Hi all,

i'm my 16F88 temp monitor project i have a LM35 sensor with no vref.
The input voltage for the workbench was always 5v and everything is working perfectly.

After moving for the pcb i have found an issue that puzzled me.

For the PCB aplication i have it connected ( via 7805 ) to a 4.8V NiCd pack. This pack when fully loaded is 5.3V and after some use it drops to +-4.5V.

This is causing some bad temperature readings when the pack drops bellow 5v.

The code i used for temperature is like this :

temp= (in */5000)>>2

I have no vref because i can live with the 0.5ºC stepping ( 10Bit resolution ) and this code allows me to have an output like XXX,X.

My question is:

Is there a better code to be flexible with the input voltage and still have accurate readings ?

Thanks