Help Billfred Outdo a Prankster and Win a Prize!

Alright, here’s the tale…

I live in a University residence hall. 200-something people, and I’m on the first floor. Right by the stairwell, so I’m a frequent victim of the ding-dong-dash. (More specifically, people bang on my door and run up the stairwell, thus evading their doom since I can’t get to the door fast enough to see them.)

However, I see an opportunity to level the playing field. Over spring break, University Housing is installing peepholes in every door in the building. It doesn’t seem too hard, IMHO, to use this newfound resource to catch the person(s) doing it. Problem is, I just don’t know how to do it.

With that, I have the requirements:

[li]Through any method of the designer’s choice, the device must be able to record an image of a person through the peephole while a banging is in progress. [/li][list]
[li]“Black Boxes,” which record the last X seconds of motion, are permissible, provided they record at least the prior 60 seconds. [/li][/ul]
[li]The device, once built, may not require any modification to the door, and it must be removable from the door without any marks or damage to the door. (This keeps Housing happy.) [/li][li]The device must be affordable, meaning it would cost me under, say, $50 in equipment. [/li][ul]
[li]I have the following equipment, which is fair game: a Pentium II computer running Windows ME (don’t ask), a USB web cam, miscellaneous junk that would be found in a college student’s room. [/li][/ul]
[li]Once installed, I must be able to still use the door. [/li][/list] What does the winning design get? Definitely a good rep click, probably a button if I see them, and perhaps some Krispy Kremes if we meet at a competition. (Delivered off-site, of course.)

I’ll be very interested to see what the group comes up with.

I’m a mechanical engineering student, so I’ll comment on the mechanical side of things. 3M’s Command strips would be perfect for mounting the device, as they can hold a great deal of weight, and can be easily removed without damaging paint or leaving any sort of residue.

Maybe you could rig up a cheap web cam to look through the peep hole in the door. This might not work if your computer is all the way on the other side of the room, but it’s an idea.

I have a web cam set up on my desk in my dorm room that points towards the door. I have it turned on when i leave the room to go to the restroom or just any general time so I can see who is at the door, since I face away from the door while sitting at my desk. It is motion sensitive and it even has a setting so only motion in a certain portion of the display is detected. It either does snap shots or video and can be saved on the hard drive or emailed to an email address.

EDIT: I just thought of this and it’s kinda funny. You could remove the peep hole once installed and place some kinda of tube in the hole of similar size. You could then run the tube to where ever you sit and at the end of the tube have one of the “squeezy rubber ball thingies” (I can’t remember what it’s called for some reason but hopefully you are following me). You could then fill the ball and 1/2 the tube up with some kinda of non-toxic ink and whenever you hear the door knock you could squeeze the ball, forcing the ink through and out the tube, and cover the individual(s) outside the door in ink (hoping that it’s not really one of your friends coming over to visit). Then you could easily identify the pranksters. :slight_smile:

Can you show us a picture of atleast the door and the area around? if possible a picture of the room too?? A good idea is wireless cams for like $20. They’re of very poor quality, but if it works for you good then. Maybe pics of the place can give us a few nasty ideas…

Heres another inexpensive idea… I don’t know how possible it is though…
You know in schools how if you pull a fire alarm it leaves a paint mark or something on your hands… you could use that… and pray that the person doing some “bing bong” on your door isnt smart enough to wear gloves…:stuck_out_tongue:

just duct tape the webcam to the peephole and plug it in to a computer with the software.

I’m not going to try to come up with a good idea for the webcam… but I do have an interesting idea to get back at them. :slight_smile: A friend of mine attends college up in Northern Florida and one of the people on his floor always had people bugging him with things, and he pretty much wired up a 12volt (I think) battery to the metal knocker on the door… so when people would knock on the door, they received a very unexpected “shock” hehe… they quickly stopped knocking on his door. :slight_smile:

Well, off hand, I’d do it with a Logitech QuickCam Express (i.e. the original cue ball webcam), since its cyclopean eye is staring back from the top of my monitor, as I type.

Fortunately for you, you have a PII, which can handle the camera, provided that it has USB. (This shouldn’t be too difficult to add, if it has a built-in header, or any PCI slots available.)

Logitech has an SDK* for this, allowing camera objects to be embedded as ActiveX controls in programs. I’ve done it with an older version of the SDK and a Delphi 6 program–but that was a couple of years ago, in high school. With a little work, I think that it’s possible to record an uncompressed video stream to a file. It would then be a matter of creating a new file every few minutes, and deleting the oldest one (so that you have several consecutive minutes of “tape” before deleting any).

If that’s too much (because you’d need SDK reference to figure that out easily), then Media (finally a new version– has the option to record video (and sound). In fact, I can get 10 frames per second at 640 × 480, or 15 frames per second at 320 × 240 (or several other low resolutions). Depending on the compression options, it may be possible to record enough in one go to last several hours. Don’t try this uncompressed, though–I just got 23 MB per second… Recording as an .avi with DivX compression, and with a brief adjustment of settings, I got a half-decent 1 min video that only used 348 KB. Since it will stare at an empty hallway most of the time, the bitrate will be low until a victim crosses its path. You can even store hours of video on a small hard drive, this way.

And if you’re wondering whether it will shoot through a peephole, well, I am too. But it works just fine through a 1 cm hole at short range–see attached.

So, in summary, the absolute-cleanest way would be to code a program. The easiest is to use Media Player Classic. Tape the camera to a cardboard frame, stick the frame to the door using your choice of removable tape (at Waterloo, we get a sheet of “Magic Removable Mounts”–these are good). Plug it in and run it. When you hear the evil knocking, simply stop the recording, and cue through it to the appropriate time. Now that I think of it, the old-style QuickCam Express has a 1/4-20 thread for a tripod–you could even mount it elegantly to a bracket. No big deal for a robotics-person.]

Now who says mechanical engineering students can’t come up with good ideas involving lots of software? And yes, I know that I take too long to compose posts, and therefore many, many people got in ahead of me.

*This may not work! I haven’t tried this version of the SDK, only an older one.



I’m looking at MPC right now, but I can’t seem to find the recording option. Where would it be?

Go to File | Open Device, then select the webcam (if you have one) from the list. (Sound is also selected there.) Then go to View | Capture to bring up the video capture toolbar.

Use the … button to select a file location, and the other options ought to be reasonably self-explanatory. The Play button will start the video capture, but the Record button will actually start saving it to disk.

Edit: I’m using the NT4/2000/XP/2003 version of MPC–I can’t say whether for 95/98/Me will work quite the same way. But I don’t think that that’s the problem; merely the fact that the video capture option is hidden.]

Just tape this camera to the back of your door and then plug the reciver into your tv or vcr to record. its a bit more than your budget but i think it could make due. its only $99 at your local radio shack.

What about some premade webcam motion detector software?

Not free, but the demo should let you know if it will work or not, hit up google and search for “Webcam motion detection” for more possibilities, I tried searching for some free stuff for ya, but its all shareware :frowning:

Put a sign on your door that says “All knockers are being recorded” :smiley: :smiley:

If they know, they may just sneak around the peep-hole, because those things can’t see everywhere in front of the door. Someone could easily get low enough to evade peep-hole detection and continue the ding-dong-ditch game. If they don’t know that they are being recorded, then they will continue their antics and be caught more easily.

!more easily

I was afraid to see something to do with Dave, and was not even going to read this, but decided to be daring.


can we have more data? do you have any guesses on the diameter of the peep hole?

As for mounting, (if you do a camera) unless your door is a very close fit along the top I would take a simple very thin strip of metal and bend it up and over the top of the door so the tip comes down the outside (just a centimeter or so).

Personally though I think getting a reputation for hunting people down isn’t the way to go. I like direct smiting :slight_smile:

Cover your door with plastic wrap. It makes it easier to clean. Tack very full bags of liquid to your door. Water is good because if you don’t clean it up nobody will notice. “Decorate” door with an offsetted cardboard structure hiding the bags. Tissue paper will work well because it will not stop the water from spraying.

If people are really pounding hard on your door they should get at least something on them.

If you actually can remove the peephole from your room put a small tube in. Put a spring in the back and stick junk in the tube then a lid on the front of it. Offset the actual front of the door again so that when the fake front is pressed down it pulls the front of the tube open. You could also have it just release the spring and always have the front open.

Offset the front of the door with a thin metal plate. Pressing the two together makes a connection to a circuit with a small battery (inside) so that they get mildly zapped. Your might want to connect a speaker into the system so somebody doesn’t get you back by short-circuiting/heating up your door.

Offset the front of the door with something that can be easily broken. Put pointy objects on the real door.

never drying paint on the door… then you wont get anyone do it ever, and maybe put a secluded door bell so that they can ring you if they are real…

put…like a shoe out side your door (and tell house keeping not to move the shoe) put a camra in there and …see what happends :slight_smile:

Once you find out who they are… try this:

Make sure that the perpetrator is inside their room.

Use duct tape and saran wrap to cover their entire door - from side to side and all of the way to the bottom. Leave a 1 foot gap on top. Pop a bunch of popcorn and fill this “pocket” entirely.

Poke a stick through the pocket and knock on the door.

Stand back.



Good luck,

ps… beware, as this may cause the perpetrator to get back at you again. Don’t blame me.

My method is probably unrealistic, seeing as it’s untested and I just thought of it ten seconds ago, but here goes: if you run poinson ivy on something, then the oil that causes the painful rash rubs off. You could, in theory, coat your entire door in this substance, thus giving them a nasty surprise when they come a-knocking.

Why not just remove the door and then you dont have to worry about anyone knocking :slight_smile:

no popcorn…packing peanuts…popcorn is good to eat…

As a side note if you know how the power/fuse boxes run you can always take out the power for one fuse…run two hairdryers from the same socket…

I have also heard of an art of sticking pennies in doors to make them not open…

If you can get some help from the person in the dorm directly above your victim it is awesome fun to lower things outside the window.