Some of that info is already collected and used for oil change interval calculations on many cars. Unfortunately, the raw data isn't presented to the driver in most cases, unless you hack into the car's computer.
Isn't that kinda like what the OLM is already doing? I get about 3400 miles every 100 engine hours and have gone up to 150 hours before changing my oil. I know this is not an OLM I just watch the miles vs the hours on the oil since changing and use my best guess when its due. The computer has all kinds of goodie info in it I would like to be able to see!
Also, if your OBC records average speed, you can easily figure out the hours by taking the miles driven since last oil change and dividing it by the average speed (assuming you reset it at the time of last oil change).
So, if I drove 10,000 miles and my average speed was 40 mph during that time, it means I've ran the engine for 250 hours. It may not be exact, but it should be close enough.
I've heard of "DIY" methods being done.....don't see WHY....? lol. I can't see hours/minutes being that big of a deal, unless you do a serious amount of "idling" (drive thrus, drive in theaters? lol).
When my car is on, it's driving