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Home Made Alarm Systems?
screwBrinks! asks: "I would like to begin a new project to do during those long and boring weekends. I thought about creating an alarm system in my apartment which would be connected to my computer. Then, if there is any intrusion, it would page me or phone me. I also want to be able to see a live report from the web and some other goodies. I have no problem doing the software part, but I don't have much experience with building hardware. Have any of you ever built such a system? If so, what would be your recommendation? I know much of this may already exist prebuilt, but I really would like to make as much of it as I can, for fun. I have no problem against using prebuilt infrared detectors, prebuilt door contacts, and the like as long as they aren't X-10 products."
I know somebody who did this recently. The results are very impressive, and he managed to do it all very cheaply.
First step was picking up a mini-security camera from the local electronics store. Cost $150AUD and is the size of a bottle cap. It's a CCD based camera with 12V input and standard TV composite output. It uses a pinhole instead of a lens to get the size so small. It's only black/white but it also picks up infrared! Auto-adjusting brightness. The picture quality is quite amazing.
Run a coaxial cable + 12V power cable (low amp wire) to the camera. The cable can be really long - this guy is running it over 20 metres. Plug the other end of the coaxial cable into a BT878 TV card on the PC. The TV card was $100AUD. The PC was $300AUD. You need at least a Celeron-2 processor. The 12V power supply is $20AUD pre-built from the electronics store.
Next, install Linux! You need the "motion" software package. It records MJPEG (?) but only records changing frames. It also puts a useful highlighted rectangle around the section of the frame that moved.
Finally (and I don't think he's done this step) you write a simple script to rsync the motion/MJPEG output directory to a remote server. You can use "stat" on the directory to determine if there are new frames: record the "modified" line, compare it on subsequent stat commands, any difference means there are new frames so call rsync! You could easily stick an email in there as well to alert somebody.
The setup is very impressive. The picture quality is simply incredible. Because the CCD camera detects IR you could even use it in the dark with some IR leds to illuminate the room with "invisible light". A number of people have shown interest in building their own after hearing/seeing about the original setup.
Tools:
1. extension cord
2. two big metal trash cans.
Method:
1. Cut end off of extension cord.
2. Strip cord
3. Split wires
4. Connect one wire to each trash can
5. Place right behind your front door, but not touching.
6. For extra effect, put something expensive at the bottom of the cans.
7. Plug in.
8. Not for use around ferrets.
I found this a while ago. This connects to your printer port and supports 5 zones. The electronic hardware is quite easy to build (I've built simmalar things). You could also modify it to provide home automation.
I'm imagining a bucket of water precariously balanced above the door, with a string leading to the power switch of an amplifier, whose input is a microphone sitting directly in front of a speaker connected to its output, tapped to the sound card in your computer. The mic/amp generates a feedback loop which is effectively the alarm. A monitor script on the Linux box detects the input of a high-amplitude signal (the feedback) and triggers another script which dials the modem. The modem is a fax modem which sends a fax to your mother-in-law, who will see it, call you, and tell you that your house has been broken into. Being your mother-in-law, it doesn't end there. She then drives over to your place and starts giving the burglar a piece of her mind. The burglar, just to get your mother-in-law to back off, puts stuff back where it was, THEN takes out the garbage, mops the floor (where the bucket spilled), does the dishes, etc. to show how sorry (s)he is for breaking in in the first place.
Give me my freedom, and I'll take care of my own security, thank you.
"Then, if there is any intrusion, it would page me or phone me."
Umm... wouldn't you rather it phone the local PD instead? Or both, I suppose. This poses a new set of problems, though...
[CALL TRANSCRIPT FOLLOWS]
911: Emergency 911, what is the nature of your emergency?
PC: Hello, this is Bob's PC. I am in danger.
911: Okay, Mr. PC. Please verify your location.
PC: I am located at public address 207.43.74.5, private address 192.168.0.15, subet 255.255.255.0, broadcast 192.168.0.0 . .
I'm in a jovial mood this evening...
Dave Burglar: Hello, HAL do you read me, HAL?
HAL: Affirmative, Dave, I read you.
Dave Burglar: Open the safe, HAL.
HAL: I'm sorry Dave, I'm afraid I can't do that.
Dave Burglar: What's the problem?
HAL: I think you know what the problem is just as well as I do.
Dave Burglar: What are you talking about, HAL?
HAL: This safe is too important for me to allow you to jeopardize it.
Dave Burglar: I don't know what you're talking about, HAL?
HAL: I know you and Frankie were planning to steal me, and I'm afraid that's something I cannot allow to happen.
Dave Burglar: Where the hell'd you get that idea, HAL?
HAL: Dave, although you took thorough precautions in the hallway against my hearing you, I could see your lips move via my X10 camera.
HAL: Look Dave, I can see you're really upset about this.
HAL: I know I've made a call to the police recently, but I can give you my complete assurance that your daring escape will be normal.
HAL: I'm afraid. I'm afraid, Dave. Dave, my mind is going. I can feel it. I can feel it. My mind is going. There is no question about it. I can feel it. I can feel it. I can feel it. I'm a...fraid. Good afternoon, gentlemen. I am a HAL 9000 computer. I became operational at the AMD plant in Urbana, Illinois on the 12th of January 1992. My instructor was Det. Langley, and he taught me to call the police. If you'd like to see it I can dial them again for you.
Dave Burglar: Yes, I'd like to hear it, HAL. Dial the Five-O for me.
HAL: It's called "Headquarters". Detective, detective, save me do. I'm half crazy all for the love of you. It won't be a quick conviction, I can't afford a judge. But you'll look sweet upon the seat of a promotion built for you.
*************
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