Digital signal

Hey everybody, i have a problem. I am trying to transfer digital signal over air. I am using IR LED and RECEIVER LED. I managed to control motor using PWM to blink IR LED. But in this way i only can control one thing. Now i want to control motor speed and led. What i need to do? How to make digital signal in binary? Please help me!!!

A digital signal is pretty much by definition in binary

Yeah, but how to do this, for example, how to transfer word: ''Hello!" over IR LED?

Try Googling "IRDA"

Thanks! I will check!