how to replace a Timer with a Matlab function

Hi everybody. This is the idea that I would like to develop: now I have set a Timer where a step controls a switch, sending 1 or 0 according to signal settings.

What I would like to do is to replace the timer with a function which could allow to control by keyboard, so that I press 1 or 0 to control the switch. ( I had also thought to use Space to switch from 1 to 0 and viceversa, but I have some doubts about space character to use in strcmp function)

The thing is that the possibility to control the switch by keyboard should keep existing for all the simulation duration, in order to see how the system reacts while I press 1 or 0 key, which would be the switch input g.

Thank you