External Freezer temperature controller wanted

[Brenton Spear]

I am looking for a device that you plug a freezer power cord into and then
this device into the power point. The device has a temperature probe that
you put into the freezer and it allows you to control the temperature of the
freezer independently of the internal thermostat. It simply reads the
temperature and turns the freezer on and off as required.

Anyone know where I could get one of these?

--
Brenton Spear
Email: brenton dot spear at defconsystems dot com
Web: www.HostingLegends.com
Projectors: www.ProjectorSpecifications.com
Radio Control Trading: www.RCTradingPost.com

 

[GT]

Kmart or Target. They sell all sorts of boring shit like this.

"Brenton Spear" <abuse@bigpond.net.au> wrote in message
news:bkesc7$112r5$1@ID-105680.news.uni-berlin.de...

I am looking for a device that you plug a freezer power cord into and then
this device into the power point. The device has a temperature probe that
you put into the freezer and it allows you to control the temperature of
the
freezer independently of the internal thermostat. It simply reads the
temperature and turns the freezer on and off as required.

Anyone know where I could get one of these?

 

[Rob Judd]

If such a device exists, it's a Bad Idea. Switching a compressor off mid
cooling cycle doesn't do it a lot of good.

Rob
(Son and brother of three refrigeration engineers)


Brenton Spear wrote:

I am looking for a device that you plug a freezer power cord into and then
this device into the power point. The device has a temperature probe that
you put into the freezer and it allows you to control the temperature of the
freezer independently of the internal thermostat. It simply reads the
temperature and turns the freezer on and off as required.

Anyone know where I could get one of these?

--
Brenton Spear
Email: brenton dot spear at defconsystems dot com
Web: www.HostingLegends.com
Projectors: www.ProjectorSpecifications.com
Radio Control Trading: www.RCTradingPost.com

 

[John G]

Can you please explain how ANY thermostat knows where the compressor cycle
is before it cuts the power?
--
John G

Wot's Your Real Problem?

"Rob Judd" <judd@ob-wan.com> wrote in message
news:3F6D3067.8E65C64E@ob-wan.com...

If such a device exists, it's a Bad Idea. Switching a compressor off mid
cooling cycle doesn't do it a lot of good.

Rob
(Son and brother of three refrigeration engineers)


Brenton Spear wrote:

I am looking for a device that you plug a freezer power cord into and
then
this device into the power point. The device has a temperature probe
that
you put into the freezer and it allows you to control the temperature of
the
freezer independently of the internal thermostat. It simply reads the
temperature and turns the freezer on and off as required.

Anyone know where I could get one of these?

--
Brenton Spear
Email: brenton dot spear at defconsystems dot com
Web: www.HostingLegends.com
Projectors: www.ProjectorSpecifications.com
Radio Control Trading: www.RCTradingPost.com

 

[Rod Speed]

John G <greentestatoptusnet.com.au> wrote in message
news:3f6d4e5b$0$4189$afc38c87@news.optusnet.com.au...

Can you please explain how ANY thermostat knows
where the compressor cycle is before it cuts the power?

He's basically garbled the story.

An integrated system can ensure that the motor
isnt turned on while the system is under pressure,
because its just been turned off.

Corse an addon can for example ensure that you
cant turn it on again until after a preset time off etc.

"Rob Judd" <judd@ob-wan.com> wrote in message
news:3F6D3067.8E65C64E@ob-wan.com...
If such a device exists, it's a Bad Idea. Switching a compressor off mid
cooling cycle doesn't do it a lot of good.

Rob
(Son and brother of three refrigeration engineers)


Brenton Spear wrote:

I am looking for a device that you plug a freezer power cord into and
then
this device into the power point. The device has a temperature probe
that
you put into the freezer and it allows you to control the temperature of
the
freezer independently of the internal thermostat. It simply reads the
temperature and turns the freezer on and off as required.

Anyone know where I could get one of these?

--
Brenton Spear
Email: brenton dot spear at defconsystems dot com
Web: www.HostingLegends.com
Projectors: www.ProjectorSpecifications.com
Radio Control Trading: www.RCTradingPost.com

 

[GB]

"Rod Speed" <rod_speed@yahoo.com> wrote in
news:bkjqo0$2eje0$1@ID-69072.news.uni-berlin.de:

He's basically garbled the story.

Yup


[...]

Corse an addon can for example ensure that you
cant turn it on again until after a preset time off etc.

Another way to go about it is to have seperate on
and off temperatures. For eg, turn the cooling off at
-7 degrees, but don't turn it on again until it
climbs back up to -5 degrees.

(did I get that the right way around?)


Anyway, the basic aim AFAIK is to avoid a situation
where the thing turns off when it gets down to
-7.000 degrees, and back on again when it climbs to
-6.999 degrees, and... wash, rinse, repeat... and
essentially oscillates (sp?) and blows itself and the
whole bloody thing up (and/or brings that half a cow
you had in the freezer up to room temperature and
essentially writes it all off. The dogs are really
happy when that happens, but for some reason, no-one
else is :-/ ).

G

#disclaimer.h: *celcius*, gottit?!?!

 

[Rod Speed]

"GB" <gb@sonicresearch.mailme.org> wrote in message news:3f6d762f@news.comindico.com.au...

"Rod Speed" <rod_speed@yahoo.com> wrote in
news:bkjqo0$2eje0$1@ID-69072.news.uni-berlin.de:
He's basically garbled the story.

Yup


[...]

Corse an addon can for example ensure that you
cant turn it on again until after a preset time off etc.

Another way to go about it is to have seperate on
and off temperatures. For eg, turn the cooling off at
-7 degrees, but don't turn it on again until it
climbs back up to -5 degrees.

(did I get that the right way around?)


Anyway, the basic aim AFAIK is to avoid a situation
where the thing turns off when it gets down to
-7.000 degrees, and back on again when it climbs to
-6.999 degrees, and... wash, rinse, repeat... and
essentially oscillates (sp?) and blows itself and the
whole bloody thing up (and/or brings that half a cow
you had in the freezer up to room temperature and
essentially writes it all off. The dogs are really
happy when that happens, but for some reason, no-one
else is :-/ ).

Thats a different problem to the problem with turning
the compressor on just after its been turned off for
whatever reason, while its still pressurised.

 

[GB]

"Rod Speed" <rod_speed@yahoo.com> wrote in
news:bkjuk6$2ghoi$1@ID-69072.news.uni-berlin.de:

Thats a different problem to the problem with turning
the compressor on just after its been turned off for
whatever reason, while its still pressurised.

Yah? what's the caper there? Do additional Bad Things
Happen when you do that?

G

 

[Russ]

"GB" <gb@sonicresearch.mailme.org> wrote in message
news:3f6d8add$1@news.comindico.com.au...

"Rod Speed" <rod_speed@yahoo.com> wrote in
news:bkjuk6$2ghoi$1@ID-69072.news.uni-berlin.de:
Thats a different problem to the problem with turning
the compressor on just after its been turned off for
whatever reason, while its still pressurised.

Yah? what's the caper there? Do additional Bad Things
Happen when you do that?

Well, yes - since the system is under pressure, the motor will be trying to
start against a very high load and will most likely stall - in the best case
it will trip an overload switch, otherwise it will burn out a fuse in the
windings, or it will burn out all together or trip a circuit breaker.

As for the original posters request, they might like to check out a
temperature controller such as a NAIS KT4
http://www.mew-europe.com/ac/download/datasheet/timer/kt_0207.pdf
This will accept a wide variety of temperature sensors, the simplest being a
thermocouple. While it will do complex auto-tuning PID temperature control,
it will also do simple on/off operation and you can set the hysteresis (gap
between turn off & on) to anything from 0.1 to 100 deg C - thus by setting a
healthy value, it avoids the risk of stalling the compressor.

It may be a little expensive for the application however, depending on
configuration it goes for around $200.

Russ.

 

[RM]

Someone let Rod Speed at rod_speed@yahoo.com loose on an internet
connection and the result was:

"GB" <gb@sonicresearch.mailme.org> wrote in message
news:3f6d762f@news.comindico.com.au...
"Rod Speed" <rod_speed@yahoo.com> wrote in
news:bkjqo0$2eje0$1@ID-69072.news.uni-berlin.de:
He's basically garbled the story.

Yup


[...]

Corse an addon can for example ensure that you
cant turn it on again until after a preset time off etc.

Another way to go about it is to have seperate on
and off temperatures. For eg, turn the cooling off at
-7 degrees, but don't turn it on again until it
climbs back up to -5 degrees.

(did I get that the right way around?)


Anyway, the basic aim AFAIK is to avoid a situation
where the thing turns off when it gets down to
-7.000 degrees, and back on again when it climbs to
-6.999 degrees, and... wash, rinse, repeat... and
essentially oscillates (sp?) and blows itself and the
whole bloody thing up (and/or brings that half a cow
you had in the freezer up to room temperature and
essentially writes it all off. The dogs are really
happy when that happens, but for some reason, no-one
else is :-/ ).

Thats a different problem to the problem with turning
the compressor on just after its been turned off for
whatever reason, while its still pressurised.

i dont get it....the compressor compresses, the gas does its heat pump
thing, the insides of the box (freezer / house etc ) get cold, the system is
turned off by the thermostat to prevent it getting any colder, a while later
the temp rises and it all happens again...is this not normal?

 

[Bob M]

Hi Rob,

I am curious what is meant by: "Switching a compressor off mid cooling
cycle doesn't do it a lot of good"?

I recently had to replace the thermostat on my freezer. After 19 years
of operation, it decided enough was enough and refused to turn on the
compressor any more. As a result, I lost >$400.00 worth of shopping
"bargains". During the trouble shooting process, I had to draw out a
schematic. Basically, the mains supply is connected through the
thermostat to the compressor, a very basic series circuit. The
thermostat consists of temperature sensing copper tube connected to a
diaphragm that operates a micro switch. The temperature-adjusting knob
operates a screw mechanism that varies the distance of the micro
switch to the diaphragm.

Prior to installing the replacement thermostat, I wanted to test it to
make sure it worked, as it was rather difficult to route the sensing
tube to its proper position. To that end, I mounted a thermometer
(alcohol tube type) against the sensor tube (at the end of the tube)
using plenty of thermal joint compound (stuff I use for mounting
transistor to heat sinks). I connected my continuity tester to the
thermostat to determine its state. Using a can of freeze mist, I was
able to determine that the thermostat had a hysteresis of about 8
degrees, i.e. temp rose 8 degrees, contacts closed, temp lowered 8
degrees, contact opened. I currently keep my freezer set at 4 degrees
F (it cycles between 0 and 8 F).

Any device that controls a compressor would need a certain amount of
hysteresis built into it. This, along with the thermal load (size of
freezer, type of insulation, thermal density of the contents), would
determine the "cooling cycle". The only consideration one might need
to address is the length of time required for the high and
low-pressure sides to equalize at the end of a cooling cycle. You do
not want a pressure differential across the compressor while it is
attempting to start, as this is unnecessarily hard on the motor.
Therefore, the only other issue the thermostat would need to ensure is
the minimum time required for system pressure equalization to occur.
By careful selection of the proper hysteresis, this specification can
easily be maintained.

I have since added an independent temperature-sensing device (i.e. an
alarm) that sounds a buzzer should the temperature ever rise above 15
degrees F inside my freezer (fool me once, shame on you, fool me
twice...........) It also works great as an alarm to tell the kids
when they have had the lid open too long!

Cheers from Canada!

Bob Morgoch


Rob Judd <judd@ob-wan.com> wrote in message news:<3F6D3067.8E65C64E@ob-wan.com>...

If such a device exists, it's a Bad Idea. Switching a compressor off mid
cooling cycle doesn't do it a lot of good.

Rob
(Son and brother of three refrigeration engineers)


Brenton Spear wrote:

I am looking for a device that you plug a freezer power cord into and then
this device into the power point. The device has a temperature probe that
you put into the freezer and it allows you to control the temperature of the
freezer independently of the internal thermostat. It simply reads the
temperature and turns the freezer on and off as required.

Anyone know where I could get one of these?

--
Brenton Spear
Email: brenton dot spear at defconsystems dot com
Web: www.HostingLegends.com
Projectors: www.ProjectorSpecifications.com
Radio Control Trading: www.RCTradingPost.com

 

[Rod Speed]

GB <gb@sonicresearch.mailme.org> wrote in message
news:3f6d8add$1@news.comindico.com.au...

Rod Speed <rod_speed@yahoo.com> wrote

Thats a different problem to the problem with turning
the compressor on just after its been turned off for
whatever reason, while its still pressurised.

Yah? what's the caper there? Do additional
Bad Things Happen when you do that?

Yeah, the motor can have a problem starting against the pressure.

 

[Rod Speed]

"RM" <d1111297remove@dodo.com.au> wrote in message news:3f6db5cc@news.comindico.com.au...

Someone let Rod Speed at rod_speed@yahoo.com loose on an internet
connection and the result was:
"GB" <gb@sonicresearch.mailme.org> wrote in message
news:3f6d762f@news.comindico.com.au...
"Rod Speed" <rod_speed@yahoo.com> wrote in
news:bkjqo0$2eje0$1@ID-69072.news.uni-berlin.de:
He's basically garbled the story.

Yup


[...]

Corse an addon can for example ensure that you
cant turn it on again until after a preset time off etc.

Another way to go about it is to have seperate on
and off temperatures. For eg, turn the cooling off at
-7 degrees, but don't turn it on again until it
climbs back up to -5 degrees.

(did I get that the right way around?)


Anyway, the basic aim AFAIK is to avoid a situation
where the thing turns off when it gets down to
-7.000 degrees, and back on again when it climbs to
-6.999 degrees, and... wash, rinse, repeat... and
essentially oscillates (sp?) and blows itself and the
whole bloody thing up (and/or brings that half a cow
you had in the freezer up to room temperature and
essentially writes it all off. The dogs are really
happy when that happens, but for some reason, no-one
else is :-/ ).

Thats a different problem to the problem with turning
the compressor on just after its been turned off for
whatever reason, while its still pressurised.

i dont get it....

Correct.

the compressor compresses, the gas does its heat pump thing,
the insides of the box (freezer / house etc ) get cold, the system
is turned off by the thermostat to prevent it getting any colder, a
while later the temp rises and it all happens again...is this not normal?

Yes, that is normal.

BUT, normally the compressor is turned on when
there is no pressure in the compressor, because its
been off for a while. So there isnt any backpressure
for the motor to start against. So it starts fine.

BUT, if the compressor is running, and the temperature
has not got down to what is required, so its still running,
and the power is interrupted, for a short time, when the
power is reapplied, there can be pressure in the
compressor that the motor has to try to start against
and that can be a problem when the motor isnt
designed to start against that pressure.

The fix is completely trivial, dont allow the motor to
be started after only a short off time. Ensure that
when its turned off, its off for long enough to let the
pressure dissipate thru the 'heat pump thing' so that
the motor never has to start against that backpressure.

 

[Rod Speed]

Bob M <bmorgoch@sympatico.ca> wrote in message
news:512df638.0309210656.f87019d@posting.google.com...

I am curious what is meant by: "Switching a compressor
off mid cooling cycle doesn't do it a lot of good"?

Its not the switching off thats the problem, its switching it
on again when its been switched off for only a short time,
so the compressor has to start against the backpressure.

You need to wait long enough for the pressure to bleed
away thru the expansion valve before starting it again.

I recently had to replace the thermostat on my freezer.
After 19 years of operation, it decided enough was enough
and refused to turn on the compressor any more. As
a result, I lost >$400.00 worth of shopping "bargains".

Many house contents policys will cover that.

During the trouble shooting process, I had to draw out
a schematic. Basically, the mains supply is connected
through the thermostat to the compressor, a very basic
series circuit. The thermostat consists of temperature
sensing copper tube connected to a diaphragm that
operates a micro switch. The temperature-adjusting
knob operates a screw mechanism that varies the
distance of the micro switch to the diaphragm.

Prior to installing the replacement thermostat, I wanted to test it to
make sure it worked, as it was rather difficult to route the sensing
tube to its proper position. To that end, I mounted a thermometer
(alcohol tube type) against the sensor tube (at the end of the tube)
using plenty of thermal joint compound (stuff I use for mounting
transistor to heat sinks). I connected my continuity tester to the
thermostat to determine its state. Using a can of freeze mist,
I was able to determine that the thermostat had a hysteresis
of about 8 degrees, i.e. temp rose 8 degrees, contacts closed,
temp lowered 8 degrees, contact opened. I currently keep
my freezer set at 4 degrees F (it cycles between 0 and 8 F).

Any device that controls a compressor would
need a certain amount of hysteresis built into it.

Yes, but that isnt the main problem. The main problem
that arises with compressors is when you get a short
mains failure while they are compressing.

This, along with the thermal load (size of freezer, type
of insulation, thermal density of the contents), would
determine the "cooling cycle". The only consideration
one might need to address is the length of time required
for the high and low-pressure sides to equalize at the end
of a cooling cycle. You do not want a pressure differential
across the compressor while it is attempting to start, as
this is unnecessarily hard on the motor.

Correct, and that last is the problem he was talking about.

Therefore, the only other issue the thermostat would need
to ensure is the minimum time required for system pressure
equalization to occur. By careful selection of the proper
hysteresis, this specification can easily be maintained.

It isnt just the hysteresis thats the problem, its short mains dropouts.

Large compressors just use a time delay.

I have since added an independent temperature-sensing
device (i.e. an alarm) that sounds a buzzer should the
temperature ever rise above 15 degrees F inside my freezer

I plan to run a set of 1-wire temperature sensors myself, all
connected in parallel, each with its own digital serial number.

Mainly for the beer brewing, but once you have that, might
as well do alarms for all the fridges and freezers as well.

(fool me once, shame on you, fool me twice...........)
It also works great as an alarm to tell the
kids when they have had the lid open too long!

Be interesting to see how long it takes before they kill the alarm |-)

Rob Judd <judd@ob-wan.com> wrote in message news:<3F6D3067.8E65C64E@ob-wan.com>...
If such a device exists, it's a Bad Idea. Switching a compressor off mid
cooling cycle doesn't do it a lot of good.

Rob
(Son and brother of three refrigeration engineers)


Brenton Spear wrote:

I am looking for a device that you plug a freezer power cord into and then
this device into the power point. The device has a temperature probe that
you put into the freezer and it allows you to control the temperature of the
freezer independently of the internal thermostat. It simply reads the
temperature and turns the freezer on and off as required.

Anyone know where I could get one of these?

--
Brenton Spear
Email: brenton dot spear at defconsystems dot com
Web: www.HostingLegends.com
Projectors: www.ProjectorSpecifications.com
Radio Control Trading: www.RCTradingPost.com

 

[Smiling Bob]

"Rod Speed" <rod_speed@yahoo.com> wrote in
news:bkkpc6$2qm2o$1@ID-69072.news.uni-berlin.de:

I plan to run a set of 1-wire temperature sensors myself, all
connected in parallel, each with its own digital serial number.

Ah, so you've stumbled across those too! Magic little
devices, aren't they! Have you tried them yet, or still
in the "thinking about" stage?

Mainly for the beer brewing, but once you have that, might
as well do alarms for all the fridges and freezers as well.

I always wondered how the brewing was going, after we
spent all that time off-topic in aus.aviation on the
subject. Didya Get any decent batches happening?

Bob

 

[Smiling Bob]

Smiling Bob <smilingbob@afakeaddress.com> wrote in
news:Xns93FE5E29C581Bsmilingbobafakeaddre@202.139.83.40:

Ah, so you've stumbled across those too! Magic little
devices, aren't they! Have you tried them yet, or still
in the "thinking about" stage?

aus.electronics punters in particular may be interested
to know of these. http://www.ibutton.com/

The 'one wire' thing is a tad misleading. What they really
use is one signal connection (the 'one wire') plus ground.

A range of unique-in-the-world serial-numbered devices
that do stuff like measure time, temperature, provide a
unique ID, store data. AFAIK there's one that can run
small java apps too.

Serial and parallel port interfaces are available, and
they're fairly trivial to hook up and make speak to your
choice of OS. I've had temperature ibuttons doing intelligent
things with both Windows and FreeBSD.

Bob

 

[Rod Speed]

Smiling Bob <smilingbob@afakeaddress.com> wrote in message news:Xns93FE5E29C581Bsmilingbobafakeaddre@202.139.83.40...

Rod Speed <rod_speed@yahoo.com> wrote

I plan to run a set of 1-wire temperature sensors myself, all
connected in parallel, each with its own digital serial number.

Ah, so you've stumbled across those too!
Magic little devices, aren't they!

Yeah, specially for the extreme wiring convenience.

I plan to get RJ11 phone extension cables, chop them in half,
solder the sensor on the bare end, put a bit of hotmelt glue
around the pins and then just use RJ11 socket strips to plug
them in in clusters like with the fridges and freezers in one
cluster, the beer temp sensors in another etc.

Have you tried them yet, or still in the "thinking about" stage?

Built the USB to 1wire converter Elektor kit,
got that working fine, havent yet got around to
doing the data acquisition from Access yet tho.

Mainly for the beer brewing, but once you have that, might
as well do alarms for all the fridges and freezers as well.

I always wondered how the brewing was going, after
we spent all that time off-topic in aus.aviation on the
subject. Didya Get any decent batches happening?

Yeah, got off my arse at the end of last winter, after having
collected a big collection of stubbys, 40 cartons or something.

Waited till the room temps overnight were above the minimum
specified with the kits, which was a bit of a footshot because
its a lot easier to add a bit of heat than to cool. Basically did
batches when it looked like it would be cooler than usual after
a cool change right thru the early summer last year.

Got so carried away that I made enough to last
until December a year later, December still to come.

Made 13 batches of about 23L per batch, all better
than the bought stuff I had been drinking up till then, VB.

Did one batch in the winter, basically because the kit was
going to get past the best by date before it warmed up.
That went well with a heater belt around the fermenter
and a fan heater in the smallest room it was in.

Did one cider kit too, tho thats not
quite as good as the best of the beers.

Bottled about half into the Coopers 740ml
PET bottles and the rest into the stubbys.

Did virtually all of the stubbys just reusing the
caps. That works fine, but its a bit fiddly to put
them on, so I got a proper capper and dont
plan to reuse the caps anymore. The capper
is just much quicker and more convenient.

No regrets, like with the bread machine,
I wont be going back to the bought stuff again.

Dont plan to do it with salami tho, too much work.

 

[Rod Speed]

"Smiling Bob" <smilingbob@afakeaddress.com> wrote in message news:Xns93FE5F6591529smilingbobafakeaddre@202.139.83.40...

Smiling Bob <smilingbob@afakeaddress.com> wrote in
news:Xns93FE5E29C581Bsmilingbobafakeaddre@202.139.83.40:
Ah, so you've stumbled across those too! Magic little
devices, aren't they! Have you tried them yet, or still
in the "thinking about" stage?

aus.electronics punters in particular may be interested
to know of these. http://www.ibutton.com/

The 'one wire' thing is a tad misleading. What they really
use is one signal connection (the 'one wire') plus ground.

A range of unique-in-the-world serial-numbered devices
that do stuff like measure time, temperature, provide a
unique ID, store data. AFAIK there's one that can run
small java apps too.

Serial and parallel port interfaces are available, and
they're fairly trivial to hook up and make speak to your
choice of OS. I've had temperature ibuttons doing intelligent
things with both Windows and FreeBSD.

I plan to do a bubble rate sensor using a PICAXE
too, and have it use the 1wire protocol too.

Later I'll use one of the 1wire thermostats for temperature
control too. Currently I just use a heater belt and manually
turn it off and on as required and use a termostatted fan
heater to control the smallest room it brews in and where
the cartons of stubbys are temperature controlled for the
first week after bottling in winter.

 

[Ken Taylor]

Don't keep us in suspenders - do you have a URL for these beasts?

Ken

"Rod Speed" <rod_speed@yahoo.com> wrote in message
news:bkld7j$30fm8$1@ID-69072.news.uni-berlin.de...

"Smiling Bob" <smilingbob@afakeaddress.com> wrote in message
news:Xns93FE5F6591529smilingbobafakeaddre@202.139.83.40...
Smiling Bob <smilingbob@afakeaddress.com> wrote in
news:Xns93FE5E29C581Bsmilingbobafakeaddre@202.139.83.40:
Ah, so you've stumbled across those too! Magic little
devices, aren't they! Have you tried them yet, or still
in the "thinking about" stage?

aus.electronics punters in particular may be interested
to know of these. http://www.ibutton.com/

The 'one wire' thing is a tad misleading. What they really
use is one signal connection (the 'one wire') plus ground.

A range of unique-in-the-world serial-numbered devices
that do stuff like measure time, temperature, provide a
unique ID, store data. AFAIK there's one that can run
small java apps too.

Serial and parallel port interfaces are available, and
they're fairly trivial to hook up and make speak to your
choice of OS. I've had temperature ibuttons doing intelligent
things with both Windows and FreeBSD.

I plan to do a bubble rate sensor using a PICAXE
too, and have it use the 1wire protocol too.

Later I'll use one of the 1wire thermostats for temperature
control too. Currently I just use a heater belt and manually
turn it off and on as required and use a termostatted fan
heater to control the smallest room it brews in and where
the cartons of stubbys are temperature controlled for the
first week after bottling in winter.

 

[Rod Speed]

Ken Taylor <ken123@xtra.co.nz> wrote in message
news:bklg86$34jnp$1@ID-76636.news.uni-berlin.de...

Don't keep us in suspenders

We'll have none of your depravity in here, thanks...

- do you have a URL for these beasts?

http://www.maxim-ic.com/1-Wire.cfm
is a pretty decent place to start.

Note I said decent, not indecent.

"Rod Speed" <rod_speed@yahoo.com> wrote in message
news:bkld7j$30fm8$1@ID-69072.news.uni-berlin.de...

"Smiling Bob" <smilingbob@afakeaddress.com> wrote in message
news:Xns93FE5F6591529smilingbobafakeaddre@202.139.83.40...
Smiling Bob <smilingbob@afakeaddress.com> wrote in
news:Xns93FE5E29C581Bsmilingbobafakeaddre@202.139.83.40:
Ah, so you've stumbled across those too! Magic little
devices, aren't they! Have you tried them yet, or still
in the "thinking about" stage?

aus.electronics punters in particular may be interested
to know of these. http://www.ibutton.com/

The 'one wire' thing is a tad misleading. What they really
use is one signal connection (the 'one wire') plus ground.

A range of unique-in-the-world serial-numbered devices
that do stuff like measure time, temperature, provide a
unique ID, store data. AFAIK there's one that can run
small java apps too.

Serial and parallel port interfaces are available, and
they're fairly trivial to hook up and make speak to your
choice of OS. I've had temperature ibuttons doing intelligent
things with both Windows and FreeBSD.

I plan to do a bubble rate sensor using a PICAXE
too, and have it use the 1wire protocol too.

Later I'll use one of the 1wire thermostats for temperature
control too. Currently I just use a heater belt and manually
turn it off and on as required and use a termostatted fan
heater to control the smallest room it brews in and where
the cartons of stubbys are temperature controlled for the
first week after bottling in winter.