On Fri, Oct 31, 2003 at 09:25:34PM +0800, Chris McCormick wrote:
An idea I had recently (though I'm sure it's not original) is to hook up 8 555-timer circuits with variable resistors to the parallel port and poll it periodically to figure out the frequency of the 8 squarewaves on individual parallel port pins. These frequencies could be used as control values in a Pd patch. The advantages are that 555 timer circuits with a variable resistor are very cheap, and simple. Your range would be from where frequency updates are too far between (let's say 100Hz) to the upper-range of the parallel port polling frequency. So if you can poll it at 8000Hz you would probably want to stop at nyquist to get meaningful updates let's say at 4000Hz (not quite certain that nyquist is relevant here though).
Interesting, but I'm not sure it's possible to poll the parallel port as fast. With my parapin object, I use 1Khz by default, which correspond to the maximum resolution of timers in PD (but I might be wrong). http://www.pure-data.org/Members/odradek/parapin -- Marc