volt meter

Archiver

hello all,
i am using the basic stamp II to measure the voltage of a 5 VDC
battery. i have a ACD0831 8-bit A/D convertor, however i'm not shure
how to wire it to read the voltages from 0 - 5.

please help
eric

Archiver

The max voltagean ADC can read is about 4.095 volts. If you want to go
higher your are going to have to manipulate the ADC output to reflect true
battery voltage. This involves putting a voltage divider across the battery
when it is fully charged, set the divider at midpoint, then change the ADC
output, which will probably be about 2.5 volts, toindicate 5.0 volts in your
program. This can done by something like this:

AD1 = manipulated ADC output
result is actual ADC output

Program:

AD1= 400*/result

You will have to play around with the "400". That value will depend on where
you have your divider set. What ever the "result" is, the idea is to
increase it until it equals 5.000, assuming that is what your batter is
charged to.

Sid