How to build a wireless security system i.e. parts

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noriko
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How to build a wireless security system i.e. parts

Post by noriko » Mon Jul 13, 2009 11:12 am

I would like to install a security system. My driveway is 1000 from the house and I would like some sort of detector when a vehicle passes down my driveway. Does anyone know where to find a good selection of components such as wireless motion detectors and perimeter detectors. I thought a lazar or light beam might be good but have not seen any yet.

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sofaspud
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Re: How to build a wireless security system i.e. parts

Post by sofaspud » Mon Jul 13, 2009 5:14 pm

I suggest putting those terms through Google.

Is that 1000 FEET from the house?
Must be hell on grocery shopping day.

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haklesup
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Re: How to build a wireless security system i.e. parts

Post by haklesup » Mon Jul 13, 2009 5:57 pm

There is really 2 parts to this question. How to sense a vehicle and how to get that signal to go 1000 feet (~0.2 miles). Do you have AC power at the end of your driveway? Does this AC get fed from a circuit originating at the house? Dest this have to run from battery?

As to the sensor, how reliable do you want it to be vs how much do you want to spend. A PIR is very inexpensive and you can get wireless ones at say X-10 but they will also trigger on animals, moving trees etc so you can get lots of false alarms. A light or laser beamneeds a transmitter and reciever and can fail in rain or snow and can become misaligned. A magnetic loop sensor is reliable under various enviornmental conditions and selective to vehcles but can be more expensive and difficult to install. A video camera with motion detection capability (usually through software) is another alternative with similar downfalls to a PIR and higher price but with the benefit of getting a picture at the same time.

Getting the signal back to the house you have some options. A webcam with built in wifi probably won't reach that far but if you can put in a long range hub to boost the signal that might work.. There are probably some dedicated RF baased systems as well but I don't have that knowledge myself.

As for searching, start off with X10, they have been doing outdoor survalance and video via AC power lines and RF for years. Also scan some security websites and of course search the term "driveway sensor"

noriko
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Re: How to build a wireless security system i.e. parts

Post by noriko » Tue Jul 14, 2009 5:45 am

Thank you both for your help. My distance is 1000 feet from the front gate to the house so I am first trying to understand what devices will do the job best or at all. Since I want to detect an entry at the gate I am not sure if a camera will signal to me when a vehicle enters without me seeing it on the camera so an audio signal may be only way to detect intruders.

There is no power at all at the gate. I want to install an automatic locking and opening gate and it will operate from solar and battery power.

I am finding it hard to find a website that lists all devices or perhaps I have seen it all with only motion sensors. I did go to 10x.com and they have lots of good stuff there but I haven't yet found what I need.

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MrAl
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Re: How to build a wireless security system i.e. p

Post by MrAl » Tue Jul 14, 2009 6:16 am

Hi,


The cheapest way is to use a web cam, with motion detect software. The software will
signal you when something moves in the field of the camera.

The only drawback though is that you need a pc computer running 24/7 if you need
security all day and night too.
The nice thing is that you can set the detect level so it doesnt trip on dogs and cats.

Maybe a camera with a telephoto so you dont have to run wires or power. Just an idea.
LEDs vs Bulbs, LEDs are winning.

noriko
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Re: How to build a wireless security system i.e. parts

Post by noriko » Tue Jul 14, 2009 6:53 am

Hello MrAl,

Thanks for your help. My long range goal is to have a system like you describe but I am not sure I am comfortable with the system going down if the power goes out and then I don't think the computer can restart on its own.

I am wondering how much trouble it will be to run a power line out to the gate. Since this is located on a farm I need to bury a power line deeper than farm equipment will rip it up which could be 2.5 feet

I still like the idea of a simple detector either motion or lazar to trigger a buzzer type alarm to let me know when someone enters.

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sofaspud
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Re: How to build a wireless security system i.e. parts

Post by sofaspud » Tue Jul 14, 2009 7:03 am

The description sounds as much annunciator as security. With that in mind, a cable-style detector like those
used by the highway department would be easy and reliable. Is your fencing at all metallic? It might be used
as the transmission line to get at least closer to the house, which should make selecting from options easier.

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MrAl
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Re: How to build a wireless security system i.e. p

Post by MrAl » Tue Jul 14, 2009 7:05 am

Hi again,


I once ran a line about 25 feet long and about 12 inches underground, and another line
about 100 feet and same about 12 inches underground. Using the right cable
(made for underground) it lasts for years and years (over 25 years at last count).
They were both 120vac 60Hz power lines.

I guess 1000 feet is much longer than that so you need to carefully consider voltage
drops. Also, digging 2.5 feet underground is no easy task so you'll need a machine.
You might also consider overhead lines if you dont mind the poles getting in the
way a little. I had used an overhead line though in the past (the 25 feet run mentioned
above) and after the last storm took it out we went with underground cable instead.

You might also consider some battery back up system with a UPS system that would
help keep the system online even when power goes out.
LEDs vs Bulbs, LEDs are winning.

jimmy101
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Re: How to build a wireless security system i.e. p

Post by jimmy101 » Tue Jul 14, 2009 9:53 am

You might consider burying 6 conductor phone line instead of a 120VAC cable. A 1000 foot run for 120VAC, even for circuit of only a couple amps, is going to take a fairly hefty cable rated for burial. Big cost to bury to 2.5', and if it ever gets ripped up, big cost to repair.

Phone cable can be run that far and since it is so cheap to install if it ever gets ripped up it's easy and cheap to repair. The phone company (and hopefully other contractors) use a cable drawing machine that'll lay hundreds of feet of wire in an hour or so. The cable is only down a couple inches but if it is run right next to the driveway it should be safe from farm equipment. (My burried phone line is about 600 feet long. I've cut it a couple times when tilling, digging holes etc. The phone company comes out and replaces the entire run for free, so it must be a pretty cheap process.)

Use a couple conductors for power and a couple for signal from whatever detector you choose.

A 120VAC circuit would have several advantages; the ability to use X10, power at the end of the drive to run an automatic gate and/or lights ...

noriko
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Re: How to build a wireless security system i.e. parts

Post by noriko » Tue Jul 14, 2009 10:57 am

Hello jimmy101,

You bring up a couple very important points I am working around. It has been a while but I think if you want to power a light bulb a thousand feet away the size of the wire used in an AC application must be much larger and much more expensive. (I realize this was brought up already)... AND also the point that DC current can survive a very long run without needing larger wire.

At a later date I planned to install an automatic gate with remote or keypad access. Just maybe it will accomplish the same task and be more secure although out in the country if you put up a gate the locals will start to feel like you are angry with them for some reason...

thanks,

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Lenp
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Re: How to build a wireless security system i.e. parts

Post by Lenp » Tue Jul 14, 2009 12:55 pm

noriko

Whatever you do, I suggest that you install conduit! Two runs of 3/4" PVC will give you all the options and protection you could want for whatever system you my ultimately install. Use one run for the line voltage, the other for the low voltage controls/intercom/camera. You may be able to get a 240 volt gate operator and then set a 240/120 transformer at the gate if you need 120 for other systems. Using 240 volts up to the gate will require more reasonable wire sizes and less voltage drop. The two conduit system will likely meet any local codes that will apply, while mixing line and low voltage in a single conduit probably will not. Additionally, replacing or adding wire is easy.

1000' feet may seem to be a long run to fish through conduit but the trick is to set some 'pull' or junction boxes along the way. Use a shop vac on one end of the conduit and a small plastic bag tied to a long nylon string on the other. The vac will suck the bag and cord right through the conduit! Do use wire lube when pulling the wire. A 1000 feet could be a lot of drag depending on what's being pulled and the bends required. Wire lube makes the pull easier, and reduces strain on the wire. Pull in any spare wires you might ever need and leave a nylon line in the conduits, just in case.

Len
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“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)

noriko
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Re: How to build a wireless security system i.e. parts

Post by noriko » Tue Jul 14, 2009 1:59 pm

One thing I don't understand is that there are wirelss controls for remote controlled airplanes and other toys with a range of more than a thousand feet so there should be devices available for this sort of thing.

I have very little desire to trench a thousand feet for this...

Thanks,

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Re: How to build a wireless security system i.e. parts

Post by Dean Huster » Tue Jul 14, 2009 3:19 pm

If someone is worried about the voltage drop on a 1000 foot Romex line at 120v, why suggest a low voltage phone line? It'll be far, far worse!

For remote locations, solar power, battery and a low-voltage DC motor seems to be the way to go, as long as you have long periods of sunlight for charging, especially in the winter. If you have lots of wind, especially in the winter months, you may consider a small wind charger in addition.

Building a pair of little yagi antennas and using the 40MHz band can provide you with some really cheap transceivers via walkie talkies, baby monitors, intercoms, etc. Sure you have to watch what you do on the various bands as far as legality, but who's listening or caring? We're talkin low power here and you won't be bothering anyone.

Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

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haklesup
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Re: How to build a wireless security system i.e. parts

Post by haklesup » Tue Jul 14, 2009 3:25 pm

So did you google "driveway sensor" These are 2 of the top 3 hits and seem to be exactly what you are looking for. This first link has a 2500 foot range. the second one has 3 pages of products. Magnetic probe, PIR and rubber hose seem to be the most common sensors. Most are wireless with long range. all are audio alerting

http://www.drivewayalert.com/driveway-t ... agod1z7rAA

http://www.homesecuritystore.com/c-69-d ... larms.aspx

There were also others

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Re: How to build a wireless security system i.e. p

Post by jimmy101 » Tue Jul 14, 2009 4:55 pm

If someone is worried about the voltage drop on a 1000 foot Romex line at 120v, why suggest a low voltage phone line? It'll be far, far worse!
Because phone cable is dirt cheap and if it is a low amp and low voltage circuit than it can be the generic phone cable gauge (24G?). Really don't care about voltage drop. Put 18V DC into the wire at the house and a 12V regulator out at the end of the cable. Let the cable's voltage drop do something useful. For getting simple signals back to the house voltage drop is really pretty irrelevant. Even a 50% drop in voltage really wouldn't be a big deal and a couple milliamps of current would be more than enough.

Romex, for a 1000 foot run, 10 A, 120V, 60Hz, assuming no more than 2% voltage drop (which I belive is code in most places), calls for single-0 (0G) wire in a three conductor cable. Last time I looked at prices for cable like that, IIRC, it was more than $1 a foot. 4 and 6 condutor phone cable is more like $0.10/foot. So, more than a $1000 in wire plus probably another couple thousand to bury to 2.5 feet, or $50 in wire and have a local contractor pull the cable for a couple hundred bucks.

If you run a 120VAC circuit it must be up to code and probably needs a building permit. If it isn't it'll be a problem if the local inspector every notices it. If you ever want to sell the property there's a very good chance it'll be a problem if it was installed without a permit. Sale of the house might require not only disconnecting the un-permitted cable but also the physical removal of the cable.

Phone cable for low voltage use doesn't require a permit and has, in most places, no restrictions in the building codes. Bury it 2.5 feet deep, drop it in a 4" deep slit, lay in on top the ground ... whatever, it is permitted by code in most places as long as it is a low voltage, current limited (fused) DC circuit.

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