Wrist-mounted Ultrasonic Device

This project shows an ultrasonic device can be made small enough to be worn on the wrist and therefore added as a function for a running watch. An existing ultrasonic device was modified by stripping the circuit board to necessary components, replacing the 9V battery with a smaller alternative, and fitting it to a wrist mounted case. The wrist-mounted device shows a 68{\%} mass reduction and 84{\%} volume reduction and emits an ultrasonic frequency of 21-22kHz.