Re: Apple ii projects for kids?

[mspangler <mspangler@gemsi.com>]

"Only if you need more than 4 bits of output or 3 bits of input. "

If you have a GS, then you have 4 bits of input as the former cassette
input is now on the game port.

On a IIe if you short the leads on the input filter capacitor, you can
use the cassette input port as an input too.

If you are counting pulses, the cassette input seems to work well as
is. I'm not sure how high or low of a frequency the cassette port can
handle, but it worked when I used it on a voltage to frequency
converter. The nice thing about it is that if you mess up all that
dies is a 741 op-amp.

Also on the IIe there is a strobe output ($C040) good for clocking a
flip-flop or something similar. You could probably figure out how to
do the same with the cassette output too. That's just TTL with a
voltage divider. Snip one resistor and you should have TTL voltage
with adequate protection for the IOU (I think that's where it comes
from.)

And you have the paddle inputs too. A CdS light detector on a paddle
input is really simple. Low resolution, but if you just want to detect
day and night, it's easy.

Any more than that and you are looking at a 6821 or 6522 PIA card.
Someday when I've brave and not running my tail off on other projects
(hah, like that will be soon) I'll have to try to build one on an IO
prototyping card. If someone clones the old Applied Engineering IO 32
card and it's software I probably would buy it. But really one 6821
can do a lot.