OBD MPGuino gauge

[KJSatz]

Originally Posted by dcb

Yah, gotta get this project away from arduino too probably. Don't get me wrong, arduino is completely awesome, but it is for making simple tasks easy to write, not for making complicated tasks easy to maintain.

You may be aware I am an electronics n00b (just learned to solder last month, getting some introduction to the subject in my physics classes in college, reading up on it online), so salty.

But I'm inclined to say I agree.

What alternatives to arduino are there, and which ones are you guys leaning towards (both generally, such as PIC vs. AVR, and specifically)? Is there a straightforward way to interface these with (i) the LCD and (ii) the existing (or similar to the existing) OBD-II interfaces? Will we be able to decrease the cost by moving away from arduino? Are there established, efficient methods of power regulation we can use to clean up the +12v we get from the OBD-II port? Will you focus on a specific bus, such as CAN which is standard on post-2008 cars? I own a CAN car (2008 Civic) and would like to participate in the project to the best of my ability.

Sorry for the "wall of questions;" I don't mean it as an interrogation! I am simply curious and interested, both from a FE standpoint (it would be great to have an OBD OpenGauge MPG computer or whatever the next iteration would be titled) and from an educational/electronics standpoint. Thanks for all the work you all have put into this project already!

[oldbeaver]

Hi J Monroe,

But for a mechanic injected diesel engine...

I got success inputing throttle pot signal. Quite simple.

Now I need to input rpm from the engine.
I have a variable reluctance sensor in the RD28 diesel engine, which send a analog signal.
Then, I input that signal to a LM1906 ignition & tachometer driver. This signal becomes square and I drive my VDO analog tacho with it.

However, when I try to input that signal to an analog input pin on a Arduino clon, to make calculations, there are some numbers coming on the display, but no response to pressing the throttle.

Can you help with that? What is the correct way to input such signal to a Arduino circuit?

Maybe a simple rpm input routine will help.

Should I use a digital input instead?

Old Beaver

Originally Posted by jmonroe

Anyone interested in developing an OBD Arduino based fuel economy gauge should post here. So far, I have been working on one based around an ELM323 OBD to RS232 adapter. Some previous discussion on this was on the other thread (http://ecomodder.com/forum/showthrea...ge-1428-9.html)

Currently, I was able to connect to the ELM and send it commands. However, when sending OBD commands (010c), the response is "ELM INIT:...>" without ERROR or OK and no real data is received.

[dcb]

Originally Posted by KJSatz

What alternatives to arduino are there, and which ones are you guys leaning towards (both generally, such as PIC vs. AVR, and specifically)?

Short term it looks like a plain atmega168/328 avr is a good choice with avr-gcc. It has all been sorted out already and shares much in common with the atmega8 used in the motor controller project, as well as with the mpguino, and the arduino. So that means less futzing and more productive time, but decoupling from arduino will mean even less futzing with version issues and random cpu upgrades.

I have looked at a PIC, PIC18F4580-I/P , specifically because it has CAN onboard and comes in a through hole. But I'm a long way from doing anything interesting with it as it is a completely different platform. I wouldn't expect to inflict the inner details on the general ecomodder population.


P.S. Beav, that thread was 10 months old.

[Froggy]

Just got the Arduino Duemilanove board, LCD (16x2) and assorted goodies... Except for the 'in transit' cable I am ready to make the OBDuino...

Haven't done any soldering yet, but instead just playing with LEDs and writing code. Just having fun - stalling maybe... I am not looking forward to soldering that little MC33290...

[Magister]

It's not easy to solder the 33290, use a "3rd hand", a small tip on your iron, low temp, and it should go.
I used 28AWG or 30AWG wire and just put a small bead of solder on a pin then touch with the wire/iron a few tenth of second.

[Froggy]

Finished up most of the wiring (no backlight hooked up yet) and I can't get any data from the K line...

I tried both version 127 of OBDuino, and 131 of OBDuino32k with the same results. ISO 9141 fails in initialization (a time out error).

Is the little MCZ33290 chip easy to blow? Everything looks like it's connected correctly, but it's hard to tell. I suppose I will test for shorts and bad connections...

The unit is powered OK from the car (Toyota Matrix 2007), but no RX/TX occurs. Sigh...

[Magister]

I am wondering if the 07 Matrix is ISO or CAN?
Also I doubt the 33290 is easy to blow, it's a nice little piece of electronic (containing about 75 transistors) used in a lot of diag tool.

Revert he TX/RX pins maybe? I don't remember if it was inverted or not in the diagram :-/

[Froggy]

I looked at the pinouts for the Matrix's OBD II
both grounds are there, the K and L lines and power are all there. (It also has pins 12 and 13, but not the CAN pins????)

So it 'should' be ISO compliant.

I will check the TX/RX pins...

Edit: the RX and TX pins are correct according to the data sheet for the chip.
I also checked the pin voltage on pin 7 of the OBDII. 4 Volts according to my voltmeter. So it is active.

Edit 2: Just resoldered all the points on the port circuit board. No change. The ISO init still fails.

[Mart]

I have the exact same issue ( ISO and subaru WRX STI) using OBDuino32k.

I am using a serial LCD (softwareSerial).

I just made a quick test using the serial port and notice that the TX and RX light are blinking... but they are not blinking when I use OBDuino32k.... might be due USB vs No USB.

I have power but iso_read_byte() always return 0 so apparently there is no TX/RX. I tried swapping TX/RX but nothing as well. Anyone can help us?

thanx

Mart

Originally Posted by Froggy

Finished up most of the wiring (no backlight hooked up yet) and I can't get any data from the K line...

I tried both version 127 of OBDuino, and 131 of OBDuino32k with the same results. ISO 9141 fails in initialization (a time out error).

Is the little MCZ33290 chip easy to blow? Everything looks like it's connected correctly, but it's hard to tell. I suppose I will test for shorts and bad connections...

The unit is powered OK from the car (Toyota Matrix 2007), but no RX/TX occurs. Sigh...

[Mart]

Quick update. Subaru ECU is made by DENSO. I quickly implemented a cheesy KWP2000 fast init style as specified here: prj.perquin.com and I was able to get a response from the ECU but the rest of the obduino32k.pde doesnt seem to work. I am suspecting timing issue but I am also wondering how those universal obd-ii works (timing wise) since they have to deal with multiple ECU from multiple companies...

Mart

Originally Posted by Mart

I have the exact same issue ( ISO and subaru WRX STI) using OBDuino32k.

I am using a serial LCD (softwareSerial).

I just made a quick test using the serial port and notice that the TX and RX light are blinking... but they are not blinking when I use OBDuino32k.... might be due USB vs No USB.

I have power but iso_read_byte() always return 0 so apparently there is no TX/RX. I tried swapping TX/RX but nothing as well. Anyone can help us?

thanx

Mart