Fig. 1: Low-cost smartphone-based tympanometer.
a All components of the hand-held tympanometer fit into a portable 3D printed enclosure that attaches to the back of a smartphone. b A desktop version of our tympanometer. c Close-up of PCB containing the key acoustic and pressure sensing elements of the tympanometer. The PCB includes a microcontroller, Bluetooth antenna and micro-USB port for computing, communication, and power respectively. d Through precise movements of a plunger and syringe, the stepper motor introduces positive and negative pressure into the ear canal. The green line is a reference marker for the plunger location at the beginning of the measurement. The plunger moves 5.3 mm to perform the pressure sweep from 200 to −400 daPa.
