MPGuino and Coolant temp sensor signal

[meelis11]

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

[dcb]

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.

[meelis11]

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?

[dcb]

That's the idea. Of course no guarantees, but atmegas are only a couple bucks.

[NachtRitter]

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.

[dcb]

I mapped out a map sensor connected to an atmega over here, fyi
Reading a MAP sensor

might be more useful than temp, or offer some thoughts on temp anyway.

[NachtRitter]

Interesting, and thank you