it to the beat of "match in the gas-tank, boom boom." no one would guess that in a Million years!
Wow Arduino's are actually cool. I always thought they were only cheap things schools used.
Pretty awesome stuff, and and aside from the DIY looks, seems pretty polished and working flawlessly ! Kudos, you sir.
This said, as a sidenote, why why why why can't people say piezo correctly ? Peh-eezio ? Really man ? :P
that is very cool. like very much.
let's just hope he doesn't come home one of these and forgets his secret knock by some odd chance.
Genius!
I should try something simple like the drum solo to "Stairway To Heaven".
Nice work! I can see this being useful in contained environments. E.g. when we had a computer room setup this would have been ideal. It was in a long hall and the door had a key lock on it. But if we had this it'd be so much cooler.
This is brilliant - I am now about to purchase the Arduino mega due to this guy's genius.
I have previously built MIDI gloves using the I2C bus and a philips microcontroller: midair.info (apologies for the splash video) and this has inspired me to do more work and come up with more ideas
I think this could be a great idea but not like how its being use to unlock the door. I have no problem unlocking my door with my key but locking the deadbolt with my key is a different story all together if i could just shut my door and do a knock to lock it instead of have to lock it with me key now thats a different story all together.