RE: 1 wire temperature monitoring

["Nigel Giddings" <nigel@xxxxxxxxxxxxxx>]

Kevin,

The important question of parasitic power is covered by the HA7NET, this
is=
from the manual:

Regarding pin 6 (Vdd)...inside the HA7Net are three jumpers located next
to=
the RJ11 jacks. By manipulating these jumpers, pin 6 can be configured for=
any of three states:
=20
*+5 Volt DC power supplied, up to 200mA. This might be useful if you want
t=
o provide external power to sensors such as the DS18x20.
=20
*GND- Pin will be held to the common 1-Wire GND level

*Floating- The pin will be physically disconnected inside the HA7Net. This
=
might be useful if you have other devices on the bus that need to control
t=
his line.

I like the look of OPNODE, any idea of price? I will drop them an e-mail
to=
ask....

Having three legs is handy but they all need to start from the same point
i=
n space. 3xOPNODEs in different locations would be much more flexible
(cost=
may be a factor). I do use xAP with Homeseer but I'm still a bit flaky on =
how some of it works and without a development network all experimentation
=
gets done on the 'production environment' not good for WAF. Maybe a
develop=
ment environment should be on my todo list...

I have subscribed to the OPNODE yahoo group as it looks as if it could
beco=
me very interesting...

Nigel

-----Original Message-----
From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf Of K=
evin Hawkins
Sent: 03 January 2009 18:50
To: ukha_d@xxxxxxx
Subject: Re: [ukha_d] 1 wire temperature monitoring

Hi Nigel,

Interesting - do the three legs support both parasatic and powered /=20
three wire operation ? I had a lot of troubles with parasitic powered=20
devices but when I moved to three wire 'powered' setup all the sensors=20
appear to function fine - around 70 m of cable length (CAT5) and 30=20
sensors - mostly 18B20's. I know from other posts that getting it=20
working reliably is a bit of an art though.

I'm currently using OPNone (link below) which is again Ethernet=20
connected and uses xAP so directly integrates into any xAP aware app=20
including HomeSeer. It has some additional 'smarts' including monitoring=20
sensor values and issuing xAP commands directly to other devices=20
automatically based on logic/threholds and the time. eg it can turn on=20
your boiler if the temp goes below certain levels. It doesn't have the=20
three independent 1-wire legs though and it has around a dozen specific=20
1-wire devices it supports rather than yours which say 'all' - so I=20
think you'll be better with the one you found.

http://www.opnode.org/dokuwiki/doku.php?id=3Dprojects

Kevin

Nigel Giddings wrote:
> Hi,
>
>=20
>
> I have been looking at extending my 1-wire temperature monitoring in
the =
house. 1-wire was never designed for long cable lengths and begins to
suffe=
r reflections if the cables get too long... well I have reached that point.
>
>=20
>
> I want to monitor some of the H/W pipes to things like the showers and
ba=
ths, to trigger towel rail heating and also temperatures on the heat
exchan=
ger to see if it actually exchanges heat as well as a couple more room and
=
equipment rack probes....
>
>=20
>
> However, I have run up against the cable length issue.
>
>=20
>
> What I have found is a Hub that effectively separates three daisy
chains =
of sensors to enable three lengths of cable with sensors.
>
>=20
>
> http://www.homechip.com/catalog/product_info.php?cPath=3D22&products_id=
=3D109
>
>=20
>
> What is also nice about this is that it connects to the PC via
Ethernet s=
o you can remotely position it wherever you have Ethernet connectivity,
eve=
n over the internet....
>
>=20
>
> I intend to use with Homeseer with a plug-in called Ultra1wire to do
all =
the leg work and place the data into virtual devices in Homeseer which can
=
then be used however I want.
>
>=20
>
> http://forums.homeseer.com/forumdisplay.php?f=3D854
($29.95)
>
>=20
>
> They are in stock, spoke with them today, and will probably order 1 on
Mo=
nday (=A399 + VAT + P&P =A37)=20
>
>=20
>
> Just thought I would pass it by the list to see if any other
alternatives=
exist....
>
>=20
>
> Nigel
>
>
>
> [Non-text portions of this message have been removed]
>
>
> ------------------------------------
>
> ********************************************
> Limited Time Offer - Free iPhone VAT Calculator
> http://berble.com/index.php/component/content/article/109
> ********************************************=20
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>
>
>
>=20
=20


[Non-text portions of this message have been removed]


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