Door Knocker


(Nick Meyer) #1

I tired to set up the Door Knock app last night and did not seem to do anything. I have it set to my front door which has a SmartSense Multi So it states…

When someone knocks
Where? Front Door

But not when they open this door?
Where? Front Door

Knock delay.
I left blank for the default to 5s

and to send me a push notification.

But nothing happen when I tested it. Not even in the activity feed. Am I missing something?

Nick


KNOCKI - New Device Spotted... Thoughts?
(Jeffrey Denning) #2

Did you put the Multi itself on the door or only the magnet?
Also, does the sensor report open/ close actions?


(Nick Meyer) #3

I put the bigger side on the door. It does see the open/close.


(fightingmajor) #4

I’ve tried getting this to work before as well and could not get it to work.


#5

I’ve had almost no luck with the door knock smartapp either. I can knock on my door softly, loudly … from inside … from outside … it doesn’t seem to alert.

And then the Domino’s pizza guy came one night and knocked … and it triggered.

I’m baffled as to what the secret is … but for the most part, I assume it’s more or less useless as a SmartApp for now.


#6

The problem with door knock detection is that the acoustics vary so much from door to door it can be very difficult to get it right.

Lockitron had a knock detector on their first generation lock and dropped it for the second because it was just too tricky.

http://help.lockitron.com/article/95-whats-bolt-and-how-will-my-lockitron-order-change

Removed Knock Sensor

We found that certain doors would trigger the knock sensor too easily, thus keeping the crowdfunded Lockitron awake and draining batteries while other doors would require significant knocking before the sensor triggered. The knock sensor functionality in the crowdfunded Lockitron requires a very special, low-power electronics circuit that is not adjustable in the field. Given that we already set our knock sensor to be as sensitive as possible, we decided that we unfortunately cannot offer consistent knock sensing capabilities and are removing this feature for now.

If it works for you, great, but if it doesn’t, it’s not surprising.

A more consistently reliable option for visitor detection is a smart Welcome Mat. :blush:


#7

Is it an acoustic sensor? I thought it was a vibration sensor or accelerometer…

If I open up the “thing” in the SmartThing app and just tap lightly on the main body of the sensor (the part stuck to the actual door) with my fingernail … I can see it trigger into “activity” mode … so it’s sensitive enough to detect that. If that activity is detected, and then the door isn’t opened 10-15s later … I’d think it would alert and say “Someone is knocking at the door” … but that doesn’t seem to be the case.


#8

Sound is vibration. The original application of the science of acoustics was to the measurement of mechanical vibration.


(Bruce) #10

Then there is this very cool Arduino based secret door knock lock opener:

http://grathio.com/2009/11/secret_knock_detecting_door_lock/


#11

Given that I can’t yell at the multisensor and have it detect “activity” … I’m not really sure that subtle nuances between the finer points of sound/vibration/acceleration … have any real practical relevance here?

Simply put, it doesn’t work consistently. That’s ok - it’s not the end of the world if that feature doesn’t work. I was just trying to figure out here if it was just something I was doing on my end. So far, it doesn’t seem like that’s the case.


#12

The “acoustics” in this context mean the vibration pattern through the material of the door, which is what’s being detected.

Where the person knocks, how hard they knock, how fast they knock, the humidity and temperature on that day at that moment in time, all affect the vibration pattern. Plus the fact that different doors and door frames are made of different materials.

Remember that the knock is usually on the opposite side of the door from the sensor. That increases the number of variations you can get as well.

It’s pretty easy to set up a sensor that will catch some knocks some times. Really hard to set one up that will catch only the particular pattern you want and not false trigger for anything else.

OTOH, a smart welcome mat with a pressure mat underneath it will catch most visitors 25 pounds and up with very few false triggers. (They may miss visitors in wheelchairs unless you use a very thin mat and move the mat further back from the door.) They’re basically the same physics as a push button door bell.


(Nick Meyer) #13

Thanks guys. It seems to be picking up the knocks much better now but maybe that is because it is warmer out.


(Kevin O'Donnell ) #14

So my sensor picks up knocks fine, too fine. It actually detects knocks when nothing happened to the door at all. It just randomly says a knock has been detected. I have survalence cameras so I can check. Maybe air pressure differences causing my door to move is causing issues? Anyone else having issues receiving false knocks? I’m going to switch sensors with another door and see if that fixes the issue.


(Bobby Thompson) #15

Probably not much help but mine has worked quite well since first setup.

I placed it about 1.5’ from the top open end of the door. aI figured it was close to the knock point and should get some shake…

My biggest problem is by the time I get the alert I don’t have enough time to reach the door before they leave…


(JimmyS) #16

Too bad the app doesn’t let you use an audio notification. Then you could have a doorbell with your fist. Hint, hint…


(Vinicius Watson) #17

Where can I find that Door Knocker app? I dont see it inside smartthings

Thanks