Metal (vehicle) detector

Yup! lots of digital trail cameras around now. Poke around at Cabela's website for some examples.

It you happen to have an older digital camera collecting dust that still works, take a look at this sites stuff:

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Complete packages and do-it yourself stuff. No experience with them, just found the site a while back and thought they had some interesting items for sale.

Reply to
Leon Fisk
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If you don't insist on pumping video through it, get a direct wired modem pair, and you can handle things with two of the four pair in the CAT-5 cable. That will be sufficient for up to 9600 baud.

Check out eBay auctions #120352254632 & #400006493229

The search string was:

"short haul" modem

Two of those will give you up to 4000 feet according to the description. Remember that you'll need to bid on and win two of them. They are buy-it-nows, so you have a good chance. It needs 9V to power it, so you can run each end with the supplied power connectors, as long as you have power to the computer at the far end too. Otherwise, you could ship a somewhat higher voltage over the spare pairs in the CAT-5 cable, and add a capacitor and a regulator chip at the far end to pull what is left down to 9V.

But the first thing is to make sure that both ends will send and receive serial data through the RS-232 port to carry your information.

O.K. There are also these: #140234358346

Cheaper, but there is only one auction, and you need two.

Good luck, DoN.

Reply to
DoN. Nichols

As Bill Gates has discovered, each goose craps ~4# a day of fertilizer....

Reply to
David Lesher

I read the website of the inductive sensor manufacturer. The sensor is a big coil of wire driving a couple of hundred feet of wire (twisted pair?).

If you use coax (like RG58), you should be able to put the sensor at one end and the control box at the other end of a 700-foot coax, with no power source or other complications at the detector end. The frequencies to be handled are very low, so loss in the coax is very low.

Next more complex is a one-FET amp at the sensor, powered by phantom power over the coax. I have driven audio signals over 1000 feet of RG59 by this method.

Joe Gwinn

Reply to
Joseph Gwinn

is slightly

all the bad stock photos on this site is amusing

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It's probably been 10 years since I saw an arcnet card, and that was at the junk shop.

Reply to
Cydrome Leader

Just checked coax prices. The RG59U in my surveillance system was only 5 cents a foot. Mine is in 75 foot lengths with f type (TV) connecters. couplers are cheap, and easily waterproofed. I changed the extreme ends to BNC. Ordinary speaker wire is fine for the 12V supply, and works over long runs of wire.

Steve R.

Reply to
Steve R.

Can I run multiple cameras thru one RG59U coax 700' long? I can live with slower refresh rates, 1/4 sec would be plenty fast.

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/

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Reply to
nick hull

On Sat, 20 Dec 2008 08:18:14 -0600, the infamous nick hull scrawled the following:

Sure. Just put 120v power and the video controller in a climate-controlled house at the far end and switch it to a single coax feed to your house.

Hmm, there -may- be battery-powered remote switches available, or you could design your own with RC hardware and DPDT switches.

Another alternative is to use wireless video cams, such as X-10 and other mfgrs put out.

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Search eBay for "wireless video systems" and find a 4-cam set with 2 pan and tilts for $259. (only 100' range, though)

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for 1k'-1/4/7/12 mile range is considerably more expensive.

-- It is pretty hard to tell what does bring happiness; poverty and wealth have both failed. -- Kin Hubbard

Reply to
Larry Jaques

What you need is a tall pole next to your entry gate. Go down to the local medical supply house and get a realistic looking plastic skull. Place it atop the pole. Hand a 'No Trespassing' sign beneath it.

Most people will get the hint.

Reply to
Paul Hovnanian P.E.

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"They couldn't hit an elephant at this dist..." Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of Spotsylvania

Reply to
Gunner Asch

On Sun, 21 Dec 2008 03:00:31 -0800, the infamous Gunner Asch scrawled the following:

The 3rd time I tried this link this morning, I waited for about 5 minutes and it never did fully load.

Here's a cartoon I'm sur you'll love:

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for today, Sunday, 12/21/08

P.S: Happy Solstice / Joyous Saturnalia to all today!

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Reply to
Larry Jaques

Print some of these up and put em along the fence line

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Dig a few small craters and put some clothing bits in and around them, inside the fence.

Or some of these....

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Gunner

"They couldn't hit an elephant at this dist..." Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of Spotsylvania

Reply to
Gunner Asch

You will need a separate cable for each cam.

Steve R.

Reply to
Steve R.

Or a remote controlled video switcher.

Reply to
Michael A. Terrell

I don't know how good a TV picture will emerge from 700 feet of RG58. Actually, video links are usually 75 ohms (not 50 ohms), so make that RG59 (not RG58).

I've seen writeups on the CCTV systems of casinos, and they now use fiber everywhere. So, one could run a copper power cable and a fiber signal cable together.

Joe Gwinn

Reply to
Joseph Gwinn

It will still be worthless. You want RG-6 or larger, or modulate the video and send it as RF. The baseband signal will lose most of the higher frequencies (lose resolution) at that distance. Look at the data on the cable you are looking at and see how steep the rolloff is from DC to 5 MHz.

Reply to
Michael A. Terrell

I picked up a GE GE5806DWM "Driveway Monitor Alert Unit" at Lowe's several years ago. It appears to be a fluxgate magnetometer.

The sensor is about 2x3x6" and eats a pair of "C" cells every month. I set a 4' piece of 4" plastic DWV pipe with about 12" buried; the exposed part was painted with plastic furniture paint. The top cap was left loose so I can change batteries. Sensor has a detection range of about 30'. The thing runs on 433.92MHz. The receiver only "beeps", no contacts for external alarms; also alerts on low transmitter battery. My receiver is in the den and the sensor is mounted about 300' up the driveway with a clear line of sight. I didn't try it at longer range as the upper end of the driveway is shared with a neighbor. If you put an external yaggi antenna on an appropriate pole on the receiver end you could probably make the 700'.

The box worked without a single false alarm for a couple of years, but for the last two or three years I have gotten multiple false alarms when strong weather fronts come through. A friend of mine about 20 miles away also has one of the things and the couple of times I have asked him he has also had false alarms about the same time. Guess there are some earth field glitches associated with strong weather fronts. Also had a couple of false alarms during thunderstorms. I have considered adding a second unit with some processing to ignore simultaneous alarms.

Looks like this is the current incarnation: href="

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"A high antenna at the house should be able to stretch the range. Powering the transmitter from the AC line should not be a major problem, just add a REALLY GOOD surge supressor to the power line as

700' of (I presume) buried power cable is really good at picking up lightning strikes.

As to perimeter sensing, anything optical has to be able to handle flapping brush, geese, swans, rain, fog, and bambi 8o) So far it looks like sticking to vehicles and the inside of structures.

Reply to
kabowers

I need one of those - was thinking of optical. Mag is better. Since we have hogs, and other vermin like deer that walk the driveways.

Remember lightening is a high current that discharges into the ground. Magnetic and electromagnetic flux is generated and it far exceeds that of a power line.

I'd rather have a random false once in a while than no notice at all.

Mart> >

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"> A high antenna at the house should be able to stretch the range.

Reply to
Martin H. Eastburn

My thought was to mount the second sensor about 100' up/down the road from the first so a vehicle would only trigger one at a time. Of course I wouldn't get an alarm if a column of tanks came after me 8o) Another option would be to put the second sensor just past the break in the circle drive so I could determine if they were heading for the front door or the shop/back door.

As to thunderstorms, the falses are rare. OTOH weather fronts can generate falses every few seconds for >15 min. I don't know how long they last because that's when I unplug the receiver.

Reply to
kabowers

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