Ronald Leenes wrote:

Hi,

for a project we have a very large key-matrix (32x24). We have a problem
with phantom keys (when three keys in a rectangle are pressed, also the
fourth corner is seen as pressed).
How do we solve this problem? I know something can be done with diodes,
but we can't get it to work. Can somebody give some hints.

An additional problem is that the 'keyboard' consists of panels that can
only be opened with great difficulty.

What is the most clever way to interface say 500 switches to a computer
(serial or usb)?

Best regards,

Ronald

If you add a diode in series with each contact point (either in series
with each row trace and the contact point, or in series with each
column trace and the contact point) you eliminate the phantom keys.
This makes the flexible circuits lumpy, though.

--
John Popelish