# Automotive Sensor Resistive vs Temp equation

I have found a few threads on the GM 12146312 sensor and the formulas used to get a temp from it but the project im working on, I'd like to use a bit smaller sensor like this one

http://aemelectronics.com/files/instructions/30-2012%20Water%20Temp%20Sensor%20Kit.pdf

It lists all the data for the sensor, it does seem to be different than the GM sensor than many use.

My project is going to be a Transmission oil temp sensor, and the small space that the fittings go, the smaller temp sensor seems to fit best.

Thanks,
Chris

Do you have a question?

Im sorry for not being clear.

I'd like to know how to figure out an equation to use with this (or other sensors I have proper data for).

Did you see these tables?:

Just map the voltage to a temperature value. Simple.

I have found a Steinhart-Hart Calculator (I think I have seen others use the Steinhart-Hart calculations for other resistive based sensors)

https://www.thermistor.com/calculators

I just dont know what to do with the data that it spits out or even if Im going in the right direction.

As far as mapping, this would not get me accurate measurements between mapped points right? I guess I could figure out a way to interpolate between the values.

consonar:
I have found a Steinhart-Hart Calculator (I think I have seen others use the Steinhart-Hart calculations for other resistive based sensors)

No, forget that.

consonar:
I just dont know what to do with the data that it spits out or even if Im going in the right direction.

You'll be heading in the right direction if you map the values based on the tables given.

consonar:
As far as mapping, this would not get me accurate measurements between mapped points right?

Ridiculous. Of course it will. (that is, if you have a pull-up of exactly 2.2Kohms)

consonar:
I guess I could figure out a way to interpolate between the values.

Try this.

Thank you for pointing me in the right direction!

If you prefer an equation Ametherm has a good explanation of how to calculate thermistor parameters and how to use them.

I don't believe mapping will work, it's linear and thermistor resistance vs temperature is not.

Mapping has been used for decades in automotive and industrial systems. Even now with high clock speeds, multi-cores and FPU's in automotive microcontrollers we rarely use equations to convert ADC readings to temperature. Using lookup tables you can trade memory for accuracy. If you need really high accuracy, use many more points. You can put more points in the most important range and fewer in less critical areas. Linear interpolation is a pretty good approximation across short sections of the curve.