I am building a software/Hardware MIDI controller. The hardware is about using the PC Joystick port to read potentiometers and buttons. I read that the joystick port used a timer (555) and a RC combination to calculate the potentiometer resistance values based on how much time it takes for the capacitor to charge. Good so far. The point is that when I try 10K pots to build a music keyboard , the readings of the 10K pot (or 1k pots) are of 2 values (example 1279 or 1356 ) they are ALWAYS this 2 values. I can manage this behaviour in the sofware, but can you tell me why it reads 2 values for every 10k resistor (the values are in pairs but always the same pair values)?
Example: (these are not the actual values, but just the concept of what the reading are generated). I though that I will get only one value for each resistance.
10K -> 1279 or 1356
20k -> 1450 or 1546
30k -> 1600 or 1680
etc,
Again, don't try to make any calculation with this values. There are not the actual readings.
Thanks