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Old 06-20-2013, 04:58 AM   #15 (permalink)
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Originally Posted by t vago View Post
I thought about modifying an OBDuino to take advantage of the fact that it likely would return both a manifold air pressure value and an ambient air pressure value as PIDs, but that was after I had already received this MPGuino. Interesting problem, indeed.

From what I can see, it'll be a simple matter of soldering in another wiring terminal for the two analog channels of this particular MPGuino, then running the wiring to support the two spare MAP sensors I have laying around (one for ambient pressure, and one for manifold vacuum). Since the MPGuino code (excuse me, "sketch") is written in some variant of C, it should really simple to initialize the analog channels, and convert their read-in values into pressure. Only challenge I see is to write a fairly quick square root routine - apparently, the complete math library wasn't loaded into the MPGuino in an effort to save programming space.
You can try to include complete math library - it was not fitting when atmega 168 was used (16KB flash space), if you have atmega 328 chip then you have 32KB of flash - you probaly have enough room for math library.

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t vago (06-20-2013)