Quote:
Originally Posted by jyanof
i'm confused - why not just use the 3rd order curve fit equation? It'll take some time for the processor to crunch through it, but it's not like you need to display the temp at a high refresh rate...
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Really it's just down to processor time vs. accuracy. Unlike a desktop pc, most micro-controllers are limited in their math functions, this one is signed 16 bit integer maths. The look-up table approach will sacrifice some accuracy for speed and also ease of coding. I did have a play with the equation y = 0.0000007 * x^3 - 0.00081698 * x^2 + 0.40709038 * x - 41.63772692 in openoffice and got a graph that looked just like yours!
so I can use that to create a look-up table for temperature conversion. One question, what is the equation R^2 = 0.99705769 for?