Dcmotor control using sonar to determine the speed

please help, im doing an interactive artwork where i need to be able to vary the speed of a DC motor using an arduino, i want to be able to use a sonar to determine the speed, is this possible?? i have all the components listed in the playground/main/DCmotorcontrol but the schematic is wrong are there any other visual references i can use? please help ASAP. thanks
Andrew

You may want to spend a bit of time with Google. I searched for "tip120 motor" and the first four hits looked rather helpful.

there any other visual references i can use?

It doesn’t give you the silly physical layout diagrams but motor control is so simple.

http://www.thebox.myzen.co.uk/Workshop/Motors_1.html
and
http://www.thebox.myzen.co.uk/Workshop/Motors_2.html