the order in which some switches are turned on

Hi all,

I have an array of N switches . Initially all are OFF.

Somebody turns them ON in some order. It is possible that more
switches are turned ON in the same moment.

I need a device which shows me the order in which the switches were
turned ON. For instance the device should give me: 4,3,1,5,2 (this is
the order in which the switches were turned ON).

The way in which the output is shown in not im****tant. It must be
simple to read (by a human, computer, etc).

It is im****tant that the device is able to handle the turned ON (in
the same moment) of the multiple switches.

thanks,
Laura