Serial Monitor "button" implementation
A simple approach would be to use bit 0 of serial data to control "button 1", and bit 1 of serial data to control "button 2".  As follows:

char sd = Serial.read();
byte button1 = sd &amp; 1;
byte button2 = sd &amp; 2; // Or (sd &amp; 2)&gt;&gt;1 if you prefer


With the above code, button 1 is true for odd-digit inputs, and button 2 is true when (sd &amp; 2)&gt;&gt;1 is odd.  For example, input 0 to turn off both buttons, 1 to turn on only button 1, 2 for only button 2, and 3 to turn on both.  

You might also wish to button1 or button2 only when the input character represents a digit.  For this, you can say:

char sd = Serial.read();
byte button1, button2;
... ;
if ('0' &lt;= sd &amp;&amp; sd &lt;= '9') {
    button1 = sd &amp; 1;
    button2 = (sd &amp; 2)&gt;&gt;1;
}