SOC-Meter Kit Hardware, Display, and Issues

[davewill]

Yes, miles driven would be great. I'd love to be able to integrate with an EVSE to automatically calc actual miles/KWh at the wall.

Yes! An odometer that reset on a set date per month would make it easier to log miles traveled for using either the Blink or the SDG&E bill to calculate ¢/mile, and wall to wheels m/kwh.

 

[garygid]

Maybe the GPS Date and time are on the ... AV-CAN buss?

But, you could look for it in the 6-hour charging EV-CAN log
that is posted with the CAN-Do program.

Download from www.wwwsite.com/puzzles/cando/

 

[evnow]

The most convinient thing for me would be to record on a daily (+per trip) basis all the things that I record now manually
- miles
- temperature
- m/kwh
Plus new ones
- SOC units

 

[garygid]

If we could locate those things in the CAN-messages.

What temperature do you record?

 

[evnow]

What temperature do you record?

Normally the one at the end of the drive (from the leaf dash). I've found it to be fairly accurate compared to the weather record.

 

[garygid]

That is the "ambient" temperature from the "eyebrow" display?

It is often very "wrong" at the start of driving, but it improves very slowly as the driving progresses, right?

 

[evnow]

That is the "ambient" temperature from the "eyebrow" display?

It is often very "wrong" at the start of driving, but it improves very slowly as the driving progresses, right?

Thats right.

 

[evnow]

I like the idea of having a larger LCD display - so that we can display multiple things on it.

We should look for LCD displays that are easy to interface with. What are we looking for - HD44780 based ?

I also see a lot of libraries in avrfreaks for various LCD displays. That should make it easier for us to interface to them.

 

[TomT]

One that can very easily be dimmed, or much better auto-dimming, would be nice too so that day and night was elegantly handled.

I like the idea of having a larger LCD display - so that we can display multiple things on it.

We should look for LCD displays that are easy to interface with. What are we looking for - HD44780 based ?

 

[garygid]

See if you can find an LCD that is backlit and relatively easy to read, perhaps like the one ScanGaugeII uses?

We have one LCD, from Chris, working (one line of the two).

However, we do not have a datasheet for it, which makes it slow going, and the contrast is not very good, at least so far.

The "RS232" (TTL level) serial-interfaced LED display I am using to get a usable SOC-Meter into people's hands ... can be seen, and interfaces with one TX-to-RX wire from the 2nd imbedded UART in the AT90CAN128 uP chip.

Quick and easy, and visible.
Suitable for most, at least until we get a better display.

 

[garygid]

This LED display is easy to dim under program control, but I have no ambient-light sensor.

HOWEVER, if we can find the LEAF's ambient light sensor (or dash dimming setting, or day/night setting), we might be able to use that information to dim the display.

But, it is probably not on the EV-CAN buss.

I intend to make some units with a EV-CAN/Car-CAN switch, if we can find useful information on the Car-CAN buss (like tire pressure, miles, speed, etc.).

 

[TomT]

I had a similar situation a while back and built a simple 555 oscillator that had its frequency controlled by a photo resistor. I then read the frequency in software to control the display brightness. Might we do something like that?

I like the idea of being able to select the CAN busses.

This LED display is easy to dim under program control, but I have no ambient-light sensor.

HOWEVER, if we can find the LEAF's ambient light sensor (or dash dimming setting, or day/night setting), we might be able to use that information to dim the display.

But, it is probably not on the EV-CAN buss.

I intend to make some units with a EV-CAN/Car-CAN switch, if we can find useful information on the Car-CAN buss (like tire pressure, miles, speed, etc.).

 

[evnow]

See if you can find an LCD that is backlit and relatively easy to read, perhaps like the one ScanGaugeII uses?

ScanGaugeII seems to be using a 16x2 LCD with backlight. Just like the ones on Sparkfun for $15.88.

The "RS232" (TTL level) serial-interfaced LED display I am using to get a usable SOC-Meter into people's hands ... can be seen, and interfaces with one TX-to-RX wire from the 2nd imbedded UART in the AT90CAN128 uP chip.

To use the same hardware interface we can use Serial Enabled 16x2 display.

http://www.sparkfun.com/products/9395

Serial Enabled 16x2 LCD - White on Black 5V
LCD-09395
$24.95

This is the latest evolution of our serial LCD. Included on a single board is a 16x2 LCD and an embedded circuit based around a PIC 16F88. The on-board PIC takes a TTL serial input and prints the characters it receives onto the LCD. The installed firmware also allows for a number of special commands so you can clear the screen, adjust the backlight brightness, turn the display on/off, and more.

 

[evnow]

Here is a slightly more expensive, but nicer option. 96x64 pixel resolution, 256 or 65K true to life colors Enhanced OLED screen. Simple serial interface - "Easy 5 pin interface to any host device: VCC, TX, RX, GND, RESET".

Serial Miniature OLED Module 0.96"
sku: LCD-08538
$39.95

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

 

[TomT]

I'd spend the few extra bucks and go for the nicer display...

Here is a slightly more expensive, but nicer option. 96x64 pixel resolution, 256 or 65K true to life colors Enhanced OLED screen. Simple serial interface - "Easy 5 pin interface to any host device: VCC, TX, RX, GND, RESET".

Serial Miniature OLED Module 0.96"
sku: LCD-08538
$39.95

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

 

[evnow]

I'd spend the few extra bucks and go for the nicer display...

Yes - it is pretty cool. Here is some sample code for the display.

http://metku.net/index.html?path=articles/4dsystems-oled-technology/index_eng6

 

[TomT]

Very nice! It would make the SOC look much more expensive and higher-end, in keeping with the character of the Leaf itself...

I'd spend the few extra bucks and go for the nicer display...

Yes - it is pretty cool. Here is some sample code for the display.

http://metku.net/index.html?path=articles/4dsystems-oled-technology/index_eng6

 

[garygid]

USER INPUT:

To do very much with selecting and showing other data, I need some user input, either some buttons or a touch-sensitive devce.

Two small buttons near the front edge of the top of my SOC-Meter box would fit, be very usable, and give me a lot of flexibility ... well, a LOT more than none!

So, two quite-small buttons is my next shopping item.
Any good suggestions?

 

[evnow]

Another option would be to interface your cell phone with the avr-con through bluetooth - essentially use the phone as the display device for AVR-CAN.

At this time it looks like only android devices can be easily connected as bluetooth supports serial profile.

We would just need a bluetooth board like this

http://www.sparkfun.com/products/10253
Bluetooth SMD Module - RN-42
sku: WRL-10253
$14.95

 

[TomT]

Some of the displays that EVNOW linked to had touchscreen capability. That might be an option though I didn't check the pricing to see if it made economic sense...

USER INPUT:
Any good suggestions?