Perimeter intrusion detection

Discussion in 'General Survival and Preparedness' started by Airtime, Oct 26, 2012.

  1. Airtime

    Airtime Monkey+++

    So, there is the Dakota alert system that employs passive infrared motion sensors or magnetic vehicle sensors that then trigger a verbal message transmission on a MURS radio channel. It is limited to only 4 prerecorded messages and the PIR sensor is good to like 30 feet. If trying to secure a perimeter these can be significant limitations especially if early warning detection well away from the house or retreat is desired. So what other options are members here aware of? Does anyone know of a device that could have a voice message recorded and then could key a radio and play back the recording to the radio's mic input when a signal from a sensor, motion detector, trip wire, photobeam or some other input triggers this device?? This would allow one to connect what ever radio they wanted and configure any message they'd want.

  2. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    First off I would not use MURS Channels, as they are well known, few, and easily scanned, so when triggered you not only alert yourself, you potentially Alert the Intruder that he has triggered your detector. Much better to use one of the SECURE Phones like an i355 connected to your sensor by a modified external Earbud/Mic/Ptt... Non scannable non-DFable and has a range similar to a FRS Radio, plus they are Dirt Cheap, and readily available..... .....
  3. Brokor

    Brokor Live Free or Cry Moderator Site Supporter+++ Founding Member

    chelloveck likes this.
  4. Pax Mentis

    Pax Mentis Philosopher King |RIP 11-4-2017

    Personally, I use mobile sensors transmitting on the canine channel...

    VisuTrac, BTPost and oldawg like this.
  5. oldawg

    oldawg Monkey+++

    And if they don't deazz the ao rapidly the alarm becomes the intruder destruction machine.:)
  6. Airtime

    Airtime Monkey+++

    Some of the other threads such as dealing with the threats presented by the Bubbas down the road and the discussion about the role of dogs when the SHTF in part prompt this inquiry. It is probable that multiple forms of early warning and intruder detection are wise. I have the k9 warning systems but I know from experience they are imperfect. I want to augment them with technology. Yeah maybe EMP might render it useless but there are many more situations when they would not be rendered useless. Plus technology can provide me warning if I have to venture into town assist some nearby family. So the original question remains. What kind of remote sensing besides the Dakota alert or Chamberlain driveway warning systems you others have or know about?? Thanks.

  7. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    You might just consider using some 26 Gauge Wire strung about at the three foot level in a series of loops around your perimeter, And use continuity as a senser. If something breaks the loop, the alarm sounds at the monitor site. Simple and straight forward.
    Brokor likes this.
  8. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

    There are simple sensors made for alerting when a car enters your driveway, it is a radio signal, and pretty cheap, they are made to alert you to guests arriving, but For cars though (or some one with enough metal) I would sink a loop detector at gate access.(or any funnel) even if they dismount and enter on foot, adding coils to a loop detector makes it more sensitive. Works on the same principle as an electro magnet. usually 12vt and low current drain, it could be a stand-alone sentry with a radio transmitter driven by buried battery and recharged by solar panel. These usually trigger motors through relays, but I would think an autodialer could send a text message, or voice message. They are used by telemarketers to call us at dinner time, and they can run through a long list of phone numbers is minutes. Even if the voice message was nothing more than "intruder" then dial the next number.
  9. -06

    -06 Monkey+++

    Monofilment and active or passive alarms work also. Trip flares set off my various means will get lots of attention. The rules of "do not pull on a loose or cut a tight wire" can be bypassed by a continuity alarm. Listening posts/sentries/patrols are always an option if you have the personel.
  10. melbo

    melbo Hunter Gatherer Administrator Founding Member

    I thought MURS was pretty uncommon among the non radio-heads, I can't imagine seeing an intruding thief with a MURS handset but maybe.
    I've installed Dakota systems and one of the nice features is that you can also get handhelds that can communicate with the base.
  11. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

    The question posed was "So what other options are members here aware of? Does anyone know of a device that could have a voice message recorded and then could key a radio and play back the recording to the radio's mic input when a signal from a sensor, motion detector, trip wire, photobeam or some other input triggers this device??" I believe this was to be a quiet alarm without live monitoring. With enough people, you could link arms and sink Kum-Bi-A, and for get about sensors at all. The real question is, how to alert me, with the most lead time, and not them?

  12. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

    Here is another method for your perusal. The now make game cameras with the ability to transmit a picture as it is taken, to your laptop, or even a cell phone as an email. Or there is this system, that allows for live monitoring of game cameras from anywhere in the world. (Moultry Cameras) moultrie5 (1).
  13. Brokor

    Brokor Live Free or Cry Moderator Site Supporter+++ Founding Member

    I don't fully see the reason you would want a voice message alert sent to a radio. Generally, the simplest methods tend to work the best, but if you wanted to make this work, you could set up a small RF transmitter on a switch as a sending/alert unit, attach to a continuity trip wire and sit with a radio on the frequency you wish. When tripped, the RF transmitter could send out a programmed series of clicks or recorded message. The downsides are, power for the units and being tied to the AO to monitor, not to mention setting this all up. You could do some additional electrical work and make it trip by means of a photocell or laser beam. Again, power is a downside. A simple continuity loop is pretty much faultless. I mean, what would be the next step? An implanted chip with the voice of your wife singing to you that an enemy is approaching? An iPhone app with your favorite ringtone and dancing bears on the screen? I just don't see the point, lol.
    Pax Mentis likes this.
  14. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

    Power is always a concern. But loop detectors to pick up large chunks of metal, can be stand alone, and solar charged from a small panel high in a tree, or on top of a roof or wall. they use little power, and report by radio, not wires. Game cameras also can report in real time by cell phone. No wires to fail, short, ground, or be noticed. Game cameras are designed to blend in, and loop detectors can be completely invisible. As for a voice signal....only reason I could see would be lack of confusion.(clear threat)
  15. Airtime

    Airtime Monkey+++

    A few responses to various comments:
    Yes, there is a desire and advantages to be alerted and the intruders not be aware of that detection. It is also very desirable to pick up their presence while they are still a ways off. There are not many in my group of trusted friends and family so we need force multipliers.

    Why would one want a voice message? I could move to a flanking position and hear in my comms messages from sensors as to bubba's position. Would it be perfect? Heck no but the key is to operate without dependance on this kind of intel but to exploit it when the technology does deliver. The Dakota system provides for only 4 sectors and alerts on a MURS radio channel. I'd like a different radio band including potentially the iDen direct talk phones. If an outer early warning perimeter is established I could be looking at that being close to a mile and a half in length. More than just four sectors would be good. I've found some 200 meter range IR photobeam systems that aren't terrible price wise but still rich so I may design my own. I am hoping others have had similar thoughts and I can R&D (rip off and duplicate) their discoveries of existing products that might be of interest.

    Thanks for the game camera links. I need to look into this some more and if there are systems that don't use cell phone infrastructure.

    Several pulsed IR laser diodes for a perimeter photo detection system wouldn't use much juice. A small solar panel would be quite adequate to power the senders and receivers.

    Would this take time and effort to set up? Yep. But my home is also our BOL. I am a belt and suspenders kind of guy and don't want all my warning and detection eggs in one basket. A photobeam/laser that is not visible except to NV gear which most Bubbas don't have could warn me when Bubba is 500 meters or more away. Then PIR and cameras with motion sensing software could provide close perimeter monitoring. Of course the dogs augment all that.

    You know it's one thing to threaten Bubba when he's beating on the door. It is a very different response to plant a nice bright green laser on his chest when he is mustering up the courage to come knocking with his buds when they are still a quarter mile away. And an ever better response to illuminate them up from the front and from behind them at the same time. Early warning is a key to this type of posture to make them want to just stay way far away.

    As always thanks for the thoughts these are helpful. Got some "just thinking" to do.

  16. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    The thing about IR Diodes, is if you pulse them, with a 5% duty Cycle, you save a whole lot of power. Same with Laser Diodes. If your not an Electronic Guru, then you would need someone in you local group to design the receiver to look for a pulse to reset the internal timer. Say 5 missed pulses and it triggers the alarm option.
    Conceivably this, along with CMos logic, one could make a system that would run for months on a 9 Vdc battery.
    The same is also true for a Continuity Wire type system, and if it was linked back to Home Base via Pulsed IR, or Laser Diode, a very stealthy system that uses NO RADIO Telltails.... ....
  17. Airtime

    Airtime Monkey+++

    I'm hoping to find some off-the-shelf solutions. But if I have to design something I was thinking pulsing at less than a 1% duty cycle at maybe a 10 kHz frequency and a unique code pattern. Then each diode transmitter can be uniquely identified at the receivers. Maybe stack say 4-5 diodes inside a "fence post" each spaced 10-12 inches apart and have a similar post with receivers similarly spaced. Locate these several hundred meters apart and spead the beams enough such that each diode transmitter hits all of the photo receivers. This creates a photo electric fence that not only has beams that run top diode to top receiver but also create diagonal sensing lines between the top diode and each of the receivers down the post. Ditto this for all the IR diodes. So we have an invisible fence with horizontal and criss cross detection lines between the two posts. Then with some simple signal processing of sensor signals we can filter out false detections of birds, leaves, etc. I found some products that effectively do this but a several hundred bucks per transmitter and sensor pair is way too rich for a dozen or more systems.

    The idea of using a coded laser to "phone home" is a good idea. Thanks for that. There is quite a plethora of low cost 2.4 gHz network links for wifi etc and coupled with a small patch or yagi directional high gain antenna would likely also be adequate for that phone home link.

    Hmmmmm...... Got me just thinking again. Thanks.

  18. Brokor

    Brokor Live Free or Cry Moderator Site Supporter+++ Founding Member

    Next you will be telling us you are looking for some thermal imaging cameras by Ratheon, vibration sensors and plug-n-play robotic NSA agents of your own.

  19. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

    Naw, just harvest the FLER unit from the first police copter to go down in your area, [shtf]
  20. Airtime

    Airtime Monkey+++

    Very good. Naa.... Already researched the thermal cameras. Can't find one from a Cadallac and not able to pony up the 2500 bucks for the small Pathfind camera from FLIR.

    Now NSA agents.... Hmmmm... any hot ones that can firmly grip a Glock available? Just thinkin (honest dear, I was just thinkin and only looking at the survival monkey website... honestly, I swear!)

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