[Diy_efi] DIY_WB and stand alone ems

[Brian Dessent]

Jurgen Hartwig wrote:

> The only way I see it is possible (at least from my limited experience) is
> to use a microprocessor with A/D convertor (from WBO2) and then D/A
> convertor (to Autronic).  I think that is what will work, but I haven't the
> foggiest idea how to do it.  Also, I noticed that the voltages out of the
> WBO2 were fluctuating rapidly.  It could be because my sensor was in the
> tailpipe, or maybe it was the leaking exhaust flanges.  If the voltage is
> not stable, I imagine you would need some form of filtering???
> 
> Anybody else have some insight?

It's always been a back-burner goal of mine one of these days to make a
generic transfer function "black box" project.  You'd have an a/d, d/a,
and sitting in between a uP with a lookup table, possibly with
interpolation.  I'd use discrete data converters since you can get
impressive resolution and speed and still use a dirt cheap
microcontroller.

Add in some addressable digital pots for the analog front/back ends and
you get programmable offset and gain so that you ensure that you use the
full range of your converters.  Also some very basic digital filtering
(window-average) is possible.  Now you have a simple device that can
reliably translate any nonlinear i/o curve, such as:

linearizing diywb's output
emulating a NB o2 sensor from the WB's output, so that you could run the
WB in the stock location
VAF->MAF conversion
selective enrichment/enleanment by adjusting sensor output curves.

Brian

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