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Old 09-15-2010, 03:21 AM   #1 (permalink)
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MPGuino and Coolant temp sensor signal

Hi,
I would like to see coolant temperature on MPGuino but I dont know how to connect it to MPGuino.
Has anybody done it? Schematic/sketch would be nice

I know that coolant temperature sensor varies resistance and ecu sends 5V into it.

I measured it some time ago, some example measures:
* outside temp 18C, engine not started = 2960 ohms.
* warm engine (ca. 90C) = 170 ohms
* 4 hours later 1325 ohms

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Old 09-15-2010, 07:18 AM   #2 (permalink)
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Can you measure the voltage on the sensor? It is probably part of a voltage divider circuit, and if it is putting out in the range of 0-5 volts then it is suitable to be read by an atmega without extra circuitry.

The next problem of course is adding some code to read it and display it.
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Old 09-15-2010, 07:58 AM   #3 (permalink)
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I think it is powered with 5V but I better measure it.
So if it is 0-5V then I can just attach wire to sensor wire and other end to ATmega pin?
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Old 09-15-2010, 08:09 AM   #4 (permalink)
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That's the idea. Of course no guarantees, but atmegas are only a couple bucks.
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Old 09-15-2010, 01:06 PM   #5 (permalink)
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Similar setup in my VX; Interested in doing the same thing. I can do a direct connect, but anything outside of that is a mystifying to me.
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Old 09-15-2010, 01:11 PM   #6 (permalink)
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I mapped out a map sensor connected to an atmega over here, fyi
http://ecomodder.com/forum/showthrea...nsor-5208.html

might be more useful than temp, or offer some thoughts on temp anyway.
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Old 09-15-2010, 01:20 PM   #7 (permalink)
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Interesting, and thank you

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