This page is dedicated to computer hardware
and interfacing external hardware to computers!
This little test/experimenting circuit could be used for many
things.
It compares a unipolar (0..+15V) voltage to the reference voltage. This reference
voltage would be the maximum voltage to detect. If for example a 1.5 volt battery
where connected to the reference pin, then the voltage at the in-pin can be
detected at 0, 0.375, 0.75, 1.125 and 1.5V.
Changing the R1..R4 values can change the resolution of the circuit. For example
with proper selection of R values the circuit could read 1.1, 1.2, 1.3 1.4 volts.
No output would be less than 1.1 volt, typically a 1.5 volt battery would be
exhausted at this level. The 1.4 volt level would be taken as still full charge.
This circuit needs a program to read the printer port. Depending on the LPT
port this circuit connects to, the program must be adjustable to match. This
program could be free ware on the Internet. The language of choice and operating
system are user definable as per preference and availability.
