Actually, I was thinking of a tone that peaks when you are accelerating most efficiently. If you give the computer throttle control it might be able to find the most efficient accelerator setting for you (for a given gear).

skewbe -

Ha ha! I was thinking that this would be a perfect 2600 article, and here you are talking in terms of "tones" for your solution.

Most excellent work!!!!! I think you should publish this in https://www.makezine.com

CarloSW2

I got a request to provide a binary, so, just this once. If your signal looks like mine (vss cranked on the left channel, injector upside down and about the same height), it might work out of the box.

you will have to save this Mpg.zip file somewhere then run (trust me?!?)
java -jar Mpg.zip

from a command prompt in that directory, or put a shortcut together, whatever. Google is your friend. If you see error messages, start there, or give yoshi his $170 bucks :)

the power of open source, now you just need a odb/odbII to usb2 for newbies and downloadable exe and your set!

Not obd, not for newbies, not exe. It's for folks who can figure out how to compile a "hello world" program in a given language, who can put a simple circuit together and hook it up to the vss and an injector, and can make sense out of what they are seeing.

I'm not even going to try to compete in the support department with paid for products, this is Do It Yourself land (that means you too) :)

Hypermiling User Interface idea:

I think one of the useful things for hypermiling not done by SG2 that this software could do is compute MPG by speeds.

Here's the idea:

Create buckets of speeds, say:
0MPH, 1~5MPH, 5~40MPH, 40~65MPH, 65~100MPH.

For each bucket, compute
- GPH
- average time spent in that bucket
- distance travelled in that bucket
- MPG (when applicable)

Also compute overall MPG.

Now say you're driving in the city, with some highway.

At first you drive normally, and check your buckets, see time spent in each and what part of your driving contributes to your overall MPG.

Now start using hypermiling techniques that apply to specific buckets.

For example, if you see you spend most time on stop lights (the bucket 0MPH will tell you how much gas it costs you), then you know you must turn of your engine at lights to improve MPG.

If the profile shows it costs little gas though it may seem like a long time while you drive, you know you don't need to risk damaging your starter and look for another solution.

Say you spend your gas in the 5~40MPH buchet. Then you can try to focus on gliding.

If it's at highway speeds, then you can try to use drafting instead, and maybe gliding.

The time spent per bucket can also tell you something as you try different techniques, like gliding causes you to hit more red lights, so you need to be more aggressive.

OK a few other things:

- Do you have PICs of the setup, where you wire-in onto your car for collecting Vss and injector signals?

- For OBD-1, you can buy a scan cable, and you could use it to connect a serial cable, with an open source software AND collect the same info I suspect.

- For OBD-2, the scan cable has to hook up to a device ($) that processes and converts the info into data that can be passed to a USB/serial cable.

re buckets: Sure, you can do that, have a blast :) You will need to program a tiny bit. If you add trips for each bucket and at the bottom of processChunk, look at instant.mph() and call update on the appropriate trip(bucket), that will get you close.

re: pic, don't have one, mine was just a couple sewing pins soldered to the resistors and stuck into the appropriate wires. I do not have a permanent installation yet though am considering it. There is a number of folks that already have computers running linux or windows in their cars, for whatever reason.

re: obd, yah someone posted a whole bunch of obd stuff earlier in this thread. That road has been pretty well travelled, and I'm not going down it myself. This approach is universal to electronic fuel injection vehicles and operating systems, and that is worth something.

Agreed :)

I was just currious where you tapped the info and routed the wires.

It helps to have photos to actually commit to do it yourself. There is a sense of concretization, and understanding that the solution is complete :)

Looking at your "diode clamp" again, I have this to say:

I think:
- VSS trips the diodes (sharp horizontal cutoff)
- Injectors voltage is too low and does not trigger the clamp (no cutoff).

It seems to be a 0.4V swing, comparing to VSS cutoffs.

- R is only to limit current if the diode passes current (aka voltage from 0.6V to 13V). At 10KOhm, that is max 1.3mA draw. I dunno if that is noticed by the car's Vss/injector circuits. Likely not?