Any interest in developing an open source fuel economy gauge/computer?

[MetroMPG]

The Arduino has serial output (and input - that's how it's programmed), not sure about the other platforms mentioned so far.

[MetroMPG]

Originally Posted by trebuchet03

That's just me, as someone with limited experience with microcontrollers - which is very likely the case for someone that is going to replicate any efforts.

Originally Posted by LostCause

Look at the simplicity of the design compared to the arduino. No pre-etched board and just a bunch of components that can be bought at once from Digikey, Mouser, etc.

I'm with Trebuchet, because of my experience with this stuff ( = nil).

The thing that appeals to me about the Arduino is that it's ready to go, and I understand the programming process - plug it into a PC serial port and install the code.

I wouldn't know where to begin if I also had to select components & make the platform.

How is an atmega or other IC programmed?

[dcb]

I think it has to have some kind of display, and an instantaneous and at least one resetable trip readout, to be a really useful "learn how to drive again" tool.

So at a minimum it:
1. has instant MPG displayed at all times.
2. has trip MPG displayed at all times.
3. is cheap on parts.
4. is adjustable to different vehicles.

Other computable items from injector pulse and speed sensor:
RPM
MPH
Gallons
Distance
Acceleration
Decceleration
Hours

[dremd]

I can't help much, other than my moral support, and pledge to buy one for my supra once it gets going.

Once feature that my bike has, that my SGII lacks is Cadance, might be cool for MPG computer . . .. . . Just an Idea.

[LostCause]

Originally Posted by MetroMPG

I'm with Trebuchet, because of my experience with this stuff ( = nil).

The thing that appeals to me about the Arduino is that it's ready to go, and I understand the programming process - plug it into a PC serial port and install the code.

I wouldn't know where to begin if I also had to select components & make the platform.

How is an atmega or other IC programmed?

It seems that the arduino uses an atmega168 microcontroller w/ a bootloader, so it is programmed directly via serial/usb. I think other IC's (PIC, BASIC Stamp, etc.) require a board to interface with a computer via serial. Really old stuff (EPROM) requires data to be erased by UV and then loaded. Thank goodness it's not 1984...

Since I also have no experience I won't advocate the tough path anymore. It just seemed like the logical path if the experience can be found in this board. Essentially, the end product would be MegaSquirt-esque: purchase components, solder, download code, install, done...

If the arduino path is taken, another option is the freeduino: completely open source + USB. ~$24



Info for getting an LCD up and running. Apparently, to have buttons, input pins available, and run an LCD it needs to operate in 4-bit mode. Here's what I've found so far.

Reasoning
LCD interface in 8-bit
LCD interface in 4-bit
Source of LCD's (w/ or w/o backlighting) ~$15-20

This is kind of dumb, but what about an "analog" fuel economy gauge?

- LostCause

[MetroMPG]

Good link. Anything with "free" in the name must be good!

I just ordered one.

[trebuchet03]

Originally Posted by dremd

Once feature that my bike has, that my SGII lacks is Cadance, might be cool for MPG computer . . .. . . Just an Idea.

Isn't RPM the same thing?

[LostCause]

Originally Posted by trebuchet03

I know you can buy, from SAE, the book on the OBDII protocols and how to interface - probably something necessary if you want to plug into the diagnostics port and not tap a bunch of misc. wires.

1.
2. Bus positive Line of SAE-J1850
3.
4. Chassis ground
5. Signal ground
6. CAN high (ISO 15765-4 and SAE-J2234)
7. K line of ISO 9141-2 and ISO 14230-4
8.
9.
10. Bus negative Line of SAE-J1850
11.
12.
13.
14. CAN low (ISO 15765-4 and SAE-J2234)
15. L line of ISO 9141-2 and ISO 14230-4
16. Battery voltage

The assignment of unspecified pins is left to the vehicle manufacturer's discretion.

PID's for requesting information (i.e. water temp, TP, vehicle speed, etc.)

Now, how to use all that data...

- LostCause

[LostCause]

Originally Posted by MetroMPG

Good link. Anything with "free" in the name must be good!

I just ordered one.

Man that's fast... I think I might too, I like how this is rolling along quite quickly.

The internet is a cool place, like a mega-library.

Adding buttons
Tutorial List

- LostCause

[MetroMPG]

Originally Posted by LostCause

I like how this is rolling along quite quickly.

Oh, don't mistake my buying one for committing to the project!

That said, if several of us were to get the similar platforms and start investigating further, I could see how it could snowball into actual progress.

Re-reading the thread, I can see why the *duino may not be the perfect platform for this project for a couple of reasons. But I've been intrigued with them for a while, so I thought, might as well get one.