AVR-Chat

Hello, John -

GPS does seem to be the increasing choice for time/date
data. That said, most technological countries still do have
local or regional standard time broacasts. The trend seems
to be to VLF for simple, low-cost receivers. One downside
to these is that, beyond a hundred miles or so, the signal
becomes a night-only affair. This means that the clock has
to run using its local time-base and allow periodic
updating. 

Here in the US, the change-over between standard and
daylight savings time has been pretty consistent over a 10+
year period. Clearly, you would want to be able to program
this in and have access though some kind of comm link. I
suspect that you would want  such a link, anyway, because
almost anything might happen to the sign (bolt of
lightning, anyone) and you may need to be able to reset it
or diagnose problems under more comfortable circumstances
than hanging on the side of a building!

Jim


On Thu, 15 Jun 2006 09:33:28 +1000
 John Samperi <samperi@ampertronics.com.au> wrote:
> G'day all
> 
> I'm looking into a project for an outdoor time/temp/date
> giant
> display (20" high possibly).
> 
> As the unit will be mounted on the side a multistory
> building as
> I understand, I don't think the client will want to get a
> cherry
> picker or climb a window washing lift to reset the time
> twice a
> year to cater for the dreaded daylight time changes.
> 
> So I'm looking at 3 options:
> 
> 1) Have the display connected to a computer which will be
> always
> on with a small application that will send time and date
> out every
> minute to the display via an RS485 link. This would take
> care of the
> daylight saving automatically.
> 
> 2) Have a plug in keypad somewhere at ground level.
> 
> 3) Best option-have an off air time and date signal like
> the one
> on my PVR. I know that in some parts of the world you can
> get this
> kind of signal but from my research it seems to be giving
> way to
> GPS time signal.
> 
> So my question is has anyone used some kind of receiver
> that is
> dedicated to simply receive this kind of signal? Any
> experience?
> 
> Also as far as temperature reading is concerned, a simple
> temperature
> chip on the PCB may not work because the air temp inside
> the case would
> be much higher than the actual air temp. Again any hints
> on this? I'm
> thinking along the lines of a small box with lots of
> holes and a temp
> chip inside that may work well. Again I don't have any
> experience with
> outdoor temp measurements so any guidance would be
> appreciated.
> 
> Of course I may not get the job but the research is
> interesting. :-)
> 
> 
> Regards
> 
> John Samperi
> 
> ********************************************************
> Ampertronics Pty. Ltd.
> 11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
> Tel. (02) 9674-6495       Fax (02) 9674-8745
> Email: john@ampertronics.com.au
> Website  http://www.ampertronics.com.au
> *Electronic Design * Custom Products * Contract Assembly
> ********************************************************
> 

---------------------------------------------------------------
The Think Different Store
http://www.thinkdifferentstore.com/
For All Your Mac Gear
---------------------------------------------------------------

G'day all

I'm looking into a project for an outdoor time/temp/date giant
display (20" high possibly).

As the unit will be mounted on the side a multistory building as
I understand, I don't think the client will want to get a cherry
picker or climb a window washing lift to reset the time twice a
year to cater for the dreaded daylight time changes.

So I'm looking at 3 options:

1) Have the display connected to a computer which will be always
on with a small application that will send time and date out every
minute to the display via an RS485 link. This would take care of the
daylight saving automatically.

2) Have a plug in keypad somewhere at ground level.

3) Best option-have an off air time and date signal like the one
on my PVR. I know that in some parts of the world you can get this
kind of signal but from my research it seems to be giving way to
GPS time signal.

So my question is has anyone used some kind of receiver that is
dedicated to simply receive this kind of signal? Any experience?

Also as far as temperature reading is concerned, a simple temperature
chip on the PCB may not work because the air temp inside the case would
be much higher than the actual air temp. Again any hints on this? I'm
thinking along the lines of a small box with lots of holes and a temp
chip inside that may work well. Again I don't have any experience with
outdoor temp measurements so any guidance would be appreciated.

Of course I may not get the job but the research is interesting. :-)


Regards

John Samperi

********************************************************
Ampertronics Pty. Ltd.
11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
Tel. (02) 9674-6495       Fax (02) 9674-8745
Email: john@ampertronics.com.au
Website  http://www.ampertronics.com.au
*Electronic Design * Custom Products * Contract Assembly
********************************************************

John Samperi wrote:
> G'day all

Hiya,

For the cost of an OEM GPS module (<AUD100) it is probably easier to just add it 
into the clock module & keep it all self contained.

Cheeep plastic Stevenson screens for the temp sensors are easy to come by, until 
you need to find one in a hurry for an email reply ;-), if all else fails make a 
stack of white plastic saucers with the centre cut out & 3 threaded rods with 
spacers between the saucers spaced around the outer circumfrence.

Main idea is to create a ventilated space that is out of direct sunlight and 
clear of radiation from the screen surface. The idea of the screen construction 
is to minimise the exposed area of the outer wall to sunlight.

Alternatively try the zone beneath the display although if it is wall mounted 
then you will have the measurement distorted by the warm air rising up the face 
of the building.

Cheers

Don

> 
> I'm looking into a project for an outdoor time/temp/date giant
> display (20" high possibly).
> 
> As the unit will be mounted on the side a multistory building as
> I understand, I don't think the client will want to get a cherry
> picker or climb a window washing lift to reset the time twice a
> year to cater for the dreaded daylight time changes.
> 
> So I'm looking at 3 options:
> 
> 1) Have the display connected to a computer which will be always
> on with a small application that will send time and date out every
> minute to the display via an RS485 link. This would take care of the
> daylight saving automatically.
> 
> 2) Have a plug in keypad somewhere at ground level.
> 
> 3) Best option-have an off air time and date signal like the one
> on my PVR. I know that in some parts of the world you can get this
> kind of signal but from my research it seems to be giving way to
> GPS time signal.
> 
> So my question is has anyone used some kind of receiver that is
> dedicated to simply receive this kind of signal? Any experience?
> 
> Also as far as temperature reading is concerned, a simple temperature
> chip on the PCB may not work because the air temp inside the case would
> be much higher than the actual air temp. Again any hints on this? I'm
> thinking along the lines of a small box with lots of holes and a temp
> chip inside that may work well. Again I don't have any experience with
> outdoor temp measurements so any guidance would be appreciated.
> 
> Of course I may not get the job but the research is interesting. :-)
> 
> 
> Regards
> 
> John Samperi
> 
> ********************************************************
> Ampertronics Pty. Ltd.
> 11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
> Tel. (02) 9674-6495       Fax (02) 9674-8745
> Email: john@ampertronics.com.au
> Website  http://www.ampertronics.com.au
> *Electronic Design * Custom Products * Contract Assembly
> ********************************************************

John,

Here in the States our National Institute of Standards and Technology 
(NIST, formerly NBS) provides several standard time/frequency 
transmissions for use in time keeping and frequency standardization.  We 
use a receiver/comparator to calibrate clock oscillators in frequency 
counters.  I suspect that you have a similar service provided by the 
government down yonder.  There is also a service available for world 
timekeeping but I don't know anything about it.  Here are some links:

                http://tf.nist.gov/service/its.htm
                http://tf.nist.gov/timefreq/general/links.htm
                http://www.worldtime.com/

Our NIST transmits a standard frequency signal as well as time code 
information.  I believe some of these were replaced by LORAN-C for a 
while but it appears those are now being replaced with GPS decoders.  
LORAN was the predecessor to GPS for global positioning and still may be 
used by ships at sea.

If your customer has internet access it might be just as easy to have 
his main computer collect the time information via the internet and then 
send that to your equipment.

Your temperature data is going to be a real bear.  You might think about 
sucking outside air in through an insulated duct of some sort so that 
you don't have to compensate for local thermal masses that will skew 
your readings.  If you want to add some additional spiff, you could add 
humidity since all you need at this point is one more sensor.


REB


John Samperi wrote:

>G'day all
>
>I'm looking into a project for an outdoor time/temp/date giant
>display (20" high possibly).
>
>As the unit will be mounted on the side a multistory building as
>I understand, I don't think the client will want to get a cherry
>picker or climb a window washing lift to reset the time twice a
>year to cater for the dreaded daylight time changes.
>
>So I'm looking at 3 options:
>
>1) Have the display connected to a computer which will be always
>on with a small application that will send time and date out every
>minute to the display via an RS485 link. This would take care of the
>daylight saving automatically.
>
>2) Have a plug in keypad somewhere at ground level.
>
>3) Best option-have an off air time and date signal like the one
>on my PVR. I know that in some parts of the world you can get this
>kind of signal but from my research it seems to be giving way to
>GPS time signal.
>
>So my question is has anyone used some kind of receiver that is
>dedicated to simply receive this kind of signal? Any experience?
>
>Also as far as temperature reading is concerned, a simple temperature
>chip on the PCB may not work because the air temp inside the case would
>be much higher than the actual air temp. Again any hints on this? I'm
>thinking along the lines of a small box with lots of holes and a temp
>chip inside that may work well. Again I don't have any experience with
>outdoor temp measurements so any guidance would be appreciated.
>
>Of course I may not get the job but the research is interesting. :-)
>
>
>Regards
>
>John Samperi
>
>********************************************************
>Ampertronics Pty. Ltd.
>11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
>Tel. (02) 9674-6495       Fax (02) 9674-8745
>Email: john@ampertronics.com.au
>Website  http://www.ampertronics.com.au
>*Electronic Design * Custom Products * Contract Assembly
>********************************************************
>
>
>
>
> 
>Yahoo! Groups Links
>
>
>
> 
>
>
>
>
>  
>


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

Thanks Don, I'll look into the screens or make one up.
Now that you mentioned it I think I have seen something like
what you describe.

Thanks Jim, you are really enthusiastic about the topic
with 3 replies at the same time :-)

Regards

John Samperi

********************************************************
Ampertronics Pty. Ltd.
11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
Tel. (02) 9674-6495       Fax (02) 9674-8745
Email: john@ampertronics.com.au
Website  http://www.ampertronics.com.au
*Electronic Design * Custom Products * Contract Assembly
********************************************************

> I can get RS 232 output GPS antenna (these are self contained mag 
base, 
> black units about 4"sq for around the au$80 mark) we use these for 
our 
> speed monitors in Rally cars, so they are robust.

I have managed to lock myself out of Yahoo for a few hours I think! :-(
Can you please let me know where I coud get them? Does it have time 
date output that can be accessed easily?

Don Ingram wrote:
> John Samperi wrote:
>> G'day all
> 
> Hiya,
> 
> For the cost of an OEM GPS module (<AUD100) it is probably easier to just add it 
> into the clock module & keep it all self contained.
> 
> Cheeep plastic Stevenson screens for the temp sensors are easy to come by, until 
> you need to find one in a hurry for an email reply ;-), if all else fails make a 
> stack of white plastic saucers with the centre cut out & 3 threaded rods with 
> spacers between the saucers spaced around the outer circumfrence.
> 
> Main idea is to create a ventilated space that is out of direct sunlight and 
> clear of radiation from the screen surface. The idea of the screen construction 
> is to minimise the exposed area of the outer wall to sunlight.
> 
> Alternatively try the zone beneath the display although if it is wall mounted 
> then you will have the measurement distorted by the warm air rising up the face 
> of the building.
> 
> Cheers
> 
> Don

I can get RS 232 output GPS antenna (these are self contained mag base, 
black units about 4"sq for around the au$80 mark) we use these for our 
speed monitors in Rally cars, so they are robust.

I have one outside (has been exposed for over 2 years) and is still 
running (and no I am not worried about tracking the movement of the 
house, just needed one for test and they do not work well inside, so 
extended cable)


-- 
Regards,

Kat.
---------------------------------------------------------------
  K.A.Q. Electronics     Website: www.kaqelectronics.dyndns.org
  IM: Yahoo: PinkyDwaggy MSN: katinka@kaqelectronics.dyndns.org
  For Everything Electronics 		   Phone: 0419 923 731
---------------------------------------------------------------

John Samperi wrote:
> Thanks Don, I'll look into the screens or make one up.
> Now that you mentioned it I think I have seen something like
> what you describe.
> 
> Thanks Jim, you are really enthusiastic about the topic
> with 3 replies at the same time :-)
> 
> Regards
> 
> John Samperi

For ideas on housing of temp sensor, visit local met office and they 
will gladly give you a tour (phone first as if you arrive at a time when 
they are releasing a balloon they will ignore you for 30 or so minutes 
lol. I used to work in met with radar / data reception (using the same 
parabolic antenna) was fun, Just wish I had of acquired some of the 
electronics boxes (they are cheap and disposable as we just send them 
out and never recover them (most end up in the ocean) they have a 
parachute so they land gently (to avoid injuring people / animals / 
property if they land near anything) the ones from Perth look like a 
polystyrene white 6 can cooler ;)


-- 
Regards,

Kat.
---------------------------------------------------------------
  K.A.Q. Electronics     Website: www.kaqelectronics.dyndns.org
  IM: Yahoo: PinkyDwaggy MSN: katinka@kaqelectronics.dyndns.org
  For Everything Electronics 		   Phone: 0419 923 731
---------------------------------------------------------------

samperiau wrote:
>> I can get RS 232 output GPS antenna (these are self contained mag 
> base, 
>> black units about 4"sq for around the au$80 mark) we use these for 
> our 
>> speed monitors in Rally cars, so they are robust.
> 
> I have managed to lock myself out of Yahoo for a few hours I think! :-(
> Can you please let me know where I coud get them? Does it have time 
> date output that can be accessed easily?

Yeap, Time date is in the vtg string IIRC. I will get a friend who buys 
them in bulk to give you a price :)




-- 
Regards,

Kat.
---------------------------------------------------------------
  K.A.Q. Electronics     Website: www.kaqelectronics.dyndns.org
  IM: Yahoo: PinkyDwaggy MSN: katinka@kaqelectronics.dyndns.org
  For Everything Electronics 		   Phone: 0419 923 731
---------------------------------------------------------------

I've bought about 5 GPS engines (mostly Jupiter 12) for US $ 10 to 30 on 
eBay and at ham radio flea markets.  The data string is very easy to read 
and extract the time from.

Zack

On Thu, 15 Jun 2006, Don Ingram wrote:

> John Samperi wrote:
> > G'day all
> 
> Hiya,
> 
> For the cost of an OEM GPS module (<AUD100) it is probably easier to just add it 
> into the clock module & keep it all self contained.
>

I've done something similar with an infrared remote control -- really simple 
2-signal protocol -- one to change mode and the other to change the value in 
that mode.

And if I'm not mistaken, I've been on this list for a year or more and this is 
my first post here.

Cheers,
-Neil.

On Wednesday 14 June 2006 18:33, John Samperi wrote:
> G'day all
>
> I'm looking into a project for an outdoor time/temp/date giant
> display (20" high possibly).
>
> As the unit will be mounted on the side a multistory building as
> I understand, I don't think the client will want to get a cherry
> picker or climb a window washing lift to reset the time twice a
> year to cater for the dreaded daylight time changes.
>
> So I'm looking at 3 options:
>
> 1) Have the display connected to a computer which will be always
> on with a small application that will send time and date out every
> minute to the display via an RS485 link. This would take care of the
> daylight saving automatically.
>
> 2) Have a plug in keypad somewhere at ground level.
>
> 3) Best option-have an off air time and date signal like the one
> on my PVR. I know that in some parts of the world you can get this
> kind of signal but from my research it seems to be giving way to
> GPS time signal.
>
> So my question is has anyone used some kind of receiver that is
> dedicated to simply receive this kind of signal? Any experience?
>
> Also as far as temperature reading is concerned, a simple temperature
> chip on the PCB may not work because the air temp inside the case would
> be much higher than the actual air temp. Again any hints on this? I'm
> thinking along the lines of a small box with lots of holes and a temp
> chip inside that may work well. Again I don't have any experience with
> outdoor temp measurements so any guidance would be appreciated.
>
> Of course I may not get the job but the research is interesting. :-)
>
>
> Regards
>
> John Samperi
>
> ********************************************************
> Ampertronics Pty. Ltd.
> 11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
> Tel. (02) 9674-6495       Fax (02) 9674-8745
> Email: john@ampertronics.com.au
> Website  http://www.ampertronics.com.au
> *Electronic Design * Custom Products * Contract Assembly
> ********************************************************

At 09:25 15/06/2006, Don Ingram wrote:
>John Samperi wrote:
>
>Main idea is to create a ventilated space that is out of direct sunlight and
>clear of radiation from the screen surface. The idea of the screen 
>construction
>is to minimise the exposed area of the outer wall to sunlight.
>
>Alternatively try the zone beneath the display although if it is wall mounted
>then you will have the measurement distorted by the warm air rising up the 
>face
>of the building.

You will find that any temperature sensor in, above, under, over or around 
the enclosure will read the latent heat of the wall of the 
building.   While hot air will rise along the surface of a wall, its the 
re-radiated heat of the building that will dominate your readings.

Having worked in the HVAC controls market, trying to read the ambient air 
temperature with any form of wall in close proximity; taught you that your 
readings were a function of the wall temp, not the ambient air 
temperature.  How much depended on how far away the sensor was from the 
wall and what type of material the wall was made of, think thermal mass.

I would design up your enclosure and run some experiments at ground level 
(easy reach) you should find the height up the wall not so important unless 
it its right at the top and a wind is blowing.   With some profiling you 
should be able to attain corrected measurements within 2-3degC of ambient.

Let us know how you go, sounds like fun groovy project.  If you get stuck 
for GPS send me an personal email and I can put you onto one of my suppliers.

Cheers

Matthew

What do you do for antennas?

----Original Message Follows----

From: Zack Widup <w9sz@prairienet.org>
Reply-To: AVR-Chat@yahoogroups.com
To: AVR-Chat@yahoogroups.com
Subject: Re: [AVR-Chat] Time sources in Australia
Date: Wed, 14 Jun 2006 22:42:52 -0500 (CDT)


I've bought about 5 GPS engines (mostly Jupiter 12) for US $ 10 to 30 on
eBay and at ham radio flea markets.  The data string is very easy to read
and extract the time from.

Zack

On Thu, 15 Jun 2006, Don Ingram wrote:

 > John Samperi wrote:
 > > G'day all
 >
 > Hiya,
 >
 > For the cost of an OEM GPS module (<AUD100) it is probably easier to just 
add it
 > into the clock module & keep it all self contained.
 >





Yahoo! Groups Links

Cat C wrote:
> What do you do for antennas?
> 

They are built in on the modules I use.

-- 
Regards,

Kat.
---------------------------------------------------------------
  K.A.Q. Electronics     Website: www.kaqelectronics.dyndns.org
  IM: Yahoo: PinkyDwaggy MSN: katinka@kaqelectronics.dyndns.org
  For Everything Electronics 		   Phone: 0419 923 731
---------------------------------------------------------------

At 09:55 AM 15/06/2006, you wrote:
>Cheeep plastic Stevenson screens for the temp sensors are easy to 
>come by, until
>you need to find one in a hurry for an email reply ;-),

Here is a couple but NOT CHEAP :-(

http://www.environdata.com.au/images/stories/pdf/SensorShelterSS11.pdf

http://www.esis.com.au/Monitor/SS4.doc


Regards

John Samperi

********************************************************
Ampertronics Pty. Ltd.
11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
Tel. (02) 9674-6495       Fax (02) 9674-8745
Email: john@ampertronics.com.au
Website  http://www.ampertronics.com.au
*Electronic Design * Custom Products * Contract Assembly
********************************************************

I've picked up a couple of the little "hockey puck" antennas on eBay 
pretty cheap.  I also built a couple of a turnstile antenna design for GPS 
that was published in a ham radio magazine a few years ago,

Zack

On Thu, 15 Jun 2006, Cat C wrote:

> What do you do for antennas?
> 
> ----Original Message Follows----
> From: Zack Widup <w9sz@prairienet.org>
> Reply-To: AVR-Chat@yahoogroups.com
> To: AVR-Chat@yahoogroups.com
> Subject: Re: [AVR-Chat] Time sources in Australia
> Date: Wed, 14 Jun 2006 22:42:52 -0500 (CDT)
> 
> 
> I've bought about 5 GPS engines (mostly Jupiter 12) for US $ 10 to 30 on
> eBay and at ham radio flea markets.  The data string is very easy to read
> and extract the time from.
> 
> Zack
>