DAMNIT!!! still not working. Seems all y1-y6 buttons are on as soon as I plug the circuit in.
I tested some things though:
If i put the meter between pin Vcc and Pin GND of the 74hc154e when the GND of the entire circuit is connected to wire y1-y6 common (see joystick diagram above), I get +2.5v in NEUTRAL. If I ground the entire circuit to the 0v GND input from the USB, I get a +5v.
Done some testing from the beginning of the circuit, it seems there were a few errors on the logic inputs/outputs of the '154.
I tested Low/High's when in each individual gear:
DATASHEET:
https://pdf1.alldatasheet.com/datasheet-pdf/view/27015/TI/CD74HC154E.html
Gear|A0|A1|A2|A3| <--- A0-A3 = CORRECTLY MARKED INPUTS AS ON DATASHEET FOR '154, note its reversed though
1....|.H.|.L.|.H.|.L.|
2....|.L.|.H.|.H.|.L.|
3....|.H.|.L.|.H.|.H.|
4....|.L.|.H.|.H.|.H.|
5....|.H.|.L.|.L.|.H.|
6....|.L.|.H.|.L.|.H.|
Gear 3 was connected to pin y10 output, which is incorrect, should be y13.
Also, there seems to be no logical output for gear 5, check the datasheet, there is no output for those inputs.
Without that gear 5 being resolved, this wont work?? Any ideas?
One more thing:
I disconnected the HEx inverter to test some things:
it seems that, if I ground the circuit to the 0v GND of the USB joystick input (the one that yields 5+ through the red wire)
then each gear when selected, selects a combination of either 5 or 6 buttons simultaneously,
...12345678 <--- joystick buttons on test program on pc. (little red lights show on the program when a button is activated)
1|11011010
2|11110110
3|havent rewired this one correctly yet
4|11101110
5|this one has no output as previously discussed
6|11011010
In a way it kind of works, because each gear represents a comination of many outputs.
If I ground to the common y1-y6 track though, they are all on all the time.
Right now, logically, I am stumped. Theoretically, the circuit should work, I understand completely the HIGH and LOW concept, and througoughly tested the circuit input by input/ output by output, and the cicuit works (except for those two gears, but that cant possibly throw the whole thing off). I think that I am interfacing into the joystick board incorrectly.