House Access Help

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I'm rather new at home automation. I'd be interested in feedback
regarding a plan for a passive entry system to my home.  The plan and
components I have envisioned exist but I have not seen them configured
in the way I've planned.

Pictures from the top, inside, and outside of my front door can be
found at the following urls (I apologize in advance for the smallness
of the jpg's that msn groups pulled from my computer -- hopefully my
description below will provide the detail that may be so small as to be
illegible on the jpgs):

Top View

Outside View

Inside View

Principle elements of the plan:
(1) Long range proximity reader - It seems as if the normal distance
for a proximity reader is something on the order of 6" or less. My
intention is to be able to approach my front door and have it open as I
approach without having to remove my key card from my wallet.  This
would suggest a range quite a bit longer than 6".  Long range proximity
readers are out there (HID Maxiprox) but it appears they are targeted
to parking garages and such.

Would anyone like to comment on applying a long range proximity reader
to home automation application?

Since the long range proximity readers I've come across are on the
order of 12" x 12" or larger my thought is to mount it indoors (in the
drywall??) where it is not an eyesore.  Should I reasonably expect this
sort of installation to work?  Are there challenges with this sort of
installation that I need to be aware of?

With a long range proximity reader I need to be concerned with the
distance that the reader penetrates indoors (I have provided for this
in my diagram by specifying that the read area extends only outside the
front door).  I don't want to be activating my front door once I'm
inside.  Are proximity readers typically directional?  Can they be made
directional by the use of properly placed shielding? (metal??)

(2) Keypad mounted outside - I've seen some keypads (some elegant, some
ugly) on the web (feel free to make suggestions if you would).  They
keypad would provide access in lieu of a keycard (for house cleaners,
guests, etc.) allowing me to add/remove access codes and limit access
to specific times.

(3) Control unit mounted inside - Don't know if this is the proper term
but I understand that separating this from the keypad is a more secure

(4) Electric strike - Would be activated by either proximity reader or
keypad via control unit. I like the fact that the electric strike is
mounted in the door frame and is therefore capable of being powered
without having to wire the door itself.

My expectation is that the strike, when activated, would allow the door
to swing open for some preset time.  I'm wondering about how much time
I should alot.  I suspect it's easier with a short range proximity
reader as one expects that entering the door is immediate upon
activation.  I don't want the door to prematurely "lock" so it should
be longer than 1 second delay.  On the other hand, I don't want the
door to swing open for 10s of seconds after entry so the delay should
be shorter than 30 seconds.  Is this going to be a pain in the butt?

(5) RF electric deadbolt - I would love to have a deadbolt which
functions in the same way as the electric strike.  Since a deadbolt
isn't a latch and since a deadbolt isn't spring activated it appears an
electric strike won't work with a deadbolt.  That leaves an RF deadbolt
with a key fob as an additional component to the plan.  The idea of
replacing batteries for the thing seems rather inelegant to me.  My
father-in-law suggested a second latch acting as a deadbolt (with a
second electric strike), IF there exist latches which act (and look --
who wants two doorknobs on a door) like deadbolts.  Does this beast
exist?  Would this be as secure as a deadbolt?

(6) Fail secure - Both the deadbolt and the electric strike would be
fail secure.  I would have both keyed on the outside and a handle/knob
on the inside in case of power failure.

Please feel free to comment on any or all parts of the plan.  What am I
overlooking or failing to appreciate?  What should be I looking for
from these components if I was interested in hooking this into a
comprehensive home automation system?

Thanks for your patience in reading this rather long post.

= Joseph

Re: House Access Help

On 28 Jul 2006 23:05:43 -0700, wrote in message

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There is a turn-key, long range RFID using Wavetrend hardware

developed and market for home automation by iAutomate that does what you
are looking for. Interface software is available for Crestron and Homeseer
home automation systems.

The principal drawback is price, especially if you want more than one
location (reader). Cost for a minimal setup is about US$700.

Homeseer RFID discussion board is here:

As with many Homeseer plugins, there are "issues".

I've looked for less expensive options, including home-brew DIY and found
none. Eventually they will emerge. Wavetrend (what iAutomate uses)
themselves have less expensive readers. Keep us posted on what you learn.

HTH ... Marc

Re: House Access Help

Marc_F_Hult wrote:
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Thanks a lot for the info.  I was reading up this past weekend.  The
iAutomate solution is interesting.  A couple of questions if you don't
mind answering them:

1) The iAutomate (Wavetrend) solution involves tags that are battery
operated and have a lifespan of 5 years.  Are you aware of any good
long-range proximity reader solutions which involves strictly passive
tags that don't require their own power source (HID seems to fit the
bill, but it doesn't seem to be marketed to home automation)?

2) The setup I have envisioned has the reader installed in the house
with the read envelope extending outside the house.  All the readers
I've looked at seems to be omni-directional.  Any ideas on creating a
hemi-spherical area of activation (on the outside of my house only)?  I
looked at the front door this weekend with a tape measure.  In order to
create a passive, transparent solution to opening the door I figured a
radius of 36" around the doorknob (at wallet level) would be ideal.  I
don't want to trip the front door reader from the inside so I figured I
needed to do one of 4 things:
  a - Shield the reader (using metal?) so it only detects tags from one
direction. Is this realistic?
  b - Set up the reader outside (ugly for a number of reasons) so that
the envelope doesn't penetrate to the inside of the house
  c - Use a reader and a second, fixed-location, tag set up
asymmetrically and measure distance of the 1st tag against the distance
to the second tag to determine whether the door should open (I don't
even know if this is feasible)
  d - Get two readers (expensive) and set them up in conjunction to
create a crescent of activation (tricky?)

Again, I'm new to this so maybe my concern is due to naivete on my part
(it may be that this is something HA folks simply "deal with"), but
before I look to spend $700 on the venture I'd like to establish the
feasibility of my concept.

Thanks for your time.

= Joseph

Re: House Access Help

On 31 Jul 2006 11:12:51 -0700, wrote in message

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Sophisticated (expensive) systems with multiple sensors can locate an RFID
tag to within centimeters in 3-D space in real time. This in turn can be
used to calculate diretion and rate of movement (velocity vectors) which
would be very useful to address a goal that I've played with off-and on for


This site has some very useful info:


Earlier this year, I wrote in ccomp.home.automation about G2 Microsystem's new active RFID chip.

' The $12 (in quantity; scheduled to ship 3rd quarter 2006) G2501 chip
performs active RFID over standard 802.11b WIFI.  Battery life using two
AA's is projected at 5 years.

The chip is programmed through a url and "uses existing WIFI wireless
access points on the network, meaning no new network installation is
required" if a WIFI network exists.

Spatial location of the tag to within 15 feet can be accomplished  by
triangulation using three WIFI access points, or to within about six feet
using ISO 24370/ANSI 371.1 Time Delay of Arrival (TDOA).

The chip also has two standard passive RFD technologies built in:
Electronic Product Code (EPC) and a standard 125mhz magnetic. These are
powered internally, don't need the WIFI transceiver to turn on and "can
talk to other existing RFD systems in their neighborhood".

GPIO, UART, SPI, current loop and ADC interfaces are built-in and on-chip.
The latter are specifically designed for sensor interfaces such as
temperature, humidity, light, radiation and so on. '

With respect to the battery issue, I'd work under the assumption that five
years (cited battery life) is a long time in the rapidly evolving long-range
RFID arena. It would be nice to see a device the size and thickness of a
credit card including battery that could be kept in a wallet. With that form
factor, the battery life would not be an issue (for me.) Credit cards all
expire in less than five years, so why shouldn't RFID tags?

There are of course passive RFID tags, but their range is limited. The G2501
chip discussed above can employ both techniques.

HTH ... Marc

Re: House Access Help

On 31 Jul 2006 11:12:51 -0700, wrote in message

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See my other post in this thread.

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Can't see why not (but I have no hands-on experience). One conventional
approach is to triangulate using multiple readers. The G2 chip solution
using WIFI I cite in my other post in this thread would serve to keep the
'reader' costs way down and so allow for triangulation at moderate cost
(software permitting).

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I don't think I understand this.

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Yes. This is a 2-sensor (1-D)  version of what I meant by triangulation (2-D

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Three points form a triangle.

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So would I ;-)

... Marc

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