The Dink Network

It sounds like the button brain would be ideal for this. (Otherwise you need to set touch damage to 0 when Dink steps on the pad or void touch will repeat over and over again, and again to -1 when Dink gets off)

//add in void main
sp_brain(&current_sprite,14);

//replace void touch with
void buttonon()
{
sp_seq(&current_sprite, 100);
sp_frame(&current_sprite, 1);
sp_brain(&current_sprite, 6);
if (&current_sprite == &light1)
{
say_stop("Hello!", 1);
}
}

You were also missing one = in the if-check.