Calibration performed for NTC probe w/ Phidgets
So, I calibrated a NTC probe:
-- AVX Type NI24 --
with a 463 ohm resistor, in a voltage divider arrangement.
From 35 Degrees F to 190 Degrees F.
I can say with 95% confidence that the following curve fit equation is accurate to +/- 1 degree from 35 degrees to 190. In some cases it is better than .3 degrees F accurate.
N = -1.4618 * N ^ 6 + 21.062 * N ^ 5 - 127.38 * N ^ 4 + 409.96 * N ^ 3 - 731.9 * N ^ 2 + 626.52 * N + 10.658
Where N is the phidgets sensor raw value.
I've incorporated this logic into the latest revision of the RR source code.
PM me if you need some of the thermisters, they're more accurate and cheaper than the phidgets variety.
Compare to Phidgets, which has an accuracy of +/- 4 degrees F, and are mounted on a board....these thermisters can be epoxied to anything.