The Ultimate Home Alarm System

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The alarm mlist


Random Thoughts

  • bear in mind that security systems could be stolen
  • nice if it works during a power outage, but challenging to design
  • most commercial systems require a POTS and use a lead-acid battery - we can do better

It's really nice to integrate an alarm and physical security, so that you turn off alarms when unlocking, or vice-versa. Anything that works without human intervention is likely more reliable than something which relies on you remembering to do something.

I consider this a "physical IDS".

Also, if you're leaving (locking doors, turning on alarm), perhaps turning off lights makes sense too, to save energy.

Sensor Ideas

Motion Detection


  • PIR doesn't work very well when ambient temperature approaches body temperature - may result in constant false alarms, especially if A/C goes out
  • kind of sucks - just sends boolean yes/no signal
  • depends on fresnel lens and the motion being perpendicular to the detector

Video Motion Detection

  • CCD is better than CMOS for video motion detection, since there's less noise
  • cloudy days can set off motion detectors
  • you might want to mask off parts of image for motion detection
  • motion (detection)


  • zoneminder and a tutorial on using zoneminder for video surveillance

  • motion tracking linux google search

  • analog cameras suck - require digitizer to do anything with them, ties up digitizer!

  • CMOS can suck - may be too noisy to do motion detection - prefer CCD

  • going froma analog to digital (digitizing board) can introduce noise which can mess up motion detection

  • left object detection (used in airports to detect bombs)

  • experience with video drivers in Linux
    • there's v4l2 v4l2, then another interface called uvc
    • i ended up using uvc_streamer
    • and the driver that is "good" is gspca
    • luvcviewer was the program that i ended getting the camera to show up with
  • desirable that they be hidden, or out of easy reach, so people don't break them down as soon as they enter

  • would be nice to be able to reposition them occasionally for surprise effect

  • in low light conditions, black and white is better than color - some high-end cameras can switch automatically

  • the IR cameras use IR LED illuminators, and cheap ones have very short range - and no color at night of course

  • video is high bandwidth, bear that in mind when processing/recording

  • you will want timecodes for evidentiary reasons

  • you might want to design it so that it is only looked at if something bad happens to preserve privacy

  • placement is critical - you want to place them strategically to maximize chance of burglar being seen

  • for hallway cameras, might not need pan/tilt, but for remote investigation, you can zoom in on faces, and possibly avoid a FP and trip to premises

  • TODO: look into Axis cameras

  • insane covert IR illumation

  • Pro LED illuminator array

  • better than IR is to turn on lights after 2 seconds of capture

USB cameras

  • length of USB cables to webcams is limited
  • USB webcams have limited focal depth
  • take off IR filter and you get NIR (but not thermal)
  • not many meant for covert use
  • you can be limited by the number of USB ports, overall USB bandwidth

Polycom Equipment

  • not cheap - $700/unit? - but I already have some
  • pan/tilt/zoom awesomeness
  • 20x optical zoom
  • web-controllable
  • can you imagine a camera following you around?
  • crappy old H.323 video standard, hard to firewall properly


  • Foscam FI18918W camera from Amazon - I highly recommend reading all the reviews so you know what you're getting into
  • very minimal documentation, poor translation
  • requires broadcasting SSID
  • supports 802.11B/G, WPA AES
  • kind of quirky - you'll have to do some research, spend perhaps 6+ hours getting it all to work
  • has video and 2-way audio (so you can chat with the thief?)
  • tends to shock me if I touch the metal antenna mount
  • possible to view and record with vlc
  • firmware may contain spyware (and I really mean "spy") - just a rumor I heard - be careful
  • can be controlled with Android IP Cam Viewer software
  • can be controlled with Foscam Surveillance Pro on iPad, iPhone
  • under $100 - very affordable!


Someone on the net says:

A bit pricey around $1000, the mobotix M24 SEC or M24 SEC-night has a 360 hemisphere below the unit (mounts for outdoor and housing available). 3 Megapixels ie MXGA 2048x1535 max density.

Also can do license plate capture on stationary and slowly moving vehicles with easy - if you bolt down speed bumps and some curbs to channel the vehicles right in view of the camera.

Can be expanded into alarm systems with mobotix moboIO, runs via the web on standard protocols i.e. SMB/NFS, HTTP/HTTPS, can act as as DHCP server, and the cam's motions detectors and logical alerts can combine between 2 or more cams.

Can be wedged into zoneminder for recording or record to NFS or SMB or local USB disk OR thumbdrive or...

Chats to my iphone with extreme ease (I am using it at a client for robbery and shoplifting protection so that I have digitally signed court ready HD images (the cam allows an ssl cert to be installed for signing the MJPEGS making up the video stream. I havent seen ANY other manufacturer at the pricing level do this (not even in more expensive cams).

It also is powered via POE requires neither video balun NOR cabling power supplies etc not does it require an NVR to run, it has both microphone (also alarms on sound threshold if set) and speaker accessible to from SIP and chats to both... ("STOP THIEF")...

Internal embedded OS IS linux (big surprise).


  • noise integrator - to detect prolonged, loud sounds (banging)
  • glass break detection
  • voice detection
  • multiple microphones in place feeding into system
  • limited audio inputs on standard Linux systems, may require audio hardware
  • recording audio may violate local wiretap laws - check with a lawyer
  • wireless audio devices may be illegal as bugs - check with a lawyer
  • line level audio requires digitizing, and multiple ADCs - your computer may be limited in this
  • would be nice to be able to talk with intruders - this is called two-way audio

Wind Sensors


  • Sonmicro makes a microcontroller that can do read/write for RFID for access control - it's quite cheap compared to most RFID hardware

Wireless Sniffing

One possibly novel idea I had was to integrate WiFi and Bluetooth MAC address sniffing into the alarm system. Perhaps this could be extended into phones. One could also use something like karma to create a WAP or Bluetooth station that probes for as much information as possible. This invisible monitoring could also be used to verify the identity of a thief later. Of course one would probably need to monitor generally in order to eliminate nearby residents, though it is likely that thieves visited the place ealier. In fact, that might be useful to correlate with camera systems; they might hide their identity on the theft night but not on the reconnaisance.



Status Indicators

  • visual indicator when monitoring is on (from inside)
  • indicator from outside when alarm is on

Turning On/Off

  • automatic on when I leave (easy to use = more reliable = less forgetting)
    • when I dissociate from WAP
    • by radio of other kind (have screenlock USB dongle that does it, need to reverse-engineer)
    • by a push-button on outside of door
  • automatic off when in range is dangerous (proxy/relay attack)

  • by cell phone (asterisk AGI)

  • over Internet (in case you're at work and forgot to enable)

Local Networking


  • WiFi (DSSS, encrypted)
  • Bluetooth (FH, encrypted)
  • Zigbee/Nordic
  • cheap radio module ($1 ea, lasts for months on one battery)
  • issues: privacy, jamming, battery life
  • easier to install, which may mean it actually gets done - or can get set up faster, to serve until you run wires
  • can run WiFi to controller and another short-range wireless to nodes - one advantage of running your own protocols is that you can design your own FH schema in your own bands
  • can just throw an alarm if it's jammed
  • you can also switch from one low power mode if everything is okay, and then if jamming is detected, you skip into other bands
  • possible to shift frequences with a RF mixer, or change input reference signal


  • multiplexing/polling allows us to have many sensors on few inputs
  • what kind of wiring to use for wired sensors? NC pairs of wires - prevents cutting but not shorting
  • I like phone/ethernet line/connectors, simple, inexpensive, widely available, easy to make
  • can do PoE to a camera; PoE switches are coming down in price, and some PoE "injectors" on Amazon are around $40, 8 port gigabit + POE is around $175
  • many commercial systems require "dry pairs" from local telco to monitoring facility


  • periodic handshake with remote nodes; alarm if handshake fails, for wired and wireless
  • this is called "AA grade line security"
  • consider WiMax network USB dongle (Clear/Clearwire, etc.)
  • some devices (Clear/Clearwire, Verizon, etc.) for backup comms - some can act as modem and WiFi hotspot

Some sysadmins I know use IRC servers to get alerts out, because in an emergency, it tends to route data pretty well - it has evolved while facing numerous DDoS attacks on public servers.

Other Hardware

Intrusion Response

Sonic Response

  • Ultrasound be used as a weapon to encourage intruders to leave. Please make it non-lethal!
  • If you search google for variations "ultrasonic weapon" and "ultrasonic pain" and "ultrasonic generator", you'll find many plans