Our climate change denial enthusiasts are still dubious about Michael Mann's "hockey stick" curve, despite the fact that that a dozen different ways of estimating past temperatures have confirmed that he got it right.
Here's yet another one.
As a graduate of the University of Melbourne, this kind of stuff shows up in my in-box from time to time.
-- Bill Sloman, Sydney
It is quite cute in that it is a fairly easily detectable shift in the proportion of magnesium in the calcite/aragonite structures. That they grow very slowly and steadily underwater in saturated conditions means they give nice long continuous records.
ISTR there are some very slow growing football sized deep ocean corals that are also in vogue for this sort of thing.
Oxygen stable isotope ratios on the carbonate gets you an independent measure of the proportion of water locked up as ice at the poles.
-- Regards, Martin Brown
I saw this subject and thought it was about a thermometer using
like that.
What a disappointment.
But I have to say, as someone new to this group the sheer volume of non-electronic design topics is oppressively off-putting. Why do people here feel so free to go off-topic?
Elijah
------ has been franticly building a killfile
r, things
Because that's the way the group has worked for the past twenty-odd years. I do have an interest in electronic temperature measurement, and "non-elect ronic" techniques frequently depend on some pretty fancy electronics to wor k.
Sloman A.W., Buggs P., Molloy J., and Stewart D. ?A microcontroller
-based driver to stabilise the temperature of an optical stage to 1mK in th e range 4C to 38C, using a Peltier heat pump and a thermistor sensor? ? Measurement Science and Technology, 7 1653-64 (1996)
The link says that the researchers rely on the Australian Nuclear Science a nd Technology Organisation to get their Magnesium/Calcium ratios, probably by X-ray fluorescence.
It's not all that off-topic.
-- Bill Sloman, Sydney
Welcome. Tell us about something cool and design-related!
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
That kind of thing is useless. Humankind dies away with as little as 10oC increase in global average., never to reappear again.
Probably because they have nothing to say about electronics.
Most of the good guys have been driven away.
Simple solution. Get a newsreader that has a plonk file. XNEWS is a good example:
Setup:
Download:
-- Science teaches us to trust. - sw
I'm very much not expert in design. I know how to solder and identify components. But I've been reading about projects using arduino, etc, and contemplating building some things for myself.
I'm interested in creating a new USB driver for an old keyboard and I'm interested in making an alarm clock with some non-standard features.
The keyboard project I think I can manage without needing to ask questions, that's simple enough for me. The alarm clock however does make me want to seek advice, and maybe this is the place for it?
I know -- in a high level handwavy sense -- that I can stick a RTC on an arduino processor and add an i2c screen, some buttons and a piezo speaker and have myself a basic clock that requires me to set the time every power-up and daylight savings time switch. But what if I want more? How do I get it to set itself from some external clock, eg one of the radios like WWVB? How do I get it to be dual powered so I can keep it plugged in most of the time and yet handle power outages with grace?
The clock is supposed to replace a device I have now. The current one works, but it's based on a platform from an out-of-business company and I know it will fail at some point. It gives me ten different alarms (three times that are the same across the week and one particular to each day) that I can set on a weekly basis, and plugs into a large tabletop button for ease in shutting it off blindly.
When looking at screens I can attach to an arduino I see a bunch of different colorful super bright LED things, some smaller less colorful LED things, and full color displays with hundreds by hundreds pixel counts. The current device uses a 480x272 full color touch screen display. It's more than I need. But I haven't decided if I should go with replicating that (probably without touchscreen) or a smaller display with more UI.
Some UI ideas:
2x20 or 4x20 character display (4 alarms each need HHMM, so that's 16 characters alone) rotary day of week knob push buttons for each of the four alarms on that day on-screen display of which alarms are set (and times of those alarms) 2x20 or 4x20 character display two button scroll forward or backward through week control push buttons for each of the four alarms on that day led lights under each button to indicate which are active"big" LED/LCD/something display that can show the whole seven days by four alarm matrix at once arrow buttons to move around display and toggle button
4x20 character display full matrix "displayed" but with scrolling buttons to move window toggle for alarm under buttonSome concerns:
I'm going to be using this half asleep at night sometimes. I don't want a blindingly bright display. I don't want a UI that is overly complicated to use. I do want the ability to quickly change from the 0720 alarm to the 0750 alarm or the ability to turn off all remaining alarms for the day.
I don't much care what the alarm sounds like, so long as it is loud enough for me to hear and not so loud as to bother my wife. I do want to be able to shut the alarm off fast. I do not want "snooze".
What advice would someone with experience with designing small electronics give me, particularly about the UI?
What off-the-shelf components can I mix in for my radio clock setting and UPS concerns?
Elijah
------ more of a software guy
"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.
Elijah
------ the unsubscribe button is a lot less work
WWVB if you're within range. I think there are off-the shelf receiver modules, but you'll possibly be learning state machines to write a decoder.
GPS is possibly an easier option.
an RTC module will have a battery to track time during power outages.
Many of these displays can also display enlarged text, some can display pixel graphics too, whe not using the UI display the time in big and the time of the next alarm (or a count-down) in small.
Perhaps use a light sensor to cue a low brightness mode, if you choose an LCD display get on with white writing on a black field as that will leak less light.
One of those lithium charging and cell protection modules, and a lithium cell. Add a boost converter if you need more voltage to run your clock, but arduino should be operable from lithium voltages.
-- Jasen.
If you can live with one that has a back light then something like a PIC
16F877 with a 32kHz watch crystal has just about enough pins to direct drive a 4 digit 7 segment display and run for a couple of years on a pair of AA batteries. The alarm and any backlight will shorten battery life. You can trim the thing to a couple of ppm accuracy in software.Mechanical design of the alarm off switch may require some thought!
-- Regards, Martin Brown
WWVB changed its modulation type a few years ago, but there should be IC decoders for the new system.
Ublox, and others make GPS modules that output a one pulse per second, along with NMEA timecode.
Doesn't Forte Agent have a kill file? Its online help pages are FUBAR!
-- Regards, Martin Brown
Yes, I believe so. I looked at it several times over the years and decided I could never figure it out so I kept searching. I am extremely happy with XNEWS.
-- Science teaches us to trust. - sw
I've had horrible luck getting reliable WWVB, but your mileage may vary. S eems 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 exp ensive, but you should check your reception first. The battery-backed RTCs like the DS3234, 3235 boast accuracies of better than 5PPM, and can run th rough a blackout, but typically can't deal with daylight saving time. And I should mention the humble AC line -- the long-term frequency is guarantee d to be 60.000 Hz, but again, no daylight saving, and obviously it can't cl eanly ride through a blackout.
To me WiFi seems the obvious solution, esp. since it gives you the option o f programming the clock with your smartphone. And for that matter, Bluetoo th + smartphone works too. Smartphone is the UI and the time reference. B ut we've designed around in a circle, because you could just use your Smart phone as an alarm clock. There's an app for that....
Just out of curiosity, where are you located?
I'm near Toronto, in a building swarming with noise from flourescent lights. All the radio bands up to 20 meters are completely blanked out due to the noise. If I go about 100 meters away from the building, I can receive the broadcase band and shortwave bands with no problem.
Despite being in a metal covered building, in a fringe area for WWVB, and swamped with noise, I have no problems receiving WWVB on two Casio Waveceptor watches, and a La Crosse wall clock.
The signals are strong enough for synchronization from midnight to 6am. That's about 0400 to 1000 UTC. You can see from the signal strength plots that about covers North America:
As long as you are not in the Atlantic provinces, you should have no problems receiving WWVB.
-- Science teaches us to trust. - sw
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.
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.
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.
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.
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.)
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
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