Quote:
Originally Posted by stevesnj
i want to do a direct connect to the sending units, still researching how to interface them.
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I just put a link to how I got things wired in and the software configured. But I actually think this would be much easier to do than interfacing with senders over ELM327...
All of the ones people care about are 5V reference voltages with separate supply voltages, so hooking them up to the ADC pins on a Raspberry Pi or Arduino should be no big deal. All you'd need access to is the sender data sheet for calibration purposes. Personally I'd just buy a few off the shelf examples to experiment on before I started splicing into my car.
When I looked into the O2 sensor for instance, it has a ~2-4.4V band, but it's effectively a wideband sensor. You can just tap into the sense wire and hook it up to the IoT device of your choice. The Raspberry Pi uses 3.3V logic levels, so it might need a buffer, but there are plenty of those floating around.
Incidentally, which is probably why almost noone uses ELM327 for sender interfacing. I found it to be pretty obtuse to write software for compared to how just hooking things up to GPIOs would be.
The ECUtek logging software I use appears to just read the whole ECU memory over CAN and decode the individual registers from it as one multiframe request, but I found my solution to be almost as responsive as there's, so I don't think there's much reason for me to look into it. I doubt they'd share with anyone how they're doing that, anyway.