My millis() code doesn't work
I don't think anything in your code is going to work.
First,
 you are asking the serial.Read to return an integer if it is working.  You might want to change that to a Boolean.

Second,
You are asking for a 1 and only a 1 to make your next if statement true.  If the serial.Read is working the chance it will only return a one, I think is very low

Third,
On the IF statement for setting timerReady. You will set that at a new number each time the program runs through, with the 90ms delay in the last IF statement, it looks like your timer will reset at about every 95-100ms

Fourth,
I think your last 2 IF statements are wrong, I think you want 

if(timerReady==true) {
    if((currentMillis - lastreceivedtime) &gt;= timebetween){
      digitalWrite(11, HIGH);
      delay(90);


If you do get this working you might need to set the Boolean back to false and move pin 11 to low at some point.