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PeterC March 6th 13 05:20 PM

Remote temperature sensors - multiple sensors?
 
On Wed, 06 Mar 2013 11:10:55 +0000, The Natural Philosopher wrote:

I've got a brilliant remote temperature sensor. Its called RAF
Lakenheath & it tells me how cold it is outside via a widget on the
computer :-)


Would one of those fit in me garden shed?

No.

Ive got another remote temperature gauge that's also brilliant. Its
attached to the oil tank. It's supposed to tell me how much oil us
there, but below -2C it simply stops working. :-)


Prolly needs oiling.
--
Peter.
The gods will stay away
whilst religions hold sway

The Natural Philosopher[_2_] March 6th 13 07:36 PM

Remote temperature sensors - multiple sensors?
 
On 06/03/13 17:20, PeterC wrote:
On Wed, 06 Mar 2013 11:10:55 +0000, The Natural Philosopher wrote:

I've got a brilliant remote temperature sensor. Its called RAF
Lakenheath & it tells me how cold it is outside via a widget on the
computer :-)

Would one of those fit in me garden shed?

No.

Ive got another remote temperature gauge that's also brilliant. Its
attached to the oil tank. It's supposed to tell me how much oil us
there, but below -2C it simply stops working. :-)


Prolly needs oiling.

LMFAO.

Nice one.


--
Ineptocracy

(in-ep-toc’-ra-cy) – a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.


David.WE.Roberts March 6th 13 07:45 PM

Remote temperature sensors - multiple sensors?
 
On Wed, 06 Mar 2013 05:56:05 -0800, dwtowner wrote:

On Wednesday, 6 March 2013 10:03:14 UTC, Tim Watts wrote:
On Wednesday 06 March 2013 09:51 Andy Champ wrote in uk.d-i-y:



On 05/03/2013 19:27, Andrew Gabriel wrote:


I use dallas 1-wire digital thermometers around the house.


These are not wireless, and require a twisted pair




Am I the only person trying to work out how "1-wire" means twisted
pair?




Andy




The name is erroneous - a marketing gimmick - it means "1 wire for +ve
power

and data combined" - you still have a 2nd wire for ground...


There are actually three wires! Ground, data and power. Some 1-wire
devices can derive enough power from the data wire to run without the
power wire, but not all can. 1-wire refers to a single wire being used
for data/signal, unlike other hardware protocols which require data +
clock at least.

I've got multiple 1-wire temperature sensors hanging off my Raspberry
Pi. Some distros for the Pi (e.g, Occidentalis) allow 1-wire devices to
be connected to a GPIO, but I've got mine working off an I2C 1-wire bus
master, which then makes the sensors available through a file-system
interface.

dan.


....errrr.....a data wire but no clock signal wire?
So asynchronous as opposed to synchronous data?

Or is it that it is assumed that data is only going in one direction, so
the usual minimal TXD, RXD, GND (3 wire) configuration for asynchronous
serial data (without any handshaking pins) is cut down to a single data
wire plus earth?

If I remember my asynchronous communications (RS232 or V.24) which I
probably don't after all these years then the signal was a voltage on the
data line with respect to earth/ground.

I see from above a dedicated power line would be to power the remote
device if it had no power source of its own.
Taking power from the data line - not sure how this would work but I
haven't looked at data comms for some years.

Cheers

Dave R

The Natural Philosopher[_2_] March 6th 13 07:50 PM

Remote temperature sensors - multiple sensors?
 
On 05/03/13 17:31, Stephen H wrote:
On 05/03/2013 21:51, Jules Richardson wrote:
On Tue, 05 Mar 2013 19:27:01 +0000, Andrew Gabriel wrote:
I use dallas 1-wire digital thermometers around the house. These are not
wireless, and require a twisted pair to link them all, or 3 conductors,
depending if they are driven in 1-wire mode, or with a separate supply
line.


Any outdoor ones? When I briefly looked at this a couple of years ago,
IIRC the Dallas parts were suited toward only part of the potential
temperature range, so I was going to have to double up all the sensors
(one p/n for colder temps and another for hotter) and read the 'best' one
based on the time of year. I can't remember if they outright died beyond
their limits, or if it was just that they were only accurate over part of
the range.

cheers

Jules



if you happen to have every room wired up with lots of ethernet cat5
ports/sockets, you can get modules that do environmental monitoring of
server rooms and report back the temperature and humidity to a central
monitoring PC.

Googling for temperature ethernet sensor yields:

http://www.proges.com/en/plug-and-tr...e-sensors.html


http://www.audon.co.uk/ethernet_sensors/tme.html

http://www.hw-group.com/products/HWg...sensor_en.html

if you're really lucky to have PoE on your network, you may be even
luckier still to find temperature to ethernet modules that take power
from PoE which simplifies installation and setup considerably.



The audon one looks handy.

Id like that here.. to remind SWMBO to bring the hose in - especially
the nozzle thing - when it goes below freezing. That's one a year she's
broken.

By the way considering the OP was after shed monitoring, its worth
pointing out that you can trail a 100m* of CAT5 and a LV power cable
from a wall wart down under the garden easily enough inside a bit of e.g
hose or the like.

I have to say that I am more and more finding all foirms of RF doint
play nice with this house. Distances are too large and tehres to much
metal in it.

Gimme cat 5 any time.

*The length limits on CAT5 are not an issue with a SWITCH as opposed to
a HUB, because there are no collision possibilities down a single piece
of duplex cable. 10Mbps is easily achievable over that sort of length.


--
Ineptocracy

(in-ep-toc’-ra-cy) – a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.


The Natural Philosopher[_2_] March 6th 13 08:05 PM

Remote temperature sensors - multiple sensors?
 
On 06/03/13 19:45, David.WE.Roberts wrote:
On Wed, 06 Mar 2013 05:56:05 -0800, dwtowner wrote:

On Wednesday, 6 March 2013 10:03:14 UTC, Tim Watts wrote:
On Wednesday 06 March 2013 09:51 Andy Champ wrote in uk.d-i-y:



On 05/03/2013 19:27, Andrew Gabriel wrote:

I use dallas 1-wire digital thermometers around the house.

These are not wireless, and require a twisted pair



Am I the only person trying to work out how "1-wire" means twisted
pair?



Andy



The name is erroneous - a marketing gimmick - it means "1 wire for +ve
power

and data combined" - you still have a 2nd wire for ground...


There are actually three wires! Ground, data and power. Some 1-wire
devices can derive enough power from the data wire to run without the
power wire, but not all can. 1-wire refers to a single wire being used
for data/signal, unlike other hardware protocols which require data +
clock at least.

I've got multiple 1-wire temperature sensors hanging off my Raspberry
Pi. Some distros for the Pi (e.g, Occidentalis) allow 1-wire devices to
be connected to a GPIO, but I've got mine working off an I2C 1-wire bus
master, which then makes the sensors available through a file-system
interface.

dan.


...errrr.....a data wire but no clock signal wire?
So asynchronous as opposed to synchronous data?


well that depends on what is on the line.


Or is it that it is assumed that data is only going in one direction, so
the usual minimal TXD, RXD, GND (3 wire) configuration for asynchronous
serial data (without any handshaking pins) is cut down to a single data
wire plus earth?


It is a very simple very crude BUS system.

http://en.wikipedia.org/wiki/1-Wire

Not a pint to point bidirectional. Mire HPIB than serial ...


If I remember my asynchronous communications (RS232 or V.24) which I
probably don't after all these years then the signal was a voltage on the
data line with respect to earth/ground.

I see from above a dedicated power line would be to power the remote
device if it had no power source of its own.
Taking power from the data line - not sure how this would work but I
haven't looked at data comms for some years.


the data line is normally high. an 800pF cap in each slave stores
charge when the voltage goes low..

Its designed to be very minimal, pretty slow and needs a master with
most of the intelligence. In practice the master IIRC says 'hello XYZ
address' and the slave says 'here I am and this is my value' and that's IT.

Cutting all power to all devices resets them. Neat huh?


Cheers

Dave R



--
Ineptocracy

(in-ep-toc’-ra-cy) – a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.


David.WE.Roberts March 6th 13 08:35 PM

Remote temperature sensors - multiple sensors?
 
On Tue, 05 Mar 2013 19:27:01 +0000, Andrew Gabriel wrote:

In article ,
"David.WE.Roberts" writes:
At the moment I have three 'weather stations' which are an indoor
thermometer and clock and atmospheric pressure sensor, and a remote
temperature sensor.

snip
I use dallas 1-wire digital thermometers around the house. These are not
wireless, and require a twisted pair to link them all, or 3 conductors,
depending if they are driven in 1-wire mode, or with a separate supply
line.

You will need something to interface the Dallas 1-wire protocol to a
serial port or a USB-serial adaptor.
A raspberry pi can just about bit-bang the dallas 1-wire protocol with
the 1-wire driver included in the Wheezy distro (which will only do a
single 1-wire bus AFAIK, but you can have lots of sensors on it), and
that's not very expensive. (It occasionally fails to read the 1-wire
bus, but you can simply do it again when this happens.)

Before doing this I bought a bare 433MHz receiver with a view of
decoding the Oregon Scientific signal, but I gave up trying to make that
work. (I could see the transmissions on a scope, but they were very hard
to separate from noise in software, and I didn't get as far as working
out what the encoding was.)


Do you mean something like
http://www.altelectronics.co.uk/projects/p193/
which looks interesting.

Cheers

Dave R

David.WE.Roberts March 6th 13 09:19 PM

Remote temperature sensors - multiple sensors?
 
On Wed, 06 Mar 2013 19:50:49 +0000, The Natural Philosopher wrote:

On 05/03/13 17:31, Stephen H wrote:
On 05/03/2013 21:51, Jules Richardson wrote:
On Tue, 05 Mar 2013 19:27:01 +0000, Andrew Gabriel wrote:
I use dallas 1-wire digital thermometers around the house. These are
not wireless, and require a twisted pair to link them all, or 3
conductors, depending if they are driven in 1-wire mode, or with a
separate supply line.

Any outdoor ones? When I briefly looked at this a couple of years ago,
IIRC the Dallas parts were suited toward only part of the potential
temperature range, so I was going to have to double up all the sensors
(one p/n for colder temps and another for hotter) and read the 'best'
one based on the time of year. I can't remember if they outright died
beyond their limits, or if it was just that they were only accurate
over part of the range.

cheers

Jules



if you happen to have every room wired up with lots of ethernet cat5
ports/sockets, you can get modules that do environmental monitoring of
server rooms and report back the temperature and humidity to a central
monitoring PC.

Googling for temperature ethernet sensor yields:

http://www.proges.com/en/plug-and-tr...s-on-ethernet/

ethernet-temperature-sensors.html


http://www.audon.co.uk/ethernet_sensors/tme.html

http://www.hw-group.com/products/HWg-STE/

STE_ip_temperature_sensor_en.html

if you're really lucky to have PoE on your network, you may be even
luckier still to find temperature to ethernet modules that take power
from PoE which simplifies installation and setup considerably.



The audon one looks handy.

Id like that here.. to remind SWMBO to bring the hose in - especially
the nozzle thing - when it goes below freezing. That's one a year she's
broken.

By the way considering the OP was after shed monitoring, its worth
pointing out that you can trail a 100m* of CAT5 and a LV power cable
from a wall wart down under the garden easily enough inside a bit of e.g
hose or the like.

I have to say that I am more and more finding all foirms of RF doint
play nice with this house. Distances are too large and tehres to much
metal in it.

Gimme cat 5 any time.

*The length limits on CAT5 are not an issue with a SWITCH as opposed to
a HUB, because there are no collision possibilities down a single piece
of duplex cable. 10Mbps is easily achievable over that sort of length.


Don't recall saying it was for TMOAS - although that might be a
possibility.

Also, I do have a partially implemented CAT5E cabling scheme to the shed
and I also have mains power, water, and drainage.

At the moment I have an indoor and an outdoor (in the shade at the end of
the garage) temperature monitor from Tchibo which works very well but I
now want to monitor a couple of other places as well outside and two or
three places inside (but not all the time).

It looks as though a 3 sensor package from Oregon might do most of what I
want (apart from PC connection).

I think that the Oregon kit goes up to 8 channels in some cases, but
starts to get expensive.

Now rapidly expanding my required reading as I Google more stuff.

Cheers

Dave R


Andrew Gabriel March 6th 13 11:34 PM

Remote temperature sensors - multiple sensors?
 
In article ,
writes:
I've got multiple 1-wire temperature sensors hanging off my Raspberry Pi. Some distros for the Pi (e.g, Occidentalis) allow 1-wire devices to be connected to a GPIO, but I've got mine working off an I2C 1-wire bus master, which then makes the sensors available through a file-system interface.


The 1-wire bit-banging driver also gives you access via the filesystem
interface (not that I actually like that filesystem interface).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Man at B&Q March 7th 13 12:56 PM

Remote temperature sensors - multiple sensors?
 
On 6 Mar, 13:56, wrote:
On Wednesday, 6 March 2013 10:03:14 UTC, Tim Watts *wrote:
On Wednesday 06 March 2013 09:51 Andy Champ wrote in uk.d-i-y:


On 05/03/2013 19:27, Andrew Gabriel wrote:


I use dallas 1-wire digital thermometers around the house.


These are not wireless, and require a twisted pair


Am I the only person trying to work out how "1-wire" means twisted pair?


Andy


The name is erroneous - a marketing gimmick - it means "1 wire for +ve power


and data combined" - you still have a 2nd wire for ground...


There are actually three wires! Ground, data and power. Some 1-wire devices can derive enough power from the data wire to run without the power wire, but not all can. 1-wire refers to a single wire being used for data/signal,


You are confused.

unlike other hardware protocols which require data + clock at least.


There are no end of protocols that embed clock (or other timing
information) and data in the same wire.

MBQ

Man at B&Q March 7th 13 01:10 PM

Remote temperature sensors - multiple sensors?
 
On 6 Mar, 19:45, "David.WE.Roberts" wrote:
On Wed, 06 Mar 2013 05:56:05 -0800, dwtowner wrote:
On Wednesday, 6 March 2013 10:03:14 UTC, Tim Watts *wrote:
On Wednesday 06 March 2013 09:51 Andy Champ wrote in uk.d-i-y:


On 05/03/2013 19:27, Andrew Gabriel wrote:


I use dallas 1-wire digital thermometers around the house.


These are not wireless, and require a twisted pair


Am I the only person trying to work out how "1-wire" means twisted
pair?


Andy


The name is erroneous - a marketing gimmick - it means "1 wire for +ve
power


and data combined" - you still have a 2nd wire for ground...


There are actually three wires! Ground, data and power. Some 1-wire
devices can derive enough power from the data wire to run without the
power wire, but not all can. 1-wire refers to a single wire being used
for data/signal, unlike other hardware protocols which require data +
clock at least.


I've got multiple 1-wire temperature sensors hanging off my Raspberry
Pi. Some distros for the Pi (e.g, Occidentalis) allow 1-wire devices to
be connected to a GPIO, but I've got mine working off an I2C 1-wire bus
master, which then makes the sensors available through a file-system
interface.


dan.


...errrr.....a data wire but no clock signal wire?


What's wrong with that?

So asynchronous as opposed to synchronous data?


Isochronous.

MBQ



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