Ever get the feeling that your door is unlocked?

  • Thread starter inutard
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In summary: Taser and a knife.)In summary, this guy thinks of a way to make a device that checks if your door is locked or not. He thinks of ways to make the device simple to install and make, and he also thinks of ways to make sure that the device is not intrusive.
  • #1
inutard
93
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Hey guys!

I've just thought of a neat idea for a summer project, and I'm requesting some opinions on its usefulness and feasibility.

For a forgetful guy like me, I always get the feeling (while I'm walking on the streets) that my door is unlocked. So today I was thinking about how to make a device that checks if your door is locked or not. After a minute or so, I thought of a basic design: An accelerometer that is connected to a wireless transmitter (since most doors are deadbolts and require turning the lock to different orientations to lock them). This way, all you would have to do is to stick a non-intrusive modified accelerometer onto your lock!

So what do you guys think? Possible issues (Range problem)? Possible solutions to possible issues (making the signal send to a wifi network and uploading the status of your door online)? Ways to design such a device?
 
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  • #2
Bear in mind the different motions you could potentially need measure. If it's a deadbolt moving in translation, will an accelerometer tell you anything about its position when not in motion? If it's a handle or lock barrel rotating into position, actuating the bolt, can you use a bi-axial (or tri-axial, they're not significantly more expensive) accelerometer or gyroscope to measure the rotation instead?

Also, before you go that far, you could try thinking about more simple sensors. Tilt switches and limit switches (especially) spring to mind. A binary sensor which tells you whether your door is locked or not depending on whether the deadbolt has traveled past a switch would be a very simple solution. Not sure you'd want your house's security resting on it though ;)

Finally, there are a number of solutions to access your sensor state remotely. Some make little sense (as you suggested, the range problem) but updating a status via the internet is probably a feasible option. For instance, I write pieces of software that run via a webserver, which I can log on to remotely regardless of connection method to check on the status of my experiments.

Try looking at LabVIEW and running a webserver through that. It's a pretty simple way of achieving what you're after without too much need of coding experience too.
 
  • #3
You non't need accelerometers. Although, that idea is being used by a sensor I have on my garage door. It signals a receiver in the house to light a red or green light depending on the position of the door.

Simple contacts or limit switches are all you need.
 
  • #4
Great suggestions! But the reason I wanted to use an accelerometer was because it is easy to attach and very non-intrusive. One of my goals for this device is for it to be as simple to install and make as possible. What could I use if not an accelerometer?
 
  • #5
Might I suggest medicinal treatment for your OCD?
This is not a flippant response. I have a touch of compulsion as a nasty tag-along to my ADD, and the medication helps a lot.
I am not a medical professional, and even if I were we do not advocate any form of treatment on PF. I merely suggest that perhaps you could consult your physician to investigate whether or not this particular worry of yours is a symptom of a psychological condition. (Even with my meds, I still check my pockets at least 3 times before I leave the house to make sure that I have my keys to get back in.)
 
  • #6
I'm similar although I don't consider it to be OCD. I associate that with people who wash their hands 40 times a day and need to take 12 steps from the couch to the bathroom.

I simply like to make sure that my door is locked, that's about all. It probably stems from getting robbed twice in college, but because of that, I consider it a worthy cause to check the doors when I up in the middle of the night going potty.
 
  • #7
minger said:
I'm similar although I don't consider it to be OCD.

But once clear of the house, your worry is left behind? That is where I see a difference.
 
  • #8
I'm usually not too concerned when I'm away from the house. It's when I'm in the house that I'm concerned. I'm concerned for what a criminal could do to me or my room mates, or what I would do to them.
 
  • #9
That's simply common sense. Just make sure that you put more concern toward what they might do to you than what you might do to them. When in doubt, go for the pre-emptive strike. As I always say, I'd rather spend the rest of my life in jail than the rest of forever dead. (This is based upon the assumption that you are very good with whatever your weapons of choice are. If you aren't, then hide somewhere and call 911. That should be your first action anyhow, as long as you have time and access to a phone.)
 
  • #10
Lol. Gentlemen. Whatever is this discussion going? This is the engineering and design forum is it not? I am just looking for some ideas and some inspiration for what I think is a worthwhile project.
 
  • #11
Might I suggest something a bit simpler? How about a contact switch or similar and a short-range signal to a key-fob or similar? You set the lock as you are leaving, and later when you start to doubt yourself, you check the fob on your key-chain to see if the red (locked) LED is illuminated or if the green (unlocked) LED is illuminated. No problems with range, timing, etc. Latch that sucker and get some peace of mind.

BTW, if you sell this idea to Ron Popiel, and don't cut me in, I will hunt you down like a dog.
 
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  • #12
Have a simple switch on the inside of the door frame where the dead bolt enters. When the deadbolt is locked, or pushed into position, it will depress a button, which would in turn update a twitter status, telling you that your door is locked. You could set it up to update say every hour or so.
 
  • #13
inutard said:
Lol. Gentlemen. Whatever is this discussion going? This is the engineering and design forum is it not? I am just looking for some ideas and some inspiration for what I think is a worthwhile project.

Sorry, Inutard. I owned a security company for 17 years, so I tend toward maximum survival of the client. I didn't realize that you had a specific electronic plan in mind. :redface:
 
  • #14
Another approach would fall under the KISS principle. Figure out a routine where you basically have to lock the door to be able to leave. Something as simple as hanging the keys on the deadbolt knob inside the door, and making a point of taking the keys off the knob and locking the door right as you leave. Then put the keys in a pocket (or on one of those handy belt snap hooks that I started using a while back), and make a point of patting the keys as you start walking away from the door.

Or something similar. For example, there are disk brake locks that some motorcyclists use to lock up their front wheel so their bike can't be "roll-away" stolen. Problem is that it is pretty easy to forget that you have locked your front wheel, and there is a risk that you will get on your bike and try to ride away. It's not a very long ride. Not that it's happened to me or anything; I'm just saying. So a very clever solution is offered as an after market addition to disk locks -- it's a bright orange coily cord thing that runs from the disk lock up to the ignition keyhole. You have to remove the keyhole end to start the bike, and that's your visual reminder to remove the disk lock. Remove before flight!
 
  • #15
I like that idea. Just like the wallet problem, where no matter how sure I am I have my wallet, I will always check that it is there every 10 minutes or so. Same principle as the key idea, or the orange coily cord.
 
  • #16
Cool idea, Berkeman.
It's sort of like why I have the chuck key for my electric drill fastened to the plug end of the power cord; I have to unplug the thing before changing bits. It's a pain in the ***, but it's probably saved me from a lot of injuries.
 
  • #17
Lol danger its ok. I forgive you :)

@turbo-1 I also thought of that idea. But think i started wondering what would happen if i forgot to set the switch... Lol (Set it and Forget It!). But i do like the immediate signalling to the fob tho. If i keep the accelerometer, i can just have it immediately signal some indicator on my keychain when i lock the door from the outside! That would eliminate the range problem =P

@MotoH How hard would that switch be to install though?

@berkeman Yeah I was doing something similar to that. But sometimes I lose my cord... :(
 
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  • #18
Well I am not an engineer of any sort, but drilling a hole on the inside of the door frame so the small switch fits, which can be extremely small, because all they have to do is complete a circuit. Run the wires from there to a module that can connect to a computer and run a specific set of operations (this is where it gets fuzzy because I am definitely not a programmer!) But I have seen homemade devices that update to twitter before, so it shouldn't be that expensive or technical.
 
  • #19
Why not just use commercial locks that ALWAYS lock from the outside(without a key) but from the inside you can simply turn the knob/handle/etc and get out?
Very available. Problem solved. Sleep tight. ZZZZzzzzzzzzz
 
  • #20
Simply because I would have to change my lock and that would constitute as an 'intrusive' change that requires more effort. Besides, this is a summer project of mine, so just changing the lock wouldn't do it for me.
 
  • #21
inutard said:
Simply because I would have to change my lock and that would constitute as an 'intrusive' change that requires more effort. Besides, this is a summer project of mine, so just changing the lock wouldn't do it for me.

Ah, yes, projects! I know what you mean.
Seriously, I'm not being sarcastic at all. I love projects.
Carry on!
 
  • #22
This sounds like a cool project! keep us updated.
 

1. What does it mean if I have a feeling that my door is unlocked?

Having a feeling that your door is unlocked could mean that you are uncertain or unsure about the current state of your door. It could also indicate a sense of vulnerability or anxiety about the security of your home.

2. Is it common to have a feeling that my door is unlocked?

While it is not uncommon to have a feeling that your door is unlocked, it is important to address this feeling and ensure the safety and security of your home. It is always better to be safe than sorry and double check that your door is indeed locked.

3. What should I do if I have a feeling that my door is unlocked?

If you have a feeling that your door is unlocked, it is important to act on that feeling and check your door. Make sure to physically check that the door is locked and secure before leaving your home or going to bed.

4. Can a feeling that my door is unlocked be a sign of a larger issue?

In some cases, a feeling that your door is unlocked could be a sign of anxiety or stress. However, it could also be a sign of a faulty lock or a door that is not properly closed. If you frequently have this feeling, it may be worth investigating the cause and addressing any underlying issues.

5. How can I prevent the feeling that my door is unlocked?

The best way to prevent this feeling is to double check that your door is locked before leaving your home or going to bed. You can also install a security system or smart lock that allows you to remotely check the status of your door and ensure it is locked.

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