The Survival Podcast Forum

Survivalism & Self Sufficiency Topics => Homesteading and Self Reliant Living => Home And Business Security => Topic started by: ag2 on March 06, 2011, 10:30:00 PM

Title: What sets off this wireless driveway alert sensor?
Post by: ag2 on March 06, 2011, 10:30:00 PM
http://www.harborfreight.com/wireless-driveway-alert-system-93068.html (http://www.harborfreight.com/wireless-driveway-alert-system-93068.html)

I purchased this wireless sensor primarily to let us know the milk man has delivered milk.  I put the sensor in the box so that it doesn't beep for every vehicle that drives past.  The problem is, I can get two or three false alarms in a day.  Then I can go a few days without a beep, then two or three in a 15 minute period.  Does this operate in a frequency in which it can pick up other transmissions in the same frequency?  I puchased a second unit thinking I had a failing unit.  Same results...false alarms.

Again, the sensor is in the milk box.  No wind.  Lid is closed.  Nobody is near the box.  No electrical motors, phones or microwaves on (or even near) during false alarms.

Perhaps I should avoid harbor freight and purchase higher quality?  I would appreciate recommendations.
Title: Re: What sets off this wireless driveway alert sensor?
Post by: mike77 on March 06, 2011, 11:07:33 PM
It says that it is infrared. With a quality infrared sensor, it probably wouldn't trigger without motion while in a box. That being said, Harbor Freight isn't exactly high quality. It could be that the sensor is false alerting at times and not alerting correctly at others. Or it could be that the receiver isn't picking up the sensor at all and is only getting other transmissions as you said. What is the distance between the sensor and receiver? What kind of walls are in between the two? The description says 200' range, but I would only expect that if they are in direct line of sight with no obstructions. I would say that this might be a place to try other than Harbor Freight. The best solution though would be a wired setup if you can find or make one.
Title: Re: What sets off this wireless driveway alert sensor?
Post by: mxitman on March 13, 2011, 06:10:31 PM
I have one of these and it can be activated by any critter large or small. Ours gets tripped by cats, raccoons, dogs, crows and other large birds, etc... I moved it from the driveway to the basement as an early warning system if someone breaks in. I looked into it and if you want a good alert system then get one that uses a beam and has a back reflector as in the convenience stores...
Title: Re: What sets off this wireless driveway alert sensor?
Post by: mvrck on March 13, 2011, 09:29:25 PM
For the price, they are likely using 900MHz or maybe 2.4GHz, both public frequencies. Not likely using any encoding and so some telephone or other wireless device is making the proper sequence to trigger the receiver.

Is it possible to home brew an external directional antennae? Or make it direct wired?

Good luck!
Title: Re: What sets off this wireless driveway alert sensor?
Post by: KSDeputy on October 03, 2011, 04:16:29 PM
We have an all underground system that is activated by the metal of a vehicle when it pulls up to our gate. It is expensive, but no false alarms. It is made by Cartell. If you are cutting a trench for a phone line, or other use, you just put the wire and sensor in it. The sensor has to be positioned as the directions say.  Our distance from the house to the gate is about 250'. We put the phone lines, and cartell in the same ditch when the house was built 25 years ago, still works fine.
Title: Re: What sets off this wireless driveway alert sensor?
Post by: JerseyVince on October 03, 2011, 05:12:42 PM
Is the Milkbox in the sun? Those sensors pick up temp diferences after they settle to ambient temp. possible they're picking up the  temp difference as the box warms up in the sun
Title: Re: What sets off this wireless driveway alert sensor?
Post by: scott on October 03, 2011, 05:32:19 PM
I got this same thing after our garage got broken into and a bunch of stuff stolen.  It has sent me charging out of the apartment a couple times pistol at the ready in the night but overall been reliable.  It also sets off the chime when the 9v in the sensor dies (which is too frequent for my taste).  I've gotten to not freaking out if it signals but i'll always check when it does.
Our unit is only about 30 feet away through a wall.
For being next to free it's an acceptable warning at least for our purposes.
Title: Re: What sets off this wireless driveway alert sensor?
Post by: ag2 on October 05, 2011, 09:52:33 AM
Is the Milkbox in the sun? Those sensors pick up temp diferences after they settle to ambient temp. possible they're picking up the  temp difference as the box warms up in the sun

The milk box is on the covered porch facing north.  No, it is never in direct sunlight.  I'm going to replace the unit and mount it to the ceiling of the porch facing the front door.  This way it will chime whenever anyone walks up to the door.
Title: Re: What sets off this wireless driveway alert sensor?
Post by: endurance on October 05, 2011, 10:15:36 AM
This (http://www.gadgetshack.com/reporter.html) is the one I have and I've had it since about this time last year with the same set of batteries.  So far, one false alarm and several incidents where it didn't go off when it should have (it's a fairly narrow beam, so I'm thinking about installing another sensor or two so I get overlap).  They have several other options on the website and they're reasonably priced.

I do have a 2.4ghz phone and there doesn't seem to be any interference between the two.  The one false alarm could have easily been wildlife, however, the motion detector light never went off in the same area (still could have been a small critter in one beam path but not the other).