bigal_scorpio
Active Member
Hi to all,
I am building a PSU with a temperature sensor using a pic 16F872.
The sensor is one salveged from a computer and is just a simple analog bi metallic strip that goes from 1k ohm at 100c to 60k at 0c.
I have used a voltage divider to get the voltage on the pic ADC to be 4.54 at 100c and 0.714 at 0c. If I then read the value from the ADC channel I get 131 at 0c and 454 at 100c.
This is where I am falling down. I can't figure out the formula to convert the pics reading into centigrade.
I thought it would be 454-131 = 323 then divided by 100 = 3.23 per degree c but it seems to be about 3c out (too high) at that.
Does anyone know what I'm doing wrong please
Al
I am building a PSU with a temperature sensor using a pic 16F872.
The sensor is one salveged from a computer and is just a simple analog bi metallic strip that goes from 1k ohm at 100c to 60k at 0c.
I have used a voltage divider to get the voltage on the pic ADC to be 4.54 at 100c and 0.714 at 0c. If I then read the value from the ADC channel I get 131 at 0c and 454 at 100c.
This is where I am falling down. I can't figure out the formula to convert the pics reading into centigrade.
I thought it would be 454-131 = 323 then divided by 100 = 3.23 per degree c but it seems to be about 3c out (too high) at that.
Does anyone know what I'm doing wrong please
Al