Darell's first Prius journey and...

GPS units are not designed to give instaneous speeds. the only way they can determine speed is to compare two different static readings and determine the distance traveled in that time and then calculate speed based on those readings. the calculation will only be an average speed so GPS will never have true speed readings. now if you were to maintain a constant speed, a GPS can do a fair job.

also, by all accounts, my GPS and my Prius speedometer match all the time. i dont think i have ever seen the two vary by even 1 mph.

 

Well, you'll have to put together a list of what module goes where.... I hope they will all be snapin..... maybe we can help you market them......
I have two prius's I will be stocking so well see what all that adds up to.
I love LED's.... what type are you using?... I have a 4 watt inova light that has the luxeon Star LED with lithium rechargable... really nice!... I don't suppose yours will have those... they are a bit spendy....

Anyway... maybe you could market them to Toyota... that would keep you busy!.... otherwise... just PC could keep you hopping... esp with 11K members strong.

 

Our observation is same as yours.
The speedometer and odometer are calibrated differently.
Our Japanese Prius speedometer is adjusted to meet the ECE Regulation No.39 and displays +3 km/h from actual speed.
http://www.unece.org/trans/main/wp29/wp29regs/39rv1e.pdf

The odometer error was within 0.3% by our tests.

Ken@Japan

 

Wow.. your right.. I forgot thats the way they look when they're out in the open.... are they one watters?

 

Perfect.. if they dim you may need a way to make them bright again.....

maybe when they dim we could hit the button to restore it to full brightness again if we are still using it!... the dimming would simply act as a warning that its getting ready to shut off.
At only 1 watt.. might as well bump the time out to an hour or so.......

Your right.. they get very hot.... at least my 4 watter does...

and they give tons of light.....

I have already left mine on twice forgetting to turn it off after running out in the dark to do something.......

Maybe before you put them out you can make a poll... to see what folks really want.

Of course the more options the better, but that drives the price up.

Well, not everybody will want to give big bucks to replace a bulb that is still working, but I for one already gave alot to have high tech... I would buy the luxeon star leds.... I really like the frequency of white they give off.... "white bright"... those are pretty dim that presently come stock in the prius.
It would be a once in a lifetime purchase.

We went to go get an opposum in the backyard the other day so I got my little inova 4 watt light to blind him... my son in law laughed when he saw my little 8 inch flashlight... I told him to close his eyes and I would shine it in his eyes, so he did... it still blinded him!

I am already reading how they really shaft you for a normal bulb replace... Of course that won't last... but the prius has been out awhile, you think it would be cheap by now to replace a bulb.

Anyway.. I'm in!... I"m going to beddy...

 

Although I agree that most GPS devices only give an update once every second, and thus are a bit behind on showing the speed, it doesn't calculate the speed the way you thinnk it does. Actually, for speed calculation it uses the Doppler-effect: as you approach something that emits a frequency (audio, radio etc) as you move towards it, the frequency appears to be higher, depending on your speed. (Like a train blowing it's horn, when it comes in your direction, the tone is high, but when is passes you, the pitch will drop). On a constant speed, it's very accurate.

 

I was under the impression they only updated once every 2 sec. but then again my GPS (Holux BT-230) is 1.5 years old. Therefore you are always aleast 2+ secs behind your actual speed. On the interstate my speedo reads 59 and the GPS reads 60. Wish I had tenths maybe I will set the Prius to KPH for a little more accuracy.

Wildkow

 

Would it be more cost effective or easier to design if you run them direct drive, with a resistor?

 

i have a holux BT 231 and it updates 5 times /sec. however, the information is interpted by my Mac which only updates the information once per second. (that is an improvement since the previous update rate of once per 15 seconds (or worse...forget now) made its use with Route 66 mapping software useless for turn by turn directions)

if im not mistaken, yours updates more than once per second also. when i was in the market to purchase mine, i referenced a couple of real good sites that had field comparison tests.

my only requirements was decent battery life (didnt matter since most come with car chargers) bluetooth interface (wanted the wireless) and ability to get good signal lock.

the holux BT 231 rated very high in multiple sat reception and accuracy. the elevation accuracy is not great (none of them were) mine is probably about +/- 100 feet

 

My garmin quest updates position and all the other running figures
once per second. Its calculated *speed* steady-state lags the
Prius speedo by about half an MPH, and yet the GPS's calculated
travel *distance* tends to run slightly higher than the Prius odo.
Per what Ken said, this makes sense if the Pri is doing two different
methods for speedo and odo; I would sort of assume that the GPS is
basing all of its displays from a single source. I haven't tried
to match any of this to highway mileposts yet...
.
Side thought: hmm, this is spawning a lot of internal sub-threads.
Maybe the LED discussion and the speed/dist/GPS discussions should
be split out... darell, you could probably even work yourself into
the "sponsored sales" section or whatever it is with some of these
LED toys because it sounds like PC could be a market for you!
.
_H*

 

I felt funny about taking it this direction too, but since its your thread!....
If you branch off, I'll be glad to continue discussion somewhere else.

 

Nice pics!...... Are you having any problems with heat when left on for a while?