rg20+@andrew.cmu.edu (Rick Francis Golembiewski) (12/01/88)
Humm.. you may have some trouble making the amiga into an oscilliscope using the game port because the game port measures RESISTANCE, while a 'scope measures voltage. I tried to make something similar using the Apple II (hey the amiga wasn't around at the time...) and its analog game port, unfortunately I ran into the above problem, and I also found out that LOGARITHMIC scales are a pain (I assume that the amiga uses a similar design, measuring the resistance of a logarithmic pot and generating a hex value...). Even when using a variable resistor (ie thermistor) the calculations to calibrate the values into something meaningful (in this case a temperature) where pretty nasty and also required you to have some callibration data (you needed 2 states one near minimum resistance and one near maximum...). In order to make an oscillascope you would need something that can vary its resistance from 0-1M ohm. over a relatively small voltage (ie maybe 5 volts, so that you could read most common circuits, although 1 Volt would be nice since you could get more scales just by adding resisters...), I could not find such a device (perhapse a photo resistor/LED combination, but I couldn't find one with that kind of resistance, maybe a bunch in series if you amplified the signal going to the LED...). Needless to say this is not something that you could really whip up in a few minutes... and I'm not sure how stable it would be one you actually got it working (remember that temperature cna have a big affect on the resistance of a semi-conductor). In any case, I believe that there is a comercial product that turns your amiga into an oscillascope, but I'm not really sure if it ever came out/ is still in production... +----------------------------------------------------------------------------+ | Disclaimer: Me? Post That, impossible I never post anything... | | TypetoYouLater(Everyone); --> "functional Good bye".... | | Rick Golembiewski [ Pronunciation is half the Battle, spelling the other] | +----------------------------------------------------------------------------+