The interface board was built by my dad in November 2011. He made it so I could connect my Apple //e to my Snap Circuits, but, it can be used to connect to anything that uses low voltage, like k'nex motors, sprinkler valves, Estes rocket engine igniters, etc. Below are the pin-outs for the Apple //e game port; and, how PB0 .. PB2 (push-button inputs 0, 1, 2) & AN0 .. AN3 (annunciator outputs 0, 1, 2, 3) map through the external interface keeping the Apple //e electrically isolated by using micro-relays and phototransistor ICs.
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Pinouts for Apple //e Game Port
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16-pin DIP (Dual Inline Pin) socket
+-v------+
+5V | 1 16 | Not used
PB0 | 2 15 | AN0
PB1 | 3 14 | AN1
PB2 | 4 13 | AN2
Strobe | 5 12 | AN3
GC0 | 6 11 | GC3
GC2 | 7 10 | GC1
Gnd | 8 9 | Not used
+--------+
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Pinouts for Interface Connector
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20-pin DIP (Dual Inline Pin) plug
--v--------
Black -+ nc nc +- White
off Grey -+ +SW3- +- Purple 0v
off Blue -+ +SW2- +-
Green 0v
off Yellow-+ +SW1- +-
Orange 0v
|---------|
o\ Red -+ncc | ncc+- Brown /o
o Black -+ AN3|AN2 +- White o
o
Grey -+noc | noc+- Purple o
|---------|
o\ Blue -+ncc | ncc+- Green /o
o Yellow-+ AN1|AN0 +- Orange o
o
Red -+noc | noc+- Brown o
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