Posted by StephenH on 8, 2001 at 9:26 PM:
In Reply to: Pole Position Shifter Problem or Keyboard Hack Problem posted by Rob on 7, 2001 at 1:01 AM:
Given the results, I suspect the wiring digram is this:
1) Common
2) High Gear
3) Low Gear
If this is correct, I would wire the common wire to the common line on the encoder, and the high and low to a key (for a two key setup).
For a one key setup: you need a bit of logic. Find out the voltage the encoder sends to the keys. Then, create an R-S flip-flop using two NAND gates. To create an R-S Flip-flop connect one input of each NAND gate to the OUTPUT of the other. These are considered Q and _Q (Not Q). The other NAND inputs (not connected to anything) are R and S. Power the NAND chip +5 and Ground (unless your encoder uses a different voltage.
R Input - Pin 3
S Input - Pin 2
Power or Ground* - Pin 1.
This should allow a key input set from the shifter as High (key pressed) and Low (key NOT pressed).
TTL chips need ground for a low input (read non-connected as high), and CMOS is the opposite (If I remember correctly.
: I am attempting to connect a Pole Position Control Panel to a Hacked keyboard. The problem I have with the shifter is this. There are three connectors on the control. I will label them 1,2, & 3. When 1 & 2 are connected the the keyboard and the shifter is in high gear I get a constant stream from the space key. While the control is in low gear I get nothing in this configuration. When 1 & 3 are connected I get the constant stream in low gear and not high. As I would expect 2 & 3 do nothing.
: Ok Here is my question. Is there a way to modify this so only first keypress is registered and all others are ignored. I thought about disabling this in bios, but I need the capability for the gas pedal.
: Thanks