i2c based fly by wire throttle prototype

video: http://www.youtube.com/watch?v=tciLgdMQsOE

code: http://jason.pepas.com/wiki/index.php?title=I2CFlyByWireThrottlePrototype

That’s a nice demo. It seems a little scary, though. What would happen if, for instance, one of the I2C wires broke while the engine was at full throttle?

For safety, a good rule of thumb is that no single point of failure should result in a hazardous condition. Assuring this rule is met may require analyzing all possible failure modes of every system component.

BRAVE!

add in a code for if the i2c fails cut all engine power and fuel XD

--What would happen if, for instance, one of the I2C wires broke while the engine was at full throttle?--

It's called a Toyota Avalon.

thanks for the suggestions guys. I should have mentioned in the video that I'm looking into a couple of ways to do a fail-safe (both involving things which would spring shut should they lose power).

--What would happen if, for instance, one of the I2C wires broke while the engine was at full throttle?--

It's called a Toyota Avalon.

From what I read in the news, Toyota's massive recall for "Sudden Unexpected Acceleration" may have roots in engine control software. I wonder what scheme Toyota uses for engine control? We hear of several theories: floor mats, sticky pedals, stiction due to wear or humidity, an unknown difference in the way an Indiana factory and a Japanese factory build (supposedly identical) pedals. It sounds more like frenzied speculation than identification of [u]the[/u] cause. There could be multiple causes, but it seems unlikely that Toyota would so monopolize them.

It is virtually impossible to guarantee that software is defect free. It is always subject to failure of the chip on which it executes. When lives may be at stake, multiple, independent failsafe strategies should be considered.

What's "funny" about the problem is that none of those people who have had this problem (especially the ones who died in a resulting accident) ever thought to turn the ignition off, or shift into neutral...

Sure, you might have to manhandle the steering wheel and pump your brakes (though I have seen "fly-by-wire" braking systems, too - sheesh); or your engine might seize up from red-lining - but that is better than being injured or dying.

With that said, I've been in the same situation before, and I have to say both of those things weren't the first thoughts running thru my head (it didn't help that I wasn't more than a 500 feet away from an intersection where I had the red!); I ended up getting the car mat out from where it had stuck the pedal down (1994 Ford Ranger - aftermarket crappy floor mats) and got slowed down, but it was an interesting ride!

One of the best things you can do in any vehicle is to get heavy rubber floor mats, or get rid of them entirely.

Ultimately, the best and most-likely-to-always-work failsafe lies right between your ears.

:)