I need to make a prototype that will indicate, through both leds and audio tones, whether a person within its target area of 10 ft is walking or running. Unit will transmit a ultrasonic wave into the target area and will detect the Doppler shift of the reflected waves to determine the velocity of the person. A walking person is less then 5 ft per second. can have a power supply of 120 volts and 60 hz. and less then 15 watts of power consumption. Does anyone know were i can find a re fence to use in order to make something like this and were would be the best place to buy the parts. I know i have to use a transducer in order to make it work and the Doppler effect. But any tips or a way to find a re fence model or design that has all ready been done so i can follow it thanks please help. This is for a school project.