Scangauge Xgauge -make a new gauge via math operations on existing gauges?

atroader · 03-19-2008, 06:03 PM

So many of us have now used the Scangauge successfully; however a point of good feedback while driving is a single metric to indicate how efficient we are as drivers. The MPG gauge gives us this metric for the most part.

But, during acceleration, its nice to know how effectively we're using fuel. For this, I'd like to make a new Xgauge for acceleration effectiveness. Essentially, its the derivative of mph divided by fuel burn rate. This works out in metric to m/(s*kg_fuel). (You could consider the inverse just like mpg w/ l/km if you like). The higher this metric (or lower the inverse), the less fuel is used per unit of velocity added.

To make such a metric, I need to do a little math in the Scangauge. I need to make a pseudo derivative w/ 2 mph readings and the sample rate, and then average the fuel flow rate for the two samples also to divide by. Are there any experimenters out there w/ the Scangauge that have knowledge that could get me started?

Admittedly, I'm adding this gauge for my other car, not my prius, to see how this changes with gear ratio and engine load. But, I feel it would be an interesting trend to follow in the prius nonetheless.

Bob64 · 03-19-2008, 06:29 PM

The Xgauge feature does not support multiple "variables".

The xgauge basically spits out a variable X, which you can do the following:

X * ? / ? +- ?

? = a constant, which can be different in each spot.

But you must complete them in the order listed above. Multiply by a constant, divide by a constant, and finally add or subtract a constant.

As far as I know, you can't substitute the constants with outputs of other xgauges.

atroader · 03-20-2008, 08:33 AM

The single variable limit is what I had feared. So it looks like unless I were to get myself into chip programming mode and essentially 'hard-code' a new gauge in scangauge, this will not be possible.

This isnt really possible w/o having the original assembly or C from linear logic- since what's on the chip already will be compiled. I do remember hearing talk about a USB link between the scangauge and a computer for data-logging etc. Does anyone know if that will be available in future releases? It would at least provide the first step w/ hardware for easy reprogramming for new CAN data or my application, provided one has the original code to modify.

Thanks for the reply.

SpartanScott · 03-20-2008, 01:10 PM

Quote:

Originally Posted by atroader

I do remember hearing talk about a USB link between the scangauge and a computer for data-logging etc. Does anyone know if that will be available in future releases? Thanks for the reply.

When I talked to Linear Logic two weeks ago they said there will be no new redesign or releases in 2008 (except for posting new X-Gauge info). The only thing he said they were researching is the interest for a add on screen that would allow more gauges to be shown. It would be a cheaper alternative to buying a second scan gauge to show 4 more lines. I did not ask about their data-logging plans at the time so will leave that to the next caller.

03-19-2008, 06:03 PM	#1
atroader Engineer Join Date: Apr 2007 Location: Atlanta, GA Posts: 10 My Car: 2007 Prius Package: #1 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Scangauge Xgauge -make a new gauge via math operations on existing gauges? So many of us have now used the Scangauge successfully; however a point of good feedback while driving is a single metric to indicate how efficient we are as drivers. The MPG gauge gives us this metric for the most part. But, during acceleration, its nice to know how effectively we're using fuel. For this, I'd like to make a new Xgauge for acceleration effectiveness. Essentially, its the derivative of mph divided by fuel burn rate. This works out in metric to m/(s*kg_fuel). (You could consider the inverse just like mpg w/ l/km if you like). The higher this metric (or lower the inverse), the less fuel is used per unit of velocity added. To make such a metric, I need to do a little math in the Scangauge. I need to make a pseudo derivative w/ 2 mph readings and the sample rate, and then average the fuel flow rate for the two samples also to divide by. Are there any experimenters out there w/ the Scangauge that have knowledge that could get me started? Admittedly, I'm adding this gauge for my other car, not my prius, to see how this changes with gear ratio and engine load. But, I feel it would be an interesting trend to follow in the prius nonetheless.

03-19-2008, 06:29 PM	#2
Bob64 Sapphire of the Blue Sky Join Date: Apr 2007 Location: Virginia Posts: 764 My Car: 2007 Prius Package: #2 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Re: Scangauge Xgauge -make a new gauge via math operations on existing gauges? The Xgauge feature does not support multiple "variables". The xgauge basically spits out a variable X, which you can do the following: X * ? / ? +- ? ? = a constant, which can be different in each spot. But you must complete them in the order listed above. Multiply by a constant, divide by a constant, and finally add or subtract a constant. As far as I know, you can't substitute the constants with outputs of other xgauges.

03-20-2008, 08:33 AM	#3
atroader Engineer Join Date: Apr 2007 Location: Atlanta, GA Posts: 10 My Car: 2007 Prius Package: #1 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Re: Scangauge Xgauge -make a new gauge via math operations on existing gauges? The single variable limit is what I had feared. So it looks like unless I were to get myself into chip programming mode and essentially 'hard-code' a new gauge in scangauge, this will not be possible. This isnt really possible w/o having the original assembly or C from linear logic- since what's on the chip already will be compiled. I do remember hearing talk about a USB link between the scangauge and a computer for data-logging etc. Does anyone know if that will be available in future releases? It would at least provide the first step w/ hardware for easy reprogramming for new CAN data or my application, provided one has the original code to modify. Thanks for the reply.