data acquistion and logging strategies
Bob Blick email (remove spam text)
I was thinking about someday making a simple device for quick review of a few automobile parameters. I'm not doing any real racing anymore but I do still autocross and the occasional hillclimb, so the races are either under a minute or under three minutes. Actually a lap on most road courses is usually under four minutes. Basically I am not the kind of person who pores over data or race videos or keeps a log book of tire temperatures. I don't even really care about improving my driving that much, but I do care about the car, so after a run I'd like to look at data from the last lap and see how things went. Stuff like air/fuel mixture, manifold pressure, engine RPM, maybe throttle position. I'd have some display I can scroll through. This is not from OBD2 or a diagnostic port, I'd be grabbing data mostly directly.
My car is not running right now, so it's not something I'm likely to do anything about until next year, if ever. Previous datalogging gadgets I have used or built just haven't been any fun so it'd be nice to do something simple that's more of a scrolling display of the last minute.
Obviously one can sample data real fast and store all of it. That uses lots of memory. Sampling or averaging say once per second doesn't use much data, but can miss quick little events. So I was thinking about storing just the peak minimum and peak maximum once a second. Sample fast, store and reset peaks once a second. It only uses twice as much memory as sampling once a second, but it'll catch any weird glitches.
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