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Old 02-22-2017, 01:14 PM   #84 (permalink)
t vago
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Join Date: Oct 2010
Location: Cedar Rapids, IA
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Originally Posted by skybolt View Post
I'm impressed by the sheer amount of optimization you did in the 02/08 release. That kind of optimization isn't cheap.
Thank you! That's high praise indeed.

Originally Posted by skybolt View Post
The 02/16 build is working well in the car, including the drag stats. Right now I'm chasing something in the odometer -- I think the in-car odometer rounds up to the nearest tenth, with a resolution of a hundredth. I'll know more once the trip mileage hits 1000 and I show the exact number of ticks (by setting ticks-per-mile to 100). I believe 1 mile was 8196, 10 miles was 8199, and I did a ghetto calculation at 160.1 miles that matched when I set the ticks to 8201. Rounding is the only reason I can think of why the odometer wouldn't match the Arduino exactly I did notice it when the Arduino reported x.996 as the mileage when the odometer changed, but by going to 1000 miles I can measure quite precisely, and I can expose any rounding done by the odometer by shifting all the digits to the left.

My speed sensor should trigger a tick every 5.7 inches, and the duino has a resolution of 5.28 feet. I've noticed the speed sensor won't trigger at under about 0.5 mph, but even in that case the odometer and arduino should match since both are simply counting speed ticks.
I am thinking that the rationality checks I built into the VSS input capture code, way back when, might be interfering with the MPGuino's ability to measure small distances. I never figured that MPGuino would be used to do this sort of fine measurement.

Come to think of it, I'm not even sure that the VSS needs rationality checks. It's nowhere near as complicated a signal as the fuel injector signal.
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