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backpacker3 06-09-2014 01:16 PM

OBDuino 2?
Ok so I've been doing a lot of looking around at the original OBDuino project and I'm running into a few problems first I haven't found anyone that has built one of these since ~2010. Second pretty much every use of the OBDuino has been in and ISO or CAN environment. Third most of the members who developed the OBDuino aren't really active anymore and most of the pictures and other things related to the project haven't been updated either. Fourth, I haven't found any documented use of it for VPW protocol (that I'll be working with) or any other protocol for that matter. Finally the arduino boards used are older and there are better alternative (and preassembled) boards out there for the same price or cheaper (I'll get to that later).

That brings me to the v2.0 part of this post, what I'm proposing is that using the hard work of the people that developed this project and the new improved arduino technology available we improve the OBDuino and provide updated instructions on how to build it.

From the research I've been doing I believe that the parts list would be something like this:

Arduino: for this application I think the Arduino Uno would be best these are the 2 options for that
The Arduino Uno REV 3~$30
Arduino REV 3

The Sainsmart Uno R3 ATmega328p ~$16
SainSmart Uno

OBD II Cable
You'll need this connector Sparkfun OBD II Connector (the exact assembly of the cave will vary depending on the vehicle)
And this
Nextrox® UART TTL Serial Port TO RS485 Converter Adapter MAX485 SMD SOP8 For Arduino
Plus a RS485 Serial cable also known as DB9

LCD I'll be using a graphic LCD over a character one as it will allow a few more functions
Graphic LCD

Push Buttons (any normally open push buttons will work.)

The goal is to retain all original functions of the OBDuino.

The original functions are: (taken from Wikipedia)

Fuel consumption, measured in mpg or l/100 km
Fuel used or remaining
Fuel cost
Fuel wasted while idling
Engine RPM
Vehicle speed
Tank distance
Remaining distance that can be travelled on the current tank of fuel
Engine load
Coolant temperature
Air intake temperature
Throttle position
Battery voltage
CAN status, for CAN protocol only, display TX and RX error
Displays instantaneous values, average, maximum and minimum values calculated per trip, per outing, or per tank of fuel
Menu system for configuring parameters

And add in the ability to:

View Diagnostic Trouble Codes (DTCs)
Clear DTCs
View and Clear pending DTCs

Those are just the ones I would like feel free to suggest ones you want.

Here is a Wikipedia article on OBD II Parameter IDs (PIDs) to see possible features of the OBDuino.

What do you think? Comments, ideas, and suggestions are all welcome.

backpacker3 06-09-2014 07:14 PM

Here are my goals for the project

1. It should be cheap, it has to be less than $60 under $50 would be great.
2. I want to avoid any extra interfaces like the ELM327 because of the added cost and complexity.
3. It has to be simple to assemble.
4. The parts should be easy to find.
5. Be easily compatible with all OBD II protocols e.g. Standardized parts for all protocols.
6. The assembly should be well documented and stable e.g. Pictures used that are hosted on any third party site should also be imported onto the ecomodder site when posting. That way if the link to the image changes it will still be an attachment on the site as well.

backpacker3 06-11-2014 06:29 PM

Well I've made a bit of progress so far. Here are my latest findings but first a quick shoutout to some of the guys on arduino forums for their help.

I think it's possible to connect the OBD II via a RS 485 serial cable and port. You can make your own serial cable with the obd II connector in the current parts list or buy one like this

I will most likely make one myself due to some of the things I've found researching. You'll also need a serial port like this one
Nextrox® UART TTL Serial Port TO RS485 Converter Adapter MAX485 SMD SOP8 For Arduino:Amazon:Computers & Accessories

This is important though if you're looking for a serial port you have to find one that matches these 2 criteria!!! 1 It has to be a RS 485 serial and, 2 it has to be for arduino.

I won't update the parts list yet because I'm still working on a few issues that will have to be worked out before the list is definite.

Currently the issue is that these protocols have too high of voltage for the arduino:
SAE J1850 VPW (Variable Pulse Width at 10.4/41.6 Kpbs, single wire)
ISO 9141-2 (Asynchronous serial communication at 10.4 Kbaud)
ISO 14230 KWP2000 (Asynchronous serial communication up to 10.4 Kbaud)

Once the voltage issues are sorted out I'll be able to get the parts and try this out to see if this is a real option for all protocols until then though this is a possible option. Hopefully though this will be good option for standardization over all protocols.

backpacker3 06-18-2014 06:49 PM

So I've updated the parts list I believe that will be the final one. I also updated one of the goals for the project for the price range because it's going to have to be less than 60 dollars for there to even be a point in making it. Otherwise the ultragauge is the same price, less work, and similar if not identical features. That is a big reason why I don't want to use the OBD II UART chip or the ELM327 interface they're just too expensive to be practical.

As usual any input is appreciated. I've also added a poll to get some thoughts on the project.

backpacker3 06-19-2014 06:02 PM

Well I got bored today and that's always dangerous. Anyway i may be adding this to the parts list why well by adding in an SD card slot you get the ability to log data you can also store data even without power or without using the arduino's built in memory. But if we log data you can also do things like create Speed to MPG charts Or Speed to RPM charts even monitor the throttle position. So even though it adds about 15 dollars I feel it's quite worth especially since it adds in a feature that both the scangauge and ultragauge don't have.

backpacker3 06-20-2014 05:05 PM

I've found a LCD I'm using a graphic LCD instead of the regular character ones. I've also updated the parts list accordingly.

CarbonMan 01-26-2015 06:01 PM

OBDuino project
Just wondering how you went with this project. From what I have researched I am interested in playing around with arduino hardware that could read ISO 15765 or ISO 9141. I need something that has the Arduino profile so I could use it as a shield.

The OBDuino references on google don't seem to have been updated in a while. Do you have a link to your project?


Anaerin 12-23-2015 04:28 PM

I'd love to get in on this at some point. I have an Arduino Nano (clone) and a Noritake Itron GU144X16D-7053B 144x16 graphic VFD (they were giving away a large batch as free samples some time ago) to use with it. Anyone interested in getting this up and running again?

oldtamiyaphile 12-24-2015 10:05 PM

I'd like to see an OBD unit that gives you the option of tapping into an injector wire for more accurate consumption figures.

I wonder if some algorithm to combine the AFM and injector signals would give the most accurate results yet as the MPGuino is good but not perfect.

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