One dark and stormy night, I, Dirk Trippster, Automotive detective, got a call from an old friend:

"Oh, Dirk, you are the only one I can trust.... Can you PLEASE come over and "plug into" my MINI's CAN?"

Oh, yeah, I thought to myself. That's just the job for me.

I had to stop by a friend's house on the way and borrow his sys-tec USB-CANmodul interface, (Yeah, that's spelled correclty) and download some software from systec.com, but I was all prepared when I arrived.

I soldered two wires onto a Philips CAN bus interface chip in her tachometer module, and I took a peek under the covers using an oscilloscope, and I could clearly see the object of my desire. A pair of nicely formed sinusoids. Man, they looked great.

After a little timing, and inversion (I had to use a calculator for this since my slide-rule wasn't lubed up yet), I guessed that the bitrate was around 350 kilobits-per-second, so I tried setting the debugging module at 250 Kbits/second, and I was immediately disappointed.

BUSHEAVY Too many errors on the bus. I struck out at first base.

But if Dirk has learned anything in this rough-and-tumble world of bus-detective, it's never give up (at least right away)

So, on a whim, I tried 500 kbits/second, and I was rewarded with a page full of updating numbers.

Oh, such beautiful numbers. I gave her some gas, and took the revs up to 4500 and I got hit with that warm feeling seeing a small group of the numbers get larger... And larger... and larger as I revved her up.

Over time, I could see a smaller group of numbers expand until the radiator fan came on, and then, as she cooled off, they grew smaller. Hmmm.... Coolant temperature? That's likely.

Over the course of the evening's poking and prodding, she gave up many of her precious secrets. She told me about throttle-position; blinker-indicator; bright-headlights indicator; insturment backlighting status; ignition advance and many others.

She did leave some mystery to make sure I came back for a second tumble though.

Where is her intake airand ambient air temp? What about fuel-quantity? There were some tantalizing glimpses of possibly injector duration or something similar that she just wouldn't let go of quite yet.

I'll sing like a bird after the next meeting (whenever that might be. I need to rest up.)

 

I wrote a C program to capture the messages and went for a drive.

Then I spent a week trying to decode the mesasges, and I have found many things.
Engine RPM, 4 wheel-speed indicators, throttle-pedal position, blinker, highbeam,
parking brake lights, some temperatures (I think) and others I haven't decoded yet.

Here are some fun charts of wheel speed.

First, my entire trip:


And then a left-right-straight turn.


I have no idea what the units are for the wheel speed. I think 1200 units is aronud 35 MPH,
but I need to record some CAN data as well as some notebook data to get the calibration.

 

I'm REALLY disappointed in the accuracy of the blinker-indicator LED in the tach.

Just look at this plot!


The average on-time is 320 milliSeconds, but the standard deviation is 19.7 milliSeconds!!!

That's Awful. MINI should have been able to do a lot better. (Of course I'm just joking here)

(I'm just AMAZED at the things our car's computers talk about behind our backs. Or behind our dashboards I guess)

I'm having a good time eavesdropping.

 

Oh Trippy, you're our technical hero yet again! (is there no emoticon for swooning???) I for one would never have supposed that my car is using its computer to track the blink frequency of the turn signal.

Keep up the good work, and I'm assuming that much like the human genome project, the previous two postings are just the tip of the data iceberg.

 

Ah, Tripster: ever-creative in your attempt to graph all things MINI! YAY!

Clo/Wanda