Any interest in developing an open source fuel economy gauge/computer? - Page 15 - Fuel Economy, Hypermiling, EcoModding News and Forum

TomO · 04-25-2008, 03:18 PM

I really appreciate the work everyone is doing for this project.

I also feel super compelled to offer some time for this projects as I can lend some excellent soldering/assembly skills since I majored/degree'd in Electronics repair.

I do have about one month of time that I can set aside for helping someone out with assembling/soldering, but at the end of May, I move back home with my kids and wife and will most likely lose out on a lot of project time.

One side note about my Lean Burn Monitor that I've been working on: I think I'm going to scratch the project as I'm finding out that in order to recoup my time in developing/manufacturing a quality circuit board for it, the price would be driven over $20. My intent with that project was to never go above that cost as the only output of the device is just a simple LED. Maybe I'll just build the Lean Burn Monitor on a per customer basis.

I am totally going to read up more and see about either buying or building one of these once the display issue is settled more. My vote stands for a backlit LCD of a common size.

dcb · 04-25-2008, 08:16 PM

Quote:

Originally Posted by TomO

I am totally going to read up more and see about either buying or building one of these once the display issue is settled more. My vote stands for a backlit LCD of a common size.

I think the hardware is pretty settled for guino 1.0. A number of people have procured this 16x2 from the same place that had the freeduinos:
http://www.nkcelectronics.com/16x2-l...backli162.html

Reasoning was it was simpler to order it because it was from the same source as the board. And it was less than $10. At least two people have gotten this model working with their 'duino, so the instructions must kinda work. The display itself is nice and bright and easy to read from a distance even. The only issue left with it is the software, which would be true for any low cost parallel lcd we order.

So unless anyone has any objections, lets go with http://www.nkcelectronics.com/16x2-l...backli162.html as the official LCD of the openguage mpguino 1.0 project.

MetroMPG · 04-25-2008, 08:50 PM

I'm going to assign the OpenGauge / MPGuino threads to their own subforum within "Instrumentation". The project deserves the raised profile of its own home, plus it'll make it easier to keep all the threads together.

I still haven't connected my LCD to my duino yet. Fixing a surface mount LCD ribbon slot on a busted ScanGauge is my current soldering job. (Solder with a magnifying glass).

TomO - got any advice for soldering tiny repair wires onto pads that are about .5 mm wide and .25 mm apart? Yikes! Actually I've done most of them already, but I probably did it the hard way....

MetroMPG · 04-25-2008, 11:38 PM

The guino threads now reside in a dedicated sub forum.

paulb · 05-01-2008, 07:50 PM

I'm really interested in this. I make a line of open-source Arduino clones and can do some board design and programming.

The scan gauge just does it with a 2x16 LCD - they're in stock on my site with a driver chip.

Paul Badger
moderndevice.com - website

jmonroe · 05-02-2008, 01:03 PM

I just found this after working on my own arduino system for about 2 months now. I have a 2x16 LCD with a serial adapter and an arduino connected to a ELM323. The arduino requests data from the ELM, gets the results, does the math and then sends updates the LCD. I will hopefully take some pictures and get it online.

It is not working yet. I can send and recieve from the ELM and Display to the LCD. However, when I send commands to the ELM, I get the Bus INIT message every time and no real data is sent back. I hope to make some progress this weekend.

paulb · 05-02-2008, 05:18 PM

What does the elm chip buy you? Is parsing out the OBD2 data really knarly? And is every car different? It would seem to be that in the service of making this thing as cheap as possible it would be a good idea to keep parts count down. On the other hand it might make sense to get the thing working first.

Any pointers to the OBD2 protocolls - seems like I saw some on the elm site.

Anyone taken apart their scan guage to see what hardware they're using.

FYI - there are two articles in Circuit Cellar on building fuel economy gauge - so maybe a lot of the hard work is done - One uses an Atmel chip although not a 168.

I'll be glad to provide free hardware, boards and LCD's for people working on this project. Just to keep people honest you have to buy the initial hardware and I'll provide a second set or reimburse you when I see some evidence of contributions.

This is a project that has the potential to be a great boon to society (in contrast to Bush's wimpy CAFE standard rise) so I'd really like to see it get off the ground.

Guess I'll order a couple of elm chips and see how they work.

Paul Badger

jmonroe · 05-02-2008, 05:46 PM

Yes, there are several different OBD protocols. Mine is ISO9141 so, I just have an ELM 323. If you were building something that worked with all OBDII cars, I would use the ELM 327 even though that is an expensive chip and the supporting components bring the whole thing to around 50 bucks + freeduino and LCD costs.

I would bet that it is possible to do this without the ELM, I wanted to get something working. I am not that experienced when it comes to this sort of thing.

If there are others working on it, I would ultimately like to be able to cut the ELM out and run it purely with the Arduino or use another cheaper chip to replace the ELM (say a dual processor arduino)

You can count me in for further development, as long as it doesn't require (many) more parts. I could barely afford what I did already

larrydag · 05-02-2008, 06:45 PM

I agree with paulb. I'm not sure what the ELM chip buys you. The idea of the Opengauge/MPGuino is to provide a minimal hardware interface into a car that is electronically fuel injected. The only inputs the MPGuino would need is VSS and Injector pulses. These typically can be received from pinouts on the ECU (or similar control unit). An arduino/freeguino should be able to receive these natively from a simple circuit interface.

If you really want to use the ELM maybe you could develop a handheld or laptop interface. That could be an interesting project. I'm not sure you would even need the arduino at all in that case.

jimboradley · 05-02-2008, 07:23 PM

Hi guys. I recently found this thread and am super excited about it. In college I majored in computer engineering, so I have software experience as well as hardware experience. I'd love to help out on this project.

One idea/question, and forgive me if this has been addressed already.
I liked the idea of doing this on a palm, because it's already got a display and a touch-screen interface, but someone said that one problem with that was that you'd need a *duino AND a palm to do it and that's overkill. Does anyone know if it's possible to hack a USB cable and do it all in software on the palm (not sure if all palms have usb?), cutting out the *duino, similar to the guy who did it through his soundcard?

Anyway, it's just a thought. I really would like to get in on this project, so let me know where I can help.