Will the LED clock adjust itself in the Prius after Daylight Savings Time?

<div class='quotetop'>QUOTE(qbee42 @ Nov 2 2007, 04:20 PM) [snapback]534134[/snapback]</div>

I disagree. The NAV has a dedicated compass screen (without a map) that shows the direction of the car.

 

Re: gps for time...

While gps signals do include the time, it is in GMT, and not particularly useful for daylight saving transitions, especially since the rules are inconsistent worldwide [*] and tend to shift with local legislation. so, they could use gps to get accurate time, but the owner would still need to set the timezone, as well as let the car know every time daylight saving started and every time daylight saving ended.

[*]
e.g. both Israel and Palestine do daylight saving time, but the dates they shift are legislated each year and all over the map. The only thing you can say with _certainty_ is that the two _won't_ shift on the same weekend.

 

<div class='quotetop'>QUOTE(IsrAmeriPrius @ Nov 2 2007, 05:44 PM) [snapback]534118[/snapback]</div>

I don't have Nav, but I have the Homelink rearview mirror.
They should put a compass there...

 

I have notice there is no altimeter or accelerometer to determine G-forces or a rate of climb indicators, inclinometer or even a mass spectrometer but maybe that's a good thing. How many cars are fitted with a compass? I guess if it was a landyacht you might want one.

I wouldn't mind an ICE temperature gauge, thats all, maybe I could move the external temperature pickup? I wonder what the range of the outside air temp gauge is?

 

<div class='quotetop'>QUOTE(patsparks @ Nov 2 2007, 11:55 PM) [snapback]534222[/snapback]</div>

Lots of cars have a compass, long before GPS became the "in" thing. My other car has one.
I came to rely on it quite a bit when driving around unfamiliar territories. The manufacturer of the
Prius' homelink mirror has an upgraded model that includes a compass. Really nice, but I can't
justify shelling out several hundred bucks just for that one extra feature.

I've also been thinking of adding a barometer, dual thermometer, and altimeter to the car. Either that
or getting a multi-function watch that can do the same. I'm just not fond of wearing watches...

 

OMG, its just a clock fer cryin' loud. Adjust it and move on.
By the way, in some Lexus' with nav will automatically change the time, but we're having some issues with the original LS's with NAV that were programmed to change earlier (not November 4th)

 

<div class='quotetop'>QUOTE(IsrAmeriPrius @ Nov 2 2007, 07:29 PM) [snapback]534136[/snapback]</div>

Nope, doesn't work that way. The dedicated compass screen is derived from the GPS, not from any magnetic information. A GPS derived compass works by looking at the last few position fixes, and draws a line through these points. The system then assumes the car is pointing in the direction of this line, which is a good assumption under normal driving conditions.

As a contrived example of a situation where a GPS compass doesn't work, think of a Prius sitting sideways, pointing to the left, on the back of a flat-bed truck. The truck is driving due north. A person sitting in the Prius looks at the GPS compass display and sees that it shows the Prius pointing north, even though it is actually pointing west. The GPS system can only determine the direction of travel, not which way the Prius is pointing.

With a car, a GPS compass works pretty well, since the car is almost always pointing in the direction of travel. It's not as good in a car or boat, where there is often some angle of crab. The place where a GPS compass in a car runs into trouble is when you make a very tight turn, such as in a parking lot. After making a tight turn, it can take a hundred yards or so for the GPS compass to catch up. Try it some time as an experiment.

A similar thing happens with GPS speed readings. Just as GPS provides no inherent compass information, it also fails to provide any inherent speed information. GPS is a positioning system. All it does is allow a receiver to determine position and time. Any other information is derived from position and time readings. For example, speed is determined by calculating the distance between two position readings, and dividing by the elapsed time between the readings. This assumes a straight line was traveled between the readings. If you travel in a circle between GPS fixes, the GPS system will show a speed of zero, since both fixes will be taken at the same place, so the calculated distance traveled will be zero. This is normally not a big deal, since most GPS receivers update fairly often, but it's important to understand how the system works to avoid pitfalls.

Tom

 

It's no big deal to manually change the time for DST. I like it better that way. I got one of those "SmartSet" alarm clocks that was programed to adjust for DST thru the year 2099. The only problem was the Feds changed the dates for DST and the programing is all wrong. I still have to change it manually anyway.

 

<div class='quotetop'>QUOTE(qbee42 @ Nov 3 2007, 12:54 PM) [snapback]534342[/snapback]</div>

Do you know for sure that the Prius GPS has no compass? There definitely are GPS units that have a built-in compass as an added feature (I have one). It would be interesting if someone actually were to carry out the Prius-on-a-flatbed experiment or one like it; I think a car ferry might be the easiest. . .

 

<div class='quotetop'>QUOTE(Betelgeuse @ Nov 3 2007, 04:54 PM) [snapback]534382[/snapback]</div>

It's easy to see. Just do a tight turn in a parking lot and watch the GPS map try to catch up. Most GPS units with a integral compass are hand held or dash mount units. You have to get the flux sensor up and away from all of the ferris metal in the car.

Tom


<div class='quotetop'>QUOTE(ostrich @ Nov 2 2007, 07:37 PM) [snapback]534140[/snapback]</div>

So called "atomic" clocks have the same problem. They need to be told the time zone and whether to use Daylight Savings.

Tom

 

<div class='quotetop'>QUOTE(qbee42 @ Nov 2 2007, 07:20 PM) [snapback]534134[/snapback]</div>

Well, it is *slightly* better than that. It has a gyro too, so it can keep track of turns, say on a ferry. I agree that if you back up, you are SOL for directions, and of course the gyro does not successfully do dead reckoning forever without addional info.

But about the clock; I find this irritating too. At least the Nav system on a Gen3 Prius does use the GPS time if you ask for time of arrival at the destination. Why can't they put the time out on the bus for the clock display! Aaaagh!

The good news is that the digiclock on the new Prius is reasonably accurate. Not true of the one in my Gen2 (2002) Prius, which I have to reset ever couple weeks if I want it synchronized with radio shows.

 

<div class='quotetop'>QUOTE(qbee42 @ Nov 3 2007, 10:54 AM) [snapback]534342[/snapback]</div>

Since I rarely travel in my Prius while it is sitting sideways on the back of a flat bed truck, the GPS compass works for me just fine.

Yesterday, after I wrote the other message, I went to pick my daughter at her volunteer work. At home, I park in the garage facing west. I backed out (eastbound) making a 90 degree turn to the north, so that the car faced south. I then drove south for about 100 yards and turned left onto an eastbound twisting road. I was almost a mile away from home before the GPS indicator finally went on. In the interim, the compass showed my direction of travel, ranging from southeast to north-northeast, with sufficient accuracy for my needs.

It really does not matter to me how the compass works as long as it serves my purposes.

 

<div class='quotetop'>QUOTE(Duane @ Nov 2 2007, 07:08 AM) [snapback]533793[/snapback]</div>

Actually, I like the fact that it's a manual set clock. That way if some Bozo decides to change the DST rules we don't have to get a software update...

 

<div class='quotetop'>QUOTE(rfred @ Nov 4 2007, 11:51 AM) [snapback]534493[/snapback]</div>

Agreed. It isn't that hard, you don't even need to change the minutes.

 

Re: "atomic" clocks. If they're using NIST's WWVB broadcast, they will adjust for DST correctly because WWVB includes DST information. It also flags leap years and leap seconds.

You still have to set your local timezone, and override the DST function if (like me) you're in an area that doesn't observe DST.

 

<div class='quotetop'>QUOTE(bariswheel @ Nov 2 2007, 04:43 AM) [snapback]533789[/snapback]</div>

You figure it would most likely be manual, since there's no provision to set your time zone on the MFD.
It'd be nice if it updated say from radio signals, since now you can get the station name and current song from the radio to show up on your MFD - how about capturing the date and time also? But then that's where atomic clocks come into the fray.

 

Why not just a time sync off RDS?

 

The clock is just a dumb LCD clock, similar to your wristwatch but simpler. It's independent of the MFD and has no way of setting a date, so there's no way for it to know about DST.

The MFD does have a way to set the timezone if you have navigation -- it's in the nav settings. This affects the ETA display, but nothing else as far as I know.

As we've been talking about in another thread, the cell phone call log seems to be hardcoded to EST. I'm guessing the calendar also changes dates at 0000 EST too.

 

<div class='quotetop'>QUOTE(patsparks @ Nov 3 2007, 09:39 PM) [snapback]534501[/snapback]</div>

And it gets even easier than that. Like analog clocks, the Prius LED clock doesn't have that famous AM/PM issue. So you only have to scroll 1 hour or 11 hours.

 

<div class='quotetop'>QUOTE(qbee42 @ Nov 2 2007, 05:19 PM) [snapback]534080[/snapback]</div>

Yes, but I don't recall a way on the Nav system to have it show that super accurate time. In fact, we usually use it in the "time of arrival" mode, and notice that it does not sync well with the stupid cheapo in-dash clock.