OT: A new thermometer for temperatures in the past....

In sci.electronics.design, Jim MacArthur <jimbmacarthur@gmail.com> wrote:
I\'ve had horrible luck getting reliable WWVB, but your mileage may
vary. Seems like the maker space is gravitating to a WiFi solution --
Google WiFi RTC Arduino. GPS was mentioned, and the Arduino GPS
modules aren\'t too expensive, but you should check your reception
first.
Click to expand...

I have wifi on the current device, but the placement means I don\'t get a
good signal. I expect I\'d get a poor GPS signal in that spot. I admit I
haven\'t checked WWVB, reception there either, but radio antennas are
simple and cheap.

This is San Francisco, in a post-earthquake house, with real plaster
walls (not sheetrock). The wifi airspace is very busy, I can see
thirteen SSIDs right now. Writing an arduino UI for selecting an SSID
and authenticating to it seems like a pain in the neck. Based on past
experience, the wifi base station will be replaced at least once before
expected end of life of the alarm.

And I should mention the humble AC line -- the long-term frequency is
guaranteed to be 60.000 Hz, but again, no daylight saving, and
obviously it can\'t cleanly ride through a blackout.
Click to expand...

Yeah, I know AC is good as a digital pendulum for a clock, but it is not
a source for setting a clock. I\'d rather have a device that can drift
a few seconds over the course of a week, if it can accurately reset
itself at least that often, then have a device that can keep perfect
time over the course of a week, but can\'t reset itself at all.

To me WiFi seems the obvious solution, esp. since it gives you the
option of programming the clock with your smartphone.
Click to expand...

Usually I do not have my smartphone at my bedside. I most certainly
_do not want_ to have to pick up my smartphone to turn off off the alarm
set for 0720 if I\'m getting up on my own at 0715, which is a real use
case for me.

But we\'ve designed around in a circle, because you could just use
your Smartphone as an alarm clock. There\'s an app for that....
Click to expand...

There\'s no app for alarm clock that works for the phone in another room
with the restriction of \"wake me, not my wife\". No bright lights at all,
and dim light that turns off easily (or automatically, quickly) also are
constraints for not bothering the person on the other side of the bed.

(Old house, few outlets. I\'ve been opting for charge phone not at
bedside for a while now.)
 
Jim MacArthur <jimbmacarthur@gmail.com> wrote:

Just out of curiosity, where are you located?


As long as you are not in the Atlantic provinces, you should have no
problems receiving WWVB.
--

Boston, so yeah, the Atlantic provinces. And I\'ve seen the coverage
maps too, but I\'m not the only Bostonian who\'s had rotten luck getting
WWVB.
Click to expand...

GPS?

My friend has a cellphone and connects to WiFi. This gives her the time
through whatever WiFi connects to.

I connect to DSL through a NAT router. So I have the time to about 1
second.

A good GPSDO (GPS disciplined Oscillator) can get to about 1 picosecond
plus diurnal cycle effects.

So you have about 12 orders of magnitude to play with.

--
Science teaches us to trust. - sw
 
There\'s no app for alarm clock that works for the phone in another room
with the restriction of \"wake me, not my wife\". No bright lights at all,
and dim light that turns off easily (or automatically, quickly) also are
constraints for not bothering the person on the other side of the bed.

(Old house, few outlets. I\'ve been opting for charge phone not at
bedside for a while now.)
Click to expand...

More than a decade ago, a friend asked me to design an alarm clock with a few features similar to what you describe. I threw something together in an hour, and he rejected it for one of the reasons you\'ve mentioned (display too bright, or whatever). So I tried again. And failed. And a decade later, I still like to throw a few hours at the problem, because it\'s so absurdly simple that I can\'t solve it.

I would like to suggest a feature for your clock, though: DMX. My friend asked for, among other things, a dawn simulator which would fade up room lights. I found, after several iterations, that theatrical lights are cheaper than anything I can build:

https://www.sweetwater.com/store/detail/SlimPAR56--chauvet-dj-slimpar-56-rgb-par

They\'re controlled by DMX, which is basically just async over RS485, so it\'s trivial to through a spare UART into an RS485 transmitter for a couple of bucks, just in case. Of course, you have to run unsightly DMX cables around the room...

 
On 30/10/2020 19:58, Eli the Bearded wrote:
In sci.electronics.design, Steve Wilson <spam@me.com> wrote:
John Larkin <jlarkin@highland_atwork_technology.com> wrote:
Eli the Bearded <*@eli.users.panix.com> wrote:
What a disappointment.
Most of the good guys have been driven away.
Simple solution. Get a newsreader that has a plonk file. XNEWS is a good
example:

\"Muggers driving people away from the neighborhood? Simple solution. Get
some body armor.\"

I have a killfile, now. Being forced to create one is not a welcoming
experience.
Click to expand...

They have been necessary on Usenet ever since it stopped being an
academic network for mostly technical exchanges. Usenet civility went
seriously downhill at about same time that AOL came on the scene.

They were not called Arseholes On Line for nothing.

--
Regards,
Martin Brown
 
On 02/11/20 13:48, Martin Brown wrote:
On 30/10/2020 19:58, Eli the Bearded wrote:
In sci.electronics.design, Steve Wilson  <spam@me.com> wrote:
John Larkin <jlarkin@highland_atwork_technology.com> wrote:
Eli the Bearded <*@eli.users.panix.com> wrote:
What a disappointment.
Most of the good guys have been driven away.
Simple solution. Get a newsreader that has a plonk file. XNEWS is a good
example:

\"Muggers driving people away from the neighborhood? Simple solution. Get
some body armor.\"

I have a killfile, now. Being forced to create one is not a welcoming
experience.

They have been necessary on Usenet ever since it stopped being an academic
network for mostly technical exchanges. Usenet civility went seriously downhill
at about same time that AOL came on the scene.

They were not called Arseholes On Line for nothing.
Click to expand...

Just so.

1993 was know as the \"year that September never ended\".
 
Re WWVB reception issues, I googled around and found this:

https://www.universal-solder.ca/product-category/atomic-clock-radio-receiver/everset-es100-wwvb-bpsk/

This boutique chip is apparently the only commercially available single-chip solution that takes advantage of WWVB\'s recently-introduced phase-shift keying. It\'s absurdly overpriced, but I might have to buy one anyway, just to see if it works.
 
In sci.electronics.design, Jim MacArthur <jimbmacarthur@gmail.com> wrote:
Re WWVB reception issues, I googled around and found this:

https://www.universal-solder.ca/product-category/atomic-clock-radio-receiver/everset-es100-wwvb-bpsk/

This boutique chip is apparently the only commercially available
single-chip solution that takes advantage of WWVB\'s
recently-introduced phase-shift keying. It\'s absurdly overpriced, but
I might have to buy one anyway, just to see if it works.
Click to expand...

Agreed that is expensive for what it is, but I\'m tempted.

Elijah
------
would have expected more options
 
Wait a sec. Modern FM radio ICs can get RDS (RBDS) and one of the RDS messages is the time. But when you look at COTS FM clock radios, even those that receive RDS, the time-setting ones _also_ receive WWVB. Is that because the Clock Time (CT) RDS message isn\'t widely supported? Because if it is, then why not use it?
 
On 05/11/2020 14:20, Jim MacArthur wrote:
Wait a sec. Modern FM radio ICs can get RDS (RBDS) and one of the
RDS messages is the time. But when you look at COTS FM clock radios,
even those that receive RDS, the time-setting ones _also_ receive
WWVB. Is that because the Clock Time (CT) RDS message isn\'t widely
supported? Because if it is, then why not use it?
Click to expand...

Unclear. I have a DAB radio that fails to update its time at all.

It was an UK DAB radio bought as an early adopter before it was obvious
just what a lousy encoding schema they had used. DAB+ is much better.

My favourite in this line of weird design decisions driven by adding a
new feature vs benefit was a computerised telescope drive where the RTC
crystal was not properly loaded with the right capacitance and so ran
fast by about 15 minutes a month. The solution was not to add the right
capacitor network but to add the novelty of a GPS feature so that the
user no longer needed to input his present location or set the time. The
older models could cope with storing three regular observing sites.

Unless you were observing from the back of a rapidly moving flatbed
truck or out of a 747 in flight this was more than a little overkill.

--
Regards,
Martin Brown
 
In sci.electronics.design, Jim MacArthur <jimbmacarthur@gmail.com> wrote:
Wait a sec. Modern FM radio ICs can get RDS (RBDS) and one of the RDS
messages is the time. But when you look at COTS FM clock radios, even
those that receive RDS, the time-setting ones _also_ receive WWVB. Is
that because the Clock Time (CT) RDS message isn\'t widely supported?
Because if it is, then why not use it?
Click to expand...

That would be okay by me -- IF I can easily pick what station to sync
to. On my previous car, the car radio used that and I found some
stations were less accurate than others. In particular the scrappy, low
budget stations were not a good choice.

(On my current car, I don\'t know what it syncs to, but I suspect GPS.)

Elijah
------
at least the entertainment clock does, the dash clock is manually set
 
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