I've been stuck finding a solution that doesn't require 64 more parts!

How would others rate the chance of the problem being cross talk from the output ("strobed") lines?

I'm thinking the simplest might be to run a twisted pair of a cat5 for each conductor that the op has now.
One of which (from each pair) would be unused and tied to common.

It would only double the lead count.
Only slightly more complex wiring progect.

But would it help?

Any other fix might involve 64 switching devices. Even in a chip the pin count is huge.

 

one important problem i can see is the possibility of switch bounce causing counting problems........you may need to add a little bit more electronics to cure it...not a difficult job to do

True, but multiplied by 64, right.

 

yes as you use individual switches to trigger the main unit....it may be worth trying it just for one input to see if it works-but the problem may be the amount of cable you have and /or noise pickup because of insufficient screening.

 

One possible solution that won't require starting over.

The strobe lines, either rows or column, are outputs and should not be subject to noise.

The other 8 leads may be high enough impedance to trigger with noise from switches.

If we can determine if these lines pull low or pull high, then a pull up/down resistor on each, of about 10-100k, may lower the impedance enough to make them immune to cross talk.

That seems to be easiest to implement, if anyone else thought it was worth a shot.

 

yes that could work,a transistor buffer stage for each ip may help also -design of which depends on how the input is looking for its trigger signal-hi going or lo going on trigger-just to give each input a better chance of switching with the long cable lengths /type of cable used

 

yes that could work,a transistor buffer stage for each ip may help also -design of which depends on how the input is looking for its trigger signal-hi going or lo going on trigger-just to give each input a better chance of switching with the long cable lengths /type of cable used

Hope op comes back. This project is kind of stuck in my head.

With 64 switches, even the transistor or ic buffer solution may push it into the don't bother category.

 

but if using discretes with careful layout the electronics can be built quite small