LEAF SOC gauge with Nokia 6610 LCD display

Yes, we are working on using a display that includes a micro-SD card.
When we are able to write a file to that card, we will be able
to do one-bus CAN logging right "inside" the SOC-Meter.

Cheers, Gary

TonyWilliams said:

mogur said:

I'd prefer to see range expressed at a function of M/KwH which is much more of an absolute. Perhaps you could add that in parentheses after the speed if you anted to display both...

Click to expand...

Ditto... speed and m/kWh.

Click to expand...

Using a button we should be able to change to different display pages - with details like Voltage & Power.

The other thing I'd like to figure out is the "run rate" i.e. the rate at which SOC is dwindling. We could use the last 15 minutes or so to get an idea of current m/kwh going rate and derive a range better than the guess-o-meter.

I think 15 minutes will be too long.
Something more like 30 seconds is probably better.

garygid said:

I think 15 minutes will be too long.
Something more like 30 seconds is probably better.

Click to expand...

But that would change the range too quickly (like the intial Leaf range display). Yes, we will have to get to some happy medium (5 minutes ?).

BTW, is there a way to keep track of the time using the time stamp of the SOC messages ?

5 minutes sounds like a good compromise to me.

evnow said:

But that would change the range too quickly (like the intial Leaf range display). Yes, we will have to get to some happy medium (5 minutes ?).
BTW, is there a way to keep track of the time using the time stamp of the SOC messages ?

Click to expand...

garygid said:

Yes, we are working on usig a display that includes a micro-SD card.
When we are able to write a file to that card, we will be able
to do one-buss CAN logging right in the SOC-Meter.

Click to expand...

Exactly - we just need to find the right display. I had looked at some of them - either the display was too small or some other problem.

Found anything good ?

Hmmm ... may be this ...

http://www.adafruit.com/products/358

"1.8" 18-bit color TFT LCD display with microSD card breakout - ST7735R"





It is about the same size as 6610, has TFT and comes with microSD.

This looks like better value than 6610 !

Looks pretty sweet to me! Now, if it just comes in OLED.......

gascant said:

Looks pretty sweet to me! Now, if it just comes in OLED.......

Click to expand...

There is an OLED one - but it is too tiny. Just 1".

http://www.sparkfun.com/products/8538



An OLED display with SD would be great as the current consumption would be much less.

Do we REALLY care what the current consumption is? 50ma, 5ma; what real difference does it make in the overall scheme of things? It's nothing...

evnow said:

gascant said:

Looks pretty sweet to me! Now, if it just comes in OLED.......

Click to expand...

There is an OLED one - but it is too tiny. Just 1".

http://www.sparkfun.com/products/8538

An OLED display with SD would be great as the current consumption would be much less.

Click to expand...

mogur said:

Do we REALLY care what the current consumption is? 50ma, 5ma; what real difference does it make in the overall scheme of things? It's nothing...

Click to expand...

This is not for car efficiency - but for the handling ability of the AVR-CAN we are using (and the CAN bus itself).

I only want it in OLED because I used to work in that industry :lol:
Plus, you should be able to view it at almost any angle.

evnow said:

The other thing I'd like to figure out is the "run rate" i.e. the rate at which SOC is dwindling. We could use the last 15 minutes or so to get an idea of current m/kwh going rate and derive a range better than the guess-o-meter.

Click to expand...

Beating the GOM is as easy as just looking at the past 5 minutes.

gascant said:

I only want it in OLED because I used to work in that industry :lol:

Click to expand...

Then you should definitely have the Galaxy S or any other smartphone that has the OLED screen.

After starting up a long hill, or
coming onto flat after a long hill, or
reaching a flat stretch after hills, or
changing your freeway speed ...

do you really want to wait 5 minutes (perhaps 5 miles)
to get a "proper" estimate of your "new" range?

For me, I would like it in 5 or 10 seconds!

Maybe a user-set period would be good/necessary/best?

garygid said:

After starting up a long hill, or
coming onto flat after a long hill, or
reaching a flat stretch after hills, or
changing your freeway speed ... <snip>
Maybe a user-set period would be good/necessary/best?

Click to expand...

User set would be mega cool. But, I'd want it to default to about 5 minutes.

Anytime we look at the past to predict the future, we set ourselves up for some let downs. It could not be anymore proven than the current GOM. The 5 minute look back, or any look back, is only valid if the same parameters prevail, as we all know.

Not only does the future use need to match the past usage,
but the e-fuel estimate needs to be valid, and ...
our present "fuel" (SOC) ESTIMATE is NOT fully dependable.

CAUTION. This is probably why Nissan has hidden the "low end".

garygid said:

For me, I would like it in 5 or 10 seconds!

Click to expand...

We need atleast SOC # change before we can recalculate - that would set the minimum time needed.

Maybe a user-set period would be good/necessary/best?

Click to expand...

Yes - may be I can start thinking about a menu system using the LCD & 2 buttons that can be used to set up all this ?

I'll get the 2 push buttons and start working on that.

garygid said:

our present "fuel" (SOC) ESTIMATE is NOT fully dependable.

Click to expand...

Yes, I think we all get that. It's not dependable at the top or bottom. The top doesn't normally present a problem. The bottom could.

Nobody should logically plan a trip to 100% of the expected, but not fully dependable, range. But it happens, and will happen, with any car with such limited range. The affects of coming up bit short are mostly benign, fortunately.

The good news; you're much more likely to hit the projected range, than not. For those relatively few times where the driver is pushing his luck, and driving well into VLB, there also has to be the statistically infrequent chance that there is a problem with cell imbalance.

I hope that somebody will develop a method to predict a range issue. Until then, we should add a disclaimer about cell imbalance reducing range a small percentage of the time.

This Sparkfun display is the one that we have, but we have not
yet even talked to the card. Other things have taken priority.

The card is about 2 1/8" by 1 9/32" so it would fit in the SOC Project box.
However, getting to the micro SD card might be a bit difficult.
At $25, it seems like it MIGHT be a good choice to support Logging.

Apparently Sparkfun has two libraries for this display:
1. Write to and Manipulate the display (but we would need to turn
the information 90 degrees for our landscape use).
2. SD card support, to read/write files to a Fat 32 file system.

Tasks:
1. So, first is to talk to the board.
2. Measure byte rate (to SD card) to see if it is fast enough to Log
(we need about 140k bytes per second, I think)
3. Write to screen in landscape mode
4. Write binary Fat32 file to SC card.

-------------------------------

evnow said:

garygid said:

Yes, we are working on usig a display that includes a micro-SD card.
When we are able to write a file to that card, we will be able
to do one-bus CAN logging right in the SOC-Meter.

Click to expand...

Exactly - we just need to find the right display. I had looked at some of them - either the display was too small or some other problem.

Found anything good ?

Hmmm ... may be this ...

http://www.adafruit.com/products/358" onclick="window.open(this.href);return false;

"1.8" 18-bit color TFT LCD display with microSD card breakout - ST7735R"

It is about the same size as 6610, has TFT and comes with microSD.

This looks like better value than 6610 !

Click to expand...

garygid said:

This Sparkfun display is the one that we have, but we have not
yet even talked to the card. Other things have taken priority.

Click to expand...

Sounds good. First thing to figure out is how much current it draws.

Already I think 6610 draws too much current. The rs232 metal case of the CAN cable I've gets warm after a while - though nothing on the avr-can is warm to touch ...