The waveboard may need a jump start by giving the wheel attached to the motor a spin. This should start the string oscillating. The wavelength can be adjusted by string tension. Turn on the stroboscope with the forward knob or power button. Adjust the frequency of the strobe with the dial on the back.
Adjustment permits one to find the string frequency.
Turn off the classroom lights for the full effect. Tuning Forks - One is a fixed pitch fork, and the other is adjustable. They work well in conjunction with the oscilloscope to demonstrate waveform and pure tone. The students swinging the Doppler tubes need ample space. Make sure the students don't move around while the lights are off to minimize the possibility of injury.