Re: Unusual Challenge

[ABLE1 <somewhere@xxxxxxxxxxx>]

On 10/21/2021 1:43 PM, Bob La Londe wrote:
> On 10/20/2021 5:31 PM, ABLE1 wrote:
>  > Hey Guys,
>  >
>  > Would like some thoughts on the following challenge.
>  >
>  > Customer has a showroom/office in one building and the shop in another
>  > that is 70 feet away.  They wanted to have a way to get notified in the
>  > shop that a potential customer came into the showroom.
>  >
>  > What I installed was a door contact switch on the entry door and wired
>  > a Linear DXT-31 transmitter and a Linear DXT-701 Receiver in the shop.
>  >
>  >Â  From there I used the contacts on the receiver to trigger and Altronix
>  > timer and the contacts there to trigger a horn/buzzer for about 1 sec.
>  > when the door was opened.
>  >
>  > It has worked quite well for some time but, recently I was told that
>  > it did not respond to ALL entering the showroom.
>  >
>  > I was there a couple of weeks ago and it was working but the the CR2032
>  > batteries were about 60% level and I changed to new.  Tested the
>  > batteries were at 100%. OK.
>  >
>  > I was then informed yesterday that it was still missing some entries.
>  >
>  > I stopped in today and first I tested the door 3 times and it did not
>  > work.
>  >
>  > I tested the batteries.  They were at 100%
>  >
>  > I removed the transmitter and went to the shop and it worked 5 times
>  > in a row.  Or let's say 100%  I put the transmitter back in the attic
>  > above the showroom where it was but staff was in a meeting so I could
>  > not test.
>  >
>  > Was told later that they tried it and it did not work a total of 3 times
>  >
>  > Now the receiver has a wire about 7" long as a antenna.  I have
>  > it hanging over the edge of a window so that the walls would not block
>  > the RF signal. The Transmitter is in the attic space on a vertical
>  > 2x4.  The only thing that might block the signal would be the plywood
>  > and asphalt shingles on the roof, 70' of distance, bug screen and glass
>  > window.
>  >
>  > Needless to say this is a intermittent problem that is NOW not working!!
>  >
>  > So, any thoughts on this before I type something that really made a
>  > difference this afternoon.
>  >
>  > Thanks for any thoughts!!
>  >
>  > Les
> I do not recall which linear receivers I used, but on my shop overhead
> doors I used some with the little F connector screw on antenna.  I then
> used a piece of coax to take that antenna outside.  I get 100%
> reliability (as long as the batteries in my remotes are good) and great
> range.  My driveway is over 100 yards long to the front of the shop, and
> with fresh batteries I get another 100-150 yards range up the road.
> Maybe a little further if I hold the remote out the window of the truck.
>
> Because I am actively involved in every activation I notice the
> batteries start to go by the range the remote works at.  When the
> batteries are low I have to be on my driveway, and sometimes hold the
> remote button down for an extra half second before the receiver
> recognizes the code.
>
> If you are using a regular unsupervised door transmitter I think it just
> sends the code once and that's it.  If the receiver doesn't recognize
> the code it doesn't activate.  Placing the receiver antenna outside in a
> manner similar to what I did may help. Another option might be to setup
> some redundancy.  Set up contacts on the door with bias so that it
> activates the transmitter both when the door opens and when the door
> closes.  It may result in an annoying double notification buzz, and
> battery life will likely be halved.  It might however be more reliable
> for the intended purpose.
>
> Still staying with your current application I suggest one day when you
> take a break for lunch you park across the street and watch the door
> while you mac out.  Maybe a couple different days if you are in the
> area.  You may notice if the door doesn't always close properly or if
> its held partly open when the wind blows from a particular direction.
> Something as simple as repositioning the magnet so its just barely
> within its clear change at maximum closing travel of the door and swings
> through its full clear range before going into its triggered state.  If
> a simple answer like a Z-bracket or spacers won't work you can also
> consider moving the magnet and contact closer to the midpoint of the
> door.  This has the same affect of allowing the door to open slightly
> before triggering which can help overcome door conditions that may not
> allow the circuit to reset otherwise.
>
> Of course the door contact, transmitter, or receiver could also be
> faulty.  Any lighting storms around the time the contact started acting
> up?  We are all familiar with contacts being welded shut, but sometimes
> they break free and act unreliably.
>
> If triggering is an unresolvable issue with a door contact then photo
> beams and IR curtains generally trigger more reliably than a door that
> is standing open, but they have other issues.  The door could block the
> beam.  The sun shining in a glass door or window can affect them.
> Children running around like maniacs can cause runaway activations.
> Mylar ballons tied to a fan can drive you crazy.
>
> Getting further out there.  I once used a basic photo beam door chime
> outdoors for a vehicle drive thru.  The customer thought it was great,
> and it prevented me from having to cut the asphalt to put in a loop.  In
> order to reduce false activations and low sensitivity I made a deep
> steel hood out of steel tube and put it inside of it.  Something like
> that might also work in a regular personnel door setting.  Most business
> doors swing both ways or open out (per code) except possible at WalMart
> where they lock customer area doors while customers are in the store in
> the evenings.
>
> Good luck.  I hope my rambling gave you something useful.
>


Thanks Bob!!  That was some very good ramblings.  :-)

I will hold the secret resolve until Jim and Rocky have a chance
to respond.

Les