I am looking for a sensor to give me some warning when someone comes down my driveway. The driveway is 1200' long, esentially straight; clear line of sight. I would like to place the sensor 300 to 9oo feet up the drive. Cutting up the driveway to bury a coil is not an option. I'm looking to keep under $150 US.
This unit from Catch-a-Call looks interesting. Does anyone know anything about it?
In article , email@example.com (keith bowers) writes: | I am looking for a sensor to give me some warning when someone comes down my | driveway. The driveway is 1200' long, esentially straight; clear line of | sight. I would like to place the sensor 300 to 9oo feet up the drive. | Cutting up the driveway to bury a coil is not an option. I'm looking to | keep under $150 US. | | This unit from Catch-a-Call looks interesting. Does anyone know anything | about it? |
I have a slightly older version (same transmitter; different receiver). It works reasonably well, though it does false a bit. The case isn't really water proof and I had some corrosion problems after a year. The receiver did not allow you to de-register a device (or even to erase all memory) but that may have been fixed in the new version.
Note that there is a similar wireless product that uses a magnetometer instead of a passive IR detector. It did not work well at all for me. Also, 1000 feet is very optimistic for either wireless device...
The hard-wired magnetometers work well even if burried to one side of the driveway, i.e., without cutting. This is especially true when you have a long driveway so you can set the sensitivity high without worrying about passing cars in the street triggering the alert.
I tried several wireless devices and none of them lasted or was all that reliable. Finally settled on Cartell. Hard wired, but can detect from the side of the driveway just fine. I got it at Worthington.
So much for that one. I've had to replace too many coroded sensors the last few years to buy anymore leakers. If it's going to be used outside it doesn't cost much for the manufacturer to conformal coat the PCBs. Exxon did it from the start of their electronic gas pump interfaces thirty-odd years ago. The stuff lasted forever in horrible conditions.
Very interesting idea, but a bit too much strain in the budget for now (a quick Google didn't find any US distributors; just Banner themselves). The basic principal has all sorts of posibilities. I wonder if the Hitachi compass module that Parallax is selling could be used to do the same thing.
A friend that I subcontract for has used a unit made by Optex with good results. He gets them at the local Locksmith supply house. When I Googled for them I came up with this:
the Long Range System also looks interesting, uses vhf frequencies in the
151-154MHz range with 2 watts of power. Should be good for at least a mile or better depending on terrain/obstructions. The WMA-3000 also looks good for longer range.
Have never dealt with this vendor and have no hands on with any other than the Optex my friend uses.
I know of one that is inserted under the driveway and detects changes in the magnetic field. You dont have to cut up the drive as it can be inserte from the side through an L shapped bit of conduit. Getting the conduit in may mean a little digging on the side of the drive and using some technique for digging the hole under the drive (but this is not new).
Once in it can be removed easily.
I dont remember the brand, but it was for the automation industry (not home automation) and was not very expensive. A google search may reveal something. I need to find the notes I had for it and if I do I will post them here.
Larry, I beg to differ, the frequencies involved are part of a service called Multi Use Radio Service. The FCC took 5 VHF frequencies (some of the 'color dot' frequencies) and turned them into a new CB band for voice and data. 2watt power limit, 60 foot maximum antenna height. No license required.
and here for general rules and regs:
and here for technical requirements:
I discovered this a while back while looking into a new frequency assignment and license for a client (I generally don't do 2 way radio work anymore but the client is a friend, going to do a 4 frequency assignment on UHF, he owns a construction company). Won't meet my friend's needs but useful to many others.
In article , firstname.lastname@example.org (L. M. Rappaport) writes: | On Tue, 4 Oct 2005 22:26:33 -0500, "Todd F" | wrote (with possible editing): | | ...snip | | >the Long Range System also looks interesting, uses vhf frequencies in the | >151-154MHz range with 2 watts of power. Should be good for at least a mile | >or better depending on terrain/obstructions. The WMA-3000 also looks good | >for longer range. | | Todd, anything in this range at this power requires an FCC-issued | commercial license, at least in the United States.
It looks like they are using MURS, a VHF service which allows up to 2 watts and requires no license. You may recall that MURS was supposed to be a CB service that offered some of the technical abilities of ham radio (including in particular data transmission) without the commercial use restrictions and license requirements (but with channelized frequencies). At first it appeared that this would come to pass, and under the initial rules it would have been permissible for an end user to combine an off-the-shelf MURS radio and a TAC for simple data communications.
Unfortunately, certain groups lobbied the FCC to prohibit repeater operation and to make vague restrictions on packet switching. The result appears to be that manufacturers got a new license-free range in which they can build high- power products while end users are pretty much constrained to voice unless they buy such products.
Getting back to the product in question, it wasn't obvious that it provides any kind of signal output other than the voice prompt. That could be a problem.
It has a 12V output trigger for home automation systems. That's better than nothing; many only have a light and chime. But the system supports up to 16 sensors; why can't they just put out the code on four terminals? Is it really that difficult to keep automators in mind?
At least with the four-sensor version of the Cartell system, the sensors are wired in series external to the controller. In other words, the signals are OR'd and so there is no 1-of-16 ("put the code out on four terminals" ) data to report.
If you want multiple, independent sensors, the least expensive route may be the Cartell CP-2 self-contained unit
I also live in the country with a long driveway, and don't like surprises.
I played with the various ones out there, built special antennas, and none were reliable.
Then I discovered:
It works precisely as advertised, zero range problems. Plug and play.
My receiver is mounted on the porch, and the receiver has a N.O. relay which closes on trigger. I run that into an X10 transmit module to inject a signal into the power line, beep the driveway beeper, turn on all floodlights and start the video cameras in a scan sequence.
The only problem I have had is ants getting in and building nests, causing false alarms. I solved this by cutting little pieces of No Pest strips and tucking them around the battery. The electronics part is sealed in silicone. The batt compartment has a door, and room for some slivers of No Pest which I change every time I change the 9V batt, which is about every year and a half.
Tech support is excellent and toll free.
I buy mine from
but you probably can find other sources. Shomer has been the cheapest and good service.
I think this may do your job. I'm running at least a thousand feet, and in playing, the thing will trip the receiver in the barn, meaning I have a significant fade margin.
Regards ... Steve
********************************************************************* Steve Uhrig, SWS Security, Maryland (USA) Mfrs of electronic surveillance equip mailto: email@example.com website
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