TEMP display in F from LM335 sensor

Forum 2005-2010 (read only) Hardware Interfacing
1

I have a MEGA with a 16x2 LCD, and I want to display the inside and outside temps of a car. Im having trouble converting the readings from the port to actual F readings. I have the ADC values as well for referenced temps off a thermometer I have. The numbers seem to be backwards though. Any help would be great!!!

ADC Readings:

39F = 631
44F = 626
80F = 606
128F = 571

if I convert them to remainders,
TEMP = 1023- ACD
39F = 392
44F = 397
80F = 417
128F = 452

Looks like there is no correlation for either value, Im at a loss right now.

2

Richard, looks like you've come to the rescue again! I didnt graph it out I was simply dividing the ADC reading by the temp and that wasnt giving me anything. Ill look into the map function and see if I can get it up and running. Thanks!!

3

Plugged in the MAP function, worked like a charm!!! Accurate almost to the degree. I love Arduino.