PLEASE CAN ANYONE HELP ME ON HOW TO DESIGN A COMPUTER BASED VOLTMETER TO READ IN AC AND DC VOLTAGES FROM ITS SERIES OR PARALLEL PORTS AND DISPLAY THE READINGS ON THE MONITOR USING PASCAL LANGUAGE
Well my idea is a bit different. I would use PC sound card for it. If 555 timer is used as voltage controlled oscillator then the pulse width of the output waveform can be detected using some programming. I haven't implemented it yet but may be a precise solution.
Another idea is to use Microsoft text to speech engine so that the sofware speaks aloud the reading once it gets steady. In this way, it would be convenient to take readings without looking into the monitor.